From a422d2aba5661d9f9ca54db8a1e7b11692d4cde4 Mon Sep 17 00:00:00 2001
From: Tan Li Hau <tanhauhau@users.noreply.github.com>
Date: Sat, 11 Jan 2020 22:01:40 +0800
Subject: [PATCH 01/82] fix actions having no access to parent nodes (#4252)

---
 CHANGELOG.md                                  |  1 +
 src/compiler/compile/render_dom/Block.ts      |  4 ++--
 .../action-custom-event-handler/expected.js   |  4 ++--
 test/js/samples/action/expected.js            |  2 +-
 test/js/samples/bind-online/expected.js       |  4 ++--
 test/js/samples/bind-open/expected.js         |  3 +--
 .../bindings-readonly-order/expected.js       | 10 ++++-----
 .../capture-inject-dev-only/expected.js       |  2 +-
 .../samples/component-static-var/expected.js  |  2 +-
 .../expected.js                               |  2 +-
 .../samples/dont-invalidate-this/expected.js  |  2 +-
 .../samples/event-handler-dynamic/expected.js | 16 +++++++-------
 .../event-handler-no-passive/expected.js      |  2 +-
 test/js/samples/event-modifiers/expected.js   | 14 ++++++------
 test/js/samples/input-files/expected.js       |  2 +-
 .../input-no-initial-value/expected.js        | 10 ++++-----
 test/js/samples/input-range/expected.js       |  8 +++----
 test/js/samples/input-value/expected.js       |  2 +-
 .../input-without-blowback-guard/expected.js  |  2 +-
 .../expected.js                               |  2 +-
 .../expected.js                               |  2 +-
 .../expected.js                               |  2 +-
 .../expected.js                               |  2 +-
 test/js/samples/media-bindings/expected.js    | 22 +++++++++----------
 test/js/samples/video-bindings/expected.js    |  8 +++----
 .../samples/window-binding-online/expected.js |  4 ++--
 .../samples/window-binding-scroll/expected.js | 10 ++++-----
 .../_config.js                                |  8 +++++++
 .../main.svelte                               |  8 +++++++
 29 files changed, 88 insertions(+), 72 deletions(-)
 create mode 100644 test/runtime/samples/action-receives-element-mounted/_config.js
 create mode 100644 test/runtime/samples/action-receives-element-mounted/main.svelte

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5e5d5df95f..f6af419913 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@
 
 * Prevent text input cursor jumping in Safari with one-way binding ([#3449](https://github.com/sveltejs/svelte/issues/3449))
 * Expose compiler version in dev events ([#4047](https://github.com/sveltejs/svelte/issues/4047))
+* Don't run actions before their element is in the document ([#4166](https://github.com/sveltejs/svelte/issues/4166))
 * Fix reactive assignments with destructuring and stores where the destructured value should be undefined ([#4170](https://github.com/sveltejs/svelte/issues/4170))
 * Do not automatically declare variables in reactive declarations when assigning to a member expression ([#4212](https://github.com/sveltejs/svelte/issues/4212))
 
diff --git a/src/compiler/compile/render_dom/Block.ts b/src/compiler/compile/render_dom/Block.ts
index c8fa884721..68d28024fe 100644
--- a/src/compiler/compile/render_dom/Block.ts
+++ b/src/compiler/compile/render_dom/Block.ts
@@ -450,7 +450,7 @@ export default class Block {
 			this.add_variable(dispose);
 
 			if (this.event_listeners.length === 1) {
-				this.chunks.hydrate.push(
+				this.chunks.mount.push(
 					b`${dispose} = ${this.event_listeners[0]};`
 				);
 
@@ -458,7 +458,7 @@ export default class Block {
 					b`${dispose}();`
 				);
 			} else {
-				this.chunks.hydrate.push(b`
+				this.chunks.mount.push(b`
 					${dispose} = [
 						${this.event_listeners}
 					];
diff --git a/test/js/samples/action-custom-event-handler/expected.js b/test/js/samples/action-custom-event-handler/expected.js
index da42603895..968b5965d5 100644
--- a/test/js/samples/action-custom-event-handler/expected.js
+++ b/test/js/samples/action-custom-event-handler/expected.js
@@ -20,10 +20,10 @@ function create_fragment(ctx) {
 		c() {
 			button = element("button");
 			button.textContent = "foo";
-			dispose = action_destroyer(foo_action = foo.call(null, button, /*foo_function*/ ctx[1]));
 		},
 		m(target, anchor) {
 			insert(target, button, anchor);
+			dispose = action_destroyer(foo_action = foo.call(null, button, /*foo_function*/ ctx[1]));
 		},
 		p(ctx, [dirty]) {
 			if (foo_action && is_function(foo_action.update) && dirty & /*bar*/ 1) foo_action.update.call(null, /*foo_function*/ ctx[1]);
@@ -42,7 +42,7 @@ function handleFoo(bar) {
 }
 
 function foo(node, callback) {
-
+	
 }
 
 function instance($$self, $$props, $$invalidate) {
diff --git a/test/js/samples/action/expected.js b/test/js/samples/action/expected.js
index dc3ebb5cf8..22d9cd939c 100644
--- a/test/js/samples/action/expected.js
+++ b/test/js/samples/action/expected.js
@@ -21,10 +21,10 @@ function create_fragment(ctx) {
 			a = element("a");
 			a.textContent = "Test";
 			attr(a, "href", "#");
-			dispose = action_destroyer(link_action = link.call(null, a));
 		},
 		m(target, anchor) {
 			insert(target, a, anchor);
+			dispose = action_destroyer(link_action = link.call(null, a));
 		},
 		p: noop,
 		i: noop,
diff --git a/test/js/samples/bind-online/expected.js b/test/js/samples/bind-online/expected.js
index 8285646481..e129e66d71 100644
--- a/test/js/samples/bind-online/expected.js
+++ b/test/js/samples/bind-online/expected.js
@@ -14,13 +14,13 @@ function create_fragment(ctx) {
 	add_render_callback(/*onlinestatuschanged*/ ctx[1]);
 
 	return {
-		c() {
+		c: noop,
+		m(target, anchor) {
 			dispose = [
 				listen(window, "online", /*onlinestatuschanged*/ ctx[1]),
 				listen(window, "offline", /*onlinestatuschanged*/ ctx[1])
 			];
 		},
-		m: noop,
 		p: noop,
 		i: noop,
 		o: noop,
diff --git a/test/js/samples/bind-open/expected.js b/test/js/samples/bind-open/expected.js
index d4f148cac9..7d66145f0a 100644
--- a/test/js/samples/bind-open/expected.js
+++ b/test/js/samples/bind-open/expected.js
@@ -20,12 +20,11 @@ function create_fragment(ctx) {
 
 			details.innerHTML = `<summary>summary</summary>content
 `;
-
-			dispose = listen(details, "toggle", /*details_toggle_handler*/ ctx[1]);
 		},
 		m(target, anchor) {
 			insert(target, details, anchor);
 			details.open = /*open*/ ctx[0];
+			dispose = listen(details, "toggle", /*details_toggle_handler*/ ctx[1]);
 		},
 		p(ctx, [dirty]) {
 			if (dirty & /*open*/ 1) {
diff --git a/test/js/samples/bindings-readonly-order/expected.js b/test/js/samples/bindings-readonly-order/expected.js
index cf30686662..db0e7cb007 100644
--- a/test/js/samples/bindings-readonly-order/expected.js
+++ b/test/js/samples/bindings-readonly-order/expected.js
@@ -26,16 +26,16 @@ function create_fragment(ctx) {
 			input1 = element("input");
 			attr(input0, "type", "file");
 			attr(input1, "type", "file");
-
-			dispose = [
-				listen(input0, "change", /*input0_change_handler*/ ctx[1]),
-				listen(input1, "change", /*input1_change_handler*/ ctx[2])
-			];
 		},
 		m(target, anchor) {
 			insert(target, input0, anchor);
 			insert(target, t, anchor);
 			insert(target, input1, anchor);
+
+			dispose = [
+				listen(input0, "change", /*input0_change_handler*/ ctx[1]),
+				listen(input1, "change", /*input1_change_handler*/ ctx[2])
+			];
 		},
 		p: noop,
 		i: noop,
diff --git a/test/js/samples/capture-inject-dev-only/expected.js b/test/js/samples/capture-inject-dev-only/expected.js
index 6c639d9207..a314b0cff3 100644
--- a/test/js/samples/capture-inject-dev-only/expected.js
+++ b/test/js/samples/capture-inject-dev-only/expected.js
@@ -28,7 +28,6 @@ function create_fragment(ctx) {
 			t0 = text(/*foo*/ ctx[0]);
 			t1 = space();
 			input = element("input");
-			dispose = listen(input, "input", /*input_input_handler*/ ctx[1]);
 		},
 		m(target, anchor) {
 			insert(target, p, anchor);
@@ -36,6 +35,7 @@ function create_fragment(ctx) {
 			insert(target, t1, anchor);
 			insert(target, input, anchor);
 			set_input_value(input, /*foo*/ ctx[0]);
+			dispose = listen(input, "input", /*input_input_handler*/ ctx[1]);
 		},
 		p(ctx, [dirty]) {
 			if (dirty & /*foo*/ 1) set_data(t0, /*foo*/ ctx[0]);
diff --git a/test/js/samples/component-static-var/expected.js b/test/js/samples/component-static-var/expected.js
index e01402b6d4..a65d9186a7 100644
--- a/test/js/samples/component-static-var/expected.js
+++ b/test/js/samples/component-static-var/expected.js
@@ -35,7 +35,6 @@ function create_fragment(ctx) {
 			create_component(bar.$$.fragment);
 			t1 = space();
 			input = element("input");
-			dispose = listen(input, "input", /*input_input_handler*/ ctx[1]);
 		},
 		m(target, anchor) {
 			mount_component(foo, target, anchor);
@@ -45,6 +44,7 @@ function create_fragment(ctx) {
 			insert(target, input, anchor);
 			set_input_value(input, /*z*/ ctx[0]);
 			current = true;
+			dispose = listen(input, "input", /*input_input_handler*/ ctx[1]);
 		},
 		p(ctx, [dirty]) {
 			const bar_changes = {};
diff --git a/test/js/samples/component-store-reassign-invalidate/expected.js b/test/js/samples/component-store-reassign-invalidate/expected.js
index 02a74cf22e..771b20dec4 100644
--- a/test/js/samples/component-store-reassign-invalidate/expected.js
+++ b/test/js/samples/component-store-reassign-invalidate/expected.js
@@ -31,13 +31,13 @@ function create_fragment(ctx) {
 			t1 = space();
 			button = element("button");
 			button.textContent = "reset";
-			dispose = listen(button, "click", /*click_handler*/ ctx[2]);
 		},
 		m(target, anchor) {
 			insert(target, h1, anchor);
 			append(h1, t0);
 			insert(target, t1, anchor);
 			insert(target, button, anchor);
+			dispose = listen(button, "click", /*click_handler*/ ctx[2]);
 		},
 		p(ctx, [dirty]) {
 			if (dirty & /*$foo*/ 2) set_data(t0, /*$foo*/ ctx[1]);
diff --git a/test/js/samples/dont-invalidate-this/expected.js b/test/js/samples/dont-invalidate-this/expected.js
index 98f638dfcf..f5f6d07812 100644
--- a/test/js/samples/dont-invalidate-this/expected.js
+++ b/test/js/samples/dont-invalidate-this/expected.js
@@ -17,10 +17,10 @@ function create_fragment(ctx) {
 	return {
 		c() {
 			input = element("input");
-			dispose = listen(input, "input", make_uppercase);
 		},
 		m(target, anchor) {
 			insert(target, input, anchor);
+			dispose = listen(input, "input", make_uppercase);
 		},
 		p: noop,
 		i: noop,
diff --git a/test/js/samples/event-handler-dynamic/expected.js b/test/js/samples/event-handler-dynamic/expected.js
index 42c6b2951a..16b4a3f626 100644
--- a/test/js/samples/event-handler-dynamic/expected.js
+++ b/test/js/samples/event-handler-dynamic/expected.js
@@ -42,14 +42,6 @@ function create_fragment(ctx) {
 			t5 = space();
 			button2 = element("button");
 			button2.textContent = "click";
-
-			dispose = [
-				listen(button0, "click", /*updateHandler1*/ ctx[2]),
-				listen(button1, "click", /*updateHandler2*/ ctx[3]),
-				listen(button2, "click", function () {
-					if (is_function(/*clickHandler*/ ctx[0])) /*clickHandler*/ ctx[0].apply(this, arguments);
-				})
-			];
 		},
 		m(target, anchor) {
 			insert(target, p0, anchor);
@@ -61,6 +53,14 @@ function create_fragment(ctx) {
 			append(p1, t4);
 			insert(target, t5, anchor);
 			insert(target, button2, anchor);
+
+			dispose = [
+				listen(button0, "click", /*updateHandler1*/ ctx[2]),
+				listen(button1, "click", /*updateHandler2*/ ctx[3]),
+				listen(button2, "click", function () {
+					if (is_function(/*clickHandler*/ ctx[0])) /*clickHandler*/ ctx[0].apply(this, arguments);
+				})
+			];
 		},
 		p(new_ctx, [dirty]) {
 			ctx = new_ctx;
diff --git a/test/js/samples/event-handler-no-passive/expected.js b/test/js/samples/event-handler-no-passive/expected.js
index 6f04e67808..c519fac668 100644
--- a/test/js/samples/event-handler-no-passive/expected.js
+++ b/test/js/samples/event-handler-no-passive/expected.js
@@ -20,10 +20,10 @@ function create_fragment(ctx) {
 			a = element("a");
 			a.textContent = "this should not navigate to example.com";
 			attr(a, "href", "https://example.com");
-			dispose = listen(a, "touchstart", touchstart_handler);
 		},
 		m(target, anchor) {
 			insert(target, a, anchor);
+			dispose = listen(a, "touchstart", touchstart_handler);
 		},
 		p: noop,
 		i: noop,
diff --git a/test/js/samples/event-modifiers/expected.js b/test/js/samples/event-modifiers/expected.js
index 3f324bb76d..252034a431 100644
--- a/test/js/samples/event-modifiers/expected.js
+++ b/test/js/samples/event-modifiers/expected.js
@@ -35,13 +35,6 @@ function create_fragment(ctx) {
 			t3 = space();
 			button2 = element("button");
 			button2.textContent = "or me!";
-
-			dispose = [
-				listen(button0, "click", stop_propagation(prevent_default(handleClick))),
-				listen(button1, "click", handleClick, { once: true, capture: true }),
-				listen(button2, "click", handleClick, true),
-				listen(div, "touchstart", handleTouchstart, { passive: true })
-			];
 		},
 		m(target, anchor) {
 			insert(target, div, anchor);
@@ -50,6 +43,13 @@ function create_fragment(ctx) {
 			append(div, button1);
 			append(div, t3);
 			append(div, button2);
+
+			dispose = [
+				listen(button0, "click", stop_propagation(prevent_default(handleClick))),
+				listen(button1, "click", handleClick, { once: true, capture: true }),
+				listen(button2, "click", handleClick, true),
+				listen(div, "touchstart", handleTouchstart, { passive: true })
+			];
 		},
 		p: noop,
 		i: noop,
diff --git a/test/js/samples/input-files/expected.js b/test/js/samples/input-files/expected.js
index c3e46f0c79..2a2254fbd7 100644
--- a/test/js/samples/input-files/expected.js
+++ b/test/js/samples/input-files/expected.js
@@ -20,10 +20,10 @@ function create_fragment(ctx) {
 			input = element("input");
 			attr(input, "type", "file");
 			input.multiple = true;
-			dispose = listen(input, "change", /*input_change_handler*/ ctx[1]);
 		},
 		m(target, anchor) {
 			insert(target, input, anchor);
+			dispose = listen(input, "change", /*input_change_handler*/ ctx[1]);
 		},
 		p: noop,
 		i: noop,
diff --git a/test/js/samples/input-no-initial-value/expected.js b/test/js/samples/input-no-initial-value/expected.js
index 8ff2b2798b..d588f0bf73 100644
--- a/test/js/samples/input-no-initial-value/expected.js
+++ b/test/js/samples/input-no-initial-value/expected.js
@@ -31,11 +31,6 @@ function create_fragment(ctx) {
 			button.textContent = "Store";
 			attr(input, "type", "text");
 			input.required = true;
-
-			dispose = [
-				listen(input, "input", /*input_input_handler*/ ctx[2]),
-				listen(form, "submit", /*handleSubmit*/ ctx[1])
-			];
 		},
 		m(target, anchor) {
 			insert(target, form, anchor);
@@ -43,6 +38,11 @@ function create_fragment(ctx) {
 			set_input_value(input, /*test*/ ctx[0]);
 			append(form, t0);
 			append(form, button);
+
+			dispose = [
+				listen(input, "input", /*input_input_handler*/ ctx[2]),
+				listen(form, "submit", /*handleSubmit*/ ctx[1])
+			];
 		},
 		p(ctx, [dirty]) {
 			if (dirty & /*test*/ 1 && input.value !== /*test*/ ctx[0]) {
diff --git a/test/js/samples/input-range/expected.js b/test/js/samples/input-range/expected.js
index 5a074d9754..12dfd3e90e 100644
--- a/test/js/samples/input-range/expected.js
+++ b/test/js/samples/input-range/expected.js
@@ -22,16 +22,16 @@ function create_fragment(ctx) {
 		c() {
 			input = element("input");
 			attr(input, "type", "range");
+		},
+		m(target, anchor) {
+			insert(target, input, anchor);
+			set_input_value(input, /*value*/ ctx[0]);
 
 			dispose = [
 				listen(input, "change", /*input_change_input_handler*/ ctx[1]),
 				listen(input, "input", /*input_change_input_handler*/ ctx[1])
 			];
 		},
-		m(target, anchor) {
-			insert(target, input, anchor);
-			set_input_value(input, /*value*/ ctx[0]);
-		},
 		p(ctx, [dirty]) {
 			if (dirty & /*value*/ 1) {
 				set_input_value(input, /*value*/ ctx[0]);
diff --git a/test/js/samples/input-value/expected.js b/test/js/samples/input-value/expected.js
index 81753441e4..21c7bfc83b 100644
--- a/test/js/samples/input-value/expected.js
+++ b/test/js/samples/input-value/expected.js
@@ -30,7 +30,6 @@ function create_fragment(ctx) {
 			t1 = text(/*name*/ ctx[0]);
 			t2 = text("!");
 			input.value = /*name*/ ctx[0];
-			dispose = listen(input, "input", /*onInput*/ ctx[1]);
 		},
 		m(target, anchor) {
 			insert(target, input, anchor);
@@ -38,6 +37,7 @@ function create_fragment(ctx) {
 			insert(target, h1, anchor);
 			append(h1, t1);
 			append(h1, t2);
+			dispose = listen(input, "input", /*onInput*/ ctx[1]);
 		},
 		p(ctx, [dirty]) {
 			if (dirty & /*name*/ 1 && input.value !== /*name*/ ctx[0]) {
diff --git a/test/js/samples/input-without-blowback-guard/expected.js b/test/js/samples/input-without-blowback-guard/expected.js
index 344976ade6..fefe867e14 100644
--- a/test/js/samples/input-without-blowback-guard/expected.js
+++ b/test/js/samples/input-without-blowback-guard/expected.js
@@ -19,11 +19,11 @@ function create_fragment(ctx) {
 		c() {
 			input = element("input");
 			attr(input, "type", "checkbox");
-			dispose = listen(input, "change", /*input_change_handler*/ ctx[1]);
 		},
 		m(target, anchor) {
 			insert(target, input, anchor);
 			input.checked = /*foo*/ ctx[0];
+			dispose = listen(input, "change", /*input_change_handler*/ ctx[1]);
 		},
 		p(ctx, [dirty]) {
 			if (dirty & /*foo*/ 1) {
diff --git a/test/js/samples/instrumentation-script-if-no-block/expected.js b/test/js/samples/instrumentation-script-if-no-block/expected.js
index 4127a6d7d6..7634481a2d 100644
--- a/test/js/samples/instrumentation-script-if-no-block/expected.js
+++ b/test/js/samples/instrumentation-script-if-no-block/expected.js
@@ -30,7 +30,6 @@ function create_fragment(ctx) {
 			p = element("p");
 			t2 = text("x: ");
 			t3 = text(/*x*/ ctx[0]);
-			dispose = listen(button, "click", /*foo*/ ctx[1]);
 		},
 		m(target, anchor) {
 			insert(target, button, anchor);
@@ -38,6 +37,7 @@ function create_fragment(ctx) {
 			insert(target, p, anchor);
 			append(p, t2);
 			append(p, t3);
+			dispose = listen(button, "click", /*foo*/ ctx[1]);
 		},
 		p(ctx, [dirty]) {
 			if (dirty & /*x*/ 1) set_data(t3, /*x*/ ctx[0]);
diff --git a/test/js/samples/instrumentation-script-x-equals-x/expected.js b/test/js/samples/instrumentation-script-x-equals-x/expected.js
index 0d4493baf3..c154608cd5 100644
--- a/test/js/samples/instrumentation-script-x-equals-x/expected.js
+++ b/test/js/samples/instrumentation-script-x-equals-x/expected.js
@@ -31,7 +31,6 @@ function create_fragment(ctx) {
 			p = element("p");
 			t2 = text("number of things: ");
 			t3 = text(t3_value);
-			dispose = listen(button, "click", /*foo*/ ctx[1]);
 		},
 		m(target, anchor) {
 			insert(target, button, anchor);
@@ -39,6 +38,7 @@ function create_fragment(ctx) {
 			insert(target, p, anchor);
 			append(p, t2);
 			append(p, t3);
+			dispose = listen(button, "click", /*foo*/ ctx[1]);
 		},
 		p(ctx, [dirty]) {
 			if (dirty & /*things*/ 1 && t3_value !== (t3_value = /*things*/ ctx[0].length + "")) set_data(t3, t3_value);
diff --git a/test/js/samples/instrumentation-template-if-no-block/expected.js b/test/js/samples/instrumentation-template-if-no-block/expected.js
index 0bd627eb87..77780baa99 100644
--- a/test/js/samples/instrumentation-template-if-no-block/expected.js
+++ b/test/js/samples/instrumentation-template-if-no-block/expected.js
@@ -30,7 +30,6 @@ function create_fragment(ctx) {
 			p = element("p");
 			t2 = text("x: ");
 			t3 = text(/*x*/ ctx[0]);
-			dispose = listen(button, "click", /*click_handler*/ ctx[1]);
 		},
 		m(target, anchor) {
 			insert(target, button, anchor);
@@ -38,6 +37,7 @@ function create_fragment(ctx) {
 			insert(target, p, anchor);
 			append(p, t2);
 			append(p, t3);
+			dispose = listen(button, "click", /*click_handler*/ ctx[1]);
 		},
 		p(ctx, [dirty]) {
 			if (dirty & /*x*/ 1) set_data(t3, /*x*/ ctx[0]);
diff --git a/test/js/samples/instrumentation-template-x-equals-x/expected.js b/test/js/samples/instrumentation-template-x-equals-x/expected.js
index e049a6d39b..4fe45616c7 100644
--- a/test/js/samples/instrumentation-template-x-equals-x/expected.js
+++ b/test/js/samples/instrumentation-template-x-equals-x/expected.js
@@ -31,7 +31,6 @@ function create_fragment(ctx) {
 			p = element("p");
 			t2 = text("number of things: ");
 			t3 = text(t3_value);
-			dispose = listen(button, "click", /*click_handler*/ ctx[1]);
 		},
 		m(target, anchor) {
 			insert(target, button, anchor);
@@ -39,6 +38,7 @@ function create_fragment(ctx) {
 			insert(target, p, anchor);
 			append(p, t2);
 			append(p, t3);
+			dispose = listen(button, "click", /*click_handler*/ ctx[1]);
 		},
 		p(ctx, [dirty]) {
 			if (dirty & /*things*/ 1 && t3_value !== (t3_value = /*things*/ ctx[0].length + "")) set_data(t3, t3_value);
diff --git a/test/js/samples/media-bindings/expected.js b/test/js/samples/media-bindings/expected.js
index b5548a3efe..52fef36792 100644
--- a/test/js/samples/media-bindings/expected.js
+++ b/test/js/samples/media-bindings/expected.js
@@ -41,6 +41,17 @@ function create_fragment(ctx) {
 			if (/*duration*/ ctx[4] === void 0) add_render_callback(() => /*audio_durationchange_handler*/ ctx[13].call(audio));
 			if (/*seeking*/ ctx[8] === void 0) add_render_callback(() => /*audio_seeking_seeked_handler*/ ctx[17].call(audio));
 			if (/*ended*/ ctx[9] === void 0) add_render_callback(() => /*audio_ended_handler*/ ctx[18].call(audio));
+		},
+		m(target, anchor) {
+			insert(target, audio, anchor);
+
+			if (!isNaN(/*volume*/ ctx[6])) {
+				audio.volume = /*volume*/ ctx[6];
+			}
+
+			if (!isNaN(/*playbackRate*/ ctx[7])) {
+				audio.playbackRate = /*playbackRate*/ ctx[7];
+			}
 
 			dispose = [
 				listen(audio, "progress", /*audio_progress_handler*/ ctx[10]),
@@ -56,17 +67,6 @@ function create_fragment(ctx) {
 				listen(audio, "ended", /*audio_ended_handler*/ ctx[18])
 			];
 		},
-		m(target, anchor) {
-			insert(target, audio, anchor);
-
-			if (!isNaN(/*volume*/ ctx[6])) {
-				audio.volume = /*volume*/ ctx[6];
-			}
-
-			if (!isNaN(/*playbackRate*/ ctx[7])) {
-				audio.playbackRate = /*playbackRate*/ ctx[7];
-			}
-		},
 		p(ctx, [dirty]) {
 			if (!audio_updating && dirty & /*currentTime*/ 8 && !isNaN(/*currentTime*/ ctx[3])) {
 				audio.currentTime = /*currentTime*/ ctx[3];
diff --git a/test/js/samples/video-bindings/expected.js b/test/js/samples/video-bindings/expected.js
index 5b734a70a6..c8cd1d84ce 100644
--- a/test/js/samples/video-bindings/expected.js
+++ b/test/js/samples/video-bindings/expected.js
@@ -37,16 +37,16 @@ function create_fragment(ctx) {
 			video = element("video");
 			if (/*videoHeight*/ ctx[1] === void 0 || /*videoWidth*/ ctx[2] === void 0) add_render_callback(() => /*video_resize_handler*/ ctx[5].call(video));
 			add_render_callback(() => /*video_elementresize_handler*/ ctx[6].call(video));
+		},
+		m(target, anchor) {
+			insert(target, video, anchor);
+			video_resize_listener = add_resize_listener(video, /*video_elementresize_handler*/ ctx[6].bind(video));
 
 			dispose = [
 				listen(video, "timeupdate", video_timeupdate_handler),
 				listen(video, "resize", /*video_resize_handler*/ ctx[5])
 			];
 		},
-		m(target, anchor) {
-			insert(target, video, anchor);
-			video_resize_listener = add_resize_listener(video, /*video_elementresize_handler*/ ctx[6].bind(video));
-		},
 		p(ctx, [dirty]) {
 			if (!video_updating && dirty & /*currentTime*/ 1 && !isNaN(/*currentTime*/ ctx[0])) {
 				video.currentTime = /*currentTime*/ ctx[0];
diff --git a/test/js/samples/window-binding-online/expected.js b/test/js/samples/window-binding-online/expected.js
index 8285646481..e129e66d71 100644
--- a/test/js/samples/window-binding-online/expected.js
+++ b/test/js/samples/window-binding-online/expected.js
@@ -14,13 +14,13 @@ function create_fragment(ctx) {
 	add_render_callback(/*onlinestatuschanged*/ ctx[1]);
 
 	return {
-		c() {
+		c: noop,
+		m(target, anchor) {
 			dispose = [
 				listen(window, "online", /*onlinestatuschanged*/ ctx[1]),
 				listen(window, "offline", /*onlinestatuschanged*/ ctx[1])
 			];
 		},
-		m: noop,
 		p: noop,
 		i: noop,
 		o: noop,
diff --git a/test/js/samples/window-binding-scroll/expected.js b/test/js/samples/window-binding-scroll/expected.js
index f79212e25e..70c39eedd2 100644
--- a/test/js/samples/window-binding-scroll/expected.js
+++ b/test/js/samples/window-binding-scroll/expected.js
@@ -33,6 +33,11 @@ function create_fragment(ctx) {
 			p = element("p");
 			t0 = text("scrolled to ");
 			t1 = text(/*y*/ ctx[0]);
+		},
+		m(target, anchor) {
+			insert(target, p, anchor);
+			append(p, t0);
+			append(p, t1);
 
 			dispose = listen(window, "scroll", () => {
 				scrolling = true;
@@ -41,11 +46,6 @@ function create_fragment(ctx) {
 				/*onwindowscroll*/ ctx[1]();
 			});
 		},
-		m(target, anchor) {
-			insert(target, p, anchor);
-			append(p, t0);
-			append(p, t1);
-		},
 		p(ctx, [dirty]) {
 			if (dirty & /*y*/ 1 && !scrolling) {
 				scrolling = true;
diff --git a/test/runtime/samples/action-receives-element-mounted/_config.js b/test/runtime/samples/action-receives-element-mounted/_config.js
new file mode 100644
index 0000000000..0806d0fa90
--- /dev/null
+++ b/test/runtime/samples/action-receives-element-mounted/_config.js
@@ -0,0 +1,8 @@
+const result = {};
+
+export default {
+	props: { result },
+	async test({ assert, component, target, window }) {
+		assert.notEqual(result.parentElement, null);
+	}
+};
diff --git a/test/runtime/samples/action-receives-element-mounted/main.svelte b/test/runtime/samples/action-receives-element-mounted/main.svelte
new file mode 100644
index 0000000000..a53ce81de0
--- /dev/null
+++ b/test/runtime/samples/action-receives-element-mounted/main.svelte
@@ -0,0 +1,8 @@
+<script>
+	export let result;
+	function onMountAction(node) {
+		result.parentElement = node.parentElement;
+	}
+</script>
+
+<h1 use:onMountAction>Hello!</h1>
\ No newline at end of file

From 7c3e34c00bb585b05104c13a03d3606427cb0457 Mon Sep 17 00:00:00 2001
From: Tan Li Hau <tanhauhau@users.noreply.github.com>
Date: Mon, 13 Jan 2020 04:42:45 +0800
Subject: [PATCH 02/82] fix hydrating each else (#4253)

---
 CHANGELOG.md                                      |  1 +
 .../compile/render_dom/wrappers/EachBlock.ts      | 13 +++++++++++++
 test/hydration/samples/each-else/_after.html      |  4 ++++
 test/hydration/samples/each-else/_before.html     |  4 ++++
 test/hydration/samples/each-else/main.svelte      | 15 +++++++++++++++
 5 files changed, 37 insertions(+)
 create mode 100644 test/hydration/samples/each-else/_after.html
 create mode 100644 test/hydration/samples/each-else/_before.html
 create mode 100644 test/hydration/samples/each-else/main.svelte

diff --git a/CHANGELOG.md b/CHANGELOG.md
index f6af419913..25c0aa2093 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,7 @@
 * Expose compiler version in dev events ([#4047](https://github.com/sveltejs/svelte/issues/4047))
 * Don't run actions before their element is in the document ([#4166](https://github.com/sveltejs/svelte/issues/4166))
 * Fix reactive assignments with destructuring and stores where the destructured value should be undefined ([#4170](https://github.com/sveltejs/svelte/issues/4170))
+* Fix hydrating `{:else}` in `{#each}` ([#4202](https://github.com/sveltejs/svelte/issues/4202))
 * Do not automatically declare variables in reactive declarations when assigning to a member expression ([#4212](https://github.com/sveltejs/svelte/issues/4212))
 
 ## 3.16.7
diff --git a/src/compiler/compile/render_dom/wrappers/EachBlock.ts b/src/compiler/compile/render_dom/wrappers/EachBlock.ts
index 5b13b486e6..4928b5a38c 100644
--- a/src/compiler/compile/render_dom/wrappers/EachBlock.ts
+++ b/src/compiler/compile/render_dom/wrappers/EachBlock.ts
@@ -264,10 +264,23 @@ export default class EachBlockWrapper extends Wrapper {
 			block.chunks.init.push(b`
 				if (!${this.vars.data_length}) {
 					${each_block_else} = ${this.else.block.name}(#ctx);
+				}
+			`);
+
+			block.chunks.create.push(b`
+				if (${each_block_else}) {
 					${each_block_else}.c();
 				}
 			`);
 
+			if (this.renderer.options.hydratable) {
+				block.chunks.claim.push(b`
+					if (${each_block_else}) {
+						${each_block_else}.l(${parent_nodes});
+					}
+				`);
+			}
+
 			block.chunks.mount.push(b`
 				if (${each_block_else}) {
 					${each_block_else}.m(${initial_mount_node}, ${initial_anchor_node});
diff --git a/test/hydration/samples/each-else/_after.html b/test/hydration/samples/each-else/_after.html
new file mode 100644
index 0000000000..7920500ec3
--- /dev/null
+++ b/test/hydration/samples/each-else/_after.html
@@ -0,0 +1,4 @@
+<h1>Hello, world</h1>
+<p>
+  weird
+</p>
\ No newline at end of file
diff --git a/test/hydration/samples/each-else/_before.html b/test/hydration/samples/each-else/_before.html
new file mode 100644
index 0000000000..7920500ec3
--- /dev/null
+++ b/test/hydration/samples/each-else/_before.html
@@ -0,0 +1,4 @@
+<h1>Hello, world</h1>
+<p>
+  weird
+</p>
\ No newline at end of file
diff --git a/test/hydration/samples/each-else/main.svelte b/test/hydration/samples/each-else/main.svelte
new file mode 100644
index 0000000000..64d3a37c58
--- /dev/null
+++ b/test/hydration/samples/each-else/main.svelte
@@ -0,0 +1,15 @@
+<script>
+	export let name = "world";
+	export let array = [];
+</script>
+
+<h1>Hello, {name}</h1>
+{#each array as elem}
+	<p>
+	item
+	</p>
+{:else}
+	<p>
+	weird
+	</p>
+{/each}

From ef56a70acbe484bf1be9787ae63ae5102ee275ea Mon Sep 17 00:00:00 2001
From: Tan Li Hau <tanhauhau@users.noreply.github.com>
Date: Tue, 14 Jan 2020 00:13:54 +0800
Subject: [PATCH 03/82] SSR should only render one <title> (#4250)

---
 CHANGELOG.md                                           |  1 +
 src/compiler/compile/render_ssr/handlers/Title.ts      |  6 ++++++
 src/runtime/internal/ssr.ts                            |  5 +++--
 .../samples/head-multiple-title/A.svelte               |  3 +++
 .../samples/head-multiple-title/B.svelte               |  3 +++
 .../samples/head-multiple-title/_expected-head.html    |  1 +
 .../samples/head-multiple-title/_expected.html         |  0
 .../samples/head-multiple-title/data.json              |  3 +++
 .../samples/head-multiple-title/main.svelte            | 10 ++++++++++
 9 files changed, 30 insertions(+), 2 deletions(-)
 create mode 100644 test/server-side-rendering/samples/head-multiple-title/A.svelte
 create mode 100644 test/server-side-rendering/samples/head-multiple-title/B.svelte
 create mode 100644 test/server-side-rendering/samples/head-multiple-title/_expected-head.html
 create mode 100644 test/server-side-rendering/samples/head-multiple-title/_expected.html
 create mode 100644 test/server-side-rendering/samples/head-multiple-title/data.json
 create mode 100644 test/server-side-rendering/samples/head-multiple-title/main.svelte

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 25c0aa2093..8d69c6194b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@
 * Fix reactive assignments with destructuring and stores where the destructured value should be undefined ([#4170](https://github.com/sveltejs/svelte/issues/4170))
 * Fix hydrating `{:else}` in `{#each}` ([#4202](https://github.com/sveltejs/svelte/issues/4202))
 * Do not automatically declare variables in reactive declarations when assigning to a member expression ([#4212](https://github.com/sveltejs/svelte/issues/4212))
+* Only render one `<title>` in SSR mode when multiple components provide one ([#4250](https://github.com/sveltejs/svelte/pull/4250))
 
 ## 3.16.7
 
diff --git a/src/compiler/compile/render_ssr/handlers/Title.ts b/src/compiler/compile/render_ssr/handlers/Title.ts
index 62d49d461a..f1f458ed5b 100644
--- a/src/compiler/compile/render_ssr/handlers/Title.ts
+++ b/src/compiler/compile/render_ssr/handlers/Title.ts
@@ -1,10 +1,16 @@
 import Renderer, { RenderOptions } from '../Renderer';
 import Title from '../../nodes/Title';
+import { x } from 'code-red';
 
 export default function(node: Title, renderer: Renderer, options: RenderOptions) {
+	renderer.push();
+
 	renderer.add_string(`<title>`);
 
 	renderer.render(node.children, options);
 
 	renderer.add_string(`</title>`);
+	const result = renderer.pop();
+
+	renderer.add_expression(x`($$result.title = ${result}, "")`);
 }
diff --git a/src/runtime/internal/ssr.ts b/src/runtime/internal/ssr.ts
index 274006f243..b032284d52 100644
--- a/src/runtime/internal/ssr.ts
+++ b/src/runtime/internal/ssr.ts
@@ -103,12 +103,13 @@ export function create_ssr_component(fn) {
 			on_destroy = [];
 
 			const result: {
+				title: string;
 				head: string;
 				css: Set<{
 					map: null;
 					code: string;
 				}>;
-			} = { head: '', css: new Set() };
+			} = { title: '', head: '', css: new Set() };
 
 			const html = $$render(result, props, {}, options);
 
@@ -120,7 +121,7 @@ export function create_ssr_component(fn) {
 					code: Array.from(result.css).map(css => css.code).join('\n'),
 					map: null // TODO
 				},
-				head: result.head
+				head: result.title + result.head
 			};
 		},
 
diff --git a/test/server-side-rendering/samples/head-multiple-title/A.svelte b/test/server-side-rendering/samples/head-multiple-title/A.svelte
new file mode 100644
index 0000000000..b139b4ff77
--- /dev/null
+++ b/test/server-side-rendering/samples/head-multiple-title/A.svelte
@@ -0,0 +1,3 @@
+<svelte:head>
+	<title>A</title>
+</svelte:head>
diff --git a/test/server-side-rendering/samples/head-multiple-title/B.svelte b/test/server-side-rendering/samples/head-multiple-title/B.svelte
new file mode 100644
index 0000000000..4a29ecb04c
--- /dev/null
+++ b/test/server-side-rendering/samples/head-multiple-title/B.svelte
@@ -0,0 +1,3 @@
+<svelte:head>
+	<title>B</title>
+</svelte:head>
diff --git a/test/server-side-rendering/samples/head-multiple-title/_expected-head.html b/test/server-side-rendering/samples/head-multiple-title/_expected-head.html
new file mode 100644
index 0000000000..af5c5feba4
--- /dev/null
+++ b/test/server-side-rendering/samples/head-multiple-title/_expected-head.html
@@ -0,0 +1 @@
+<title>B</title>
\ No newline at end of file
diff --git a/test/server-side-rendering/samples/head-multiple-title/_expected.html b/test/server-side-rendering/samples/head-multiple-title/_expected.html
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/test/server-side-rendering/samples/head-multiple-title/data.json b/test/server-side-rendering/samples/head-multiple-title/data.json
new file mode 100644
index 0000000000..eab238e816
--- /dev/null
+++ b/test/server-side-rendering/samples/head-multiple-title/data.json
@@ -0,0 +1,3 @@
+{
+	"adjective": "custom"
+}
\ No newline at end of file
diff --git a/test/server-side-rendering/samples/head-multiple-title/main.svelte b/test/server-side-rendering/samples/head-multiple-title/main.svelte
new file mode 100644
index 0000000000..fb9a70b923
--- /dev/null
+++ b/test/server-side-rendering/samples/head-multiple-title/main.svelte
@@ -0,0 +1,10 @@
+<script>
+	import A from './A.svelte';
+	import B from './B.svelte';
+</script>
+
+<svelte:head>
+	<title>Main</title>
+</svelte:head>
+<A />
+<B />

From e3d66869df5b75b81da6183c5d68cde53b2439aa Mon Sep 17 00:00:00 2001
From: Jesse Skinner <jesse@thefutureoftheweb.com>
Date: Mon, 13 Jan 2020 11:24:34 -0500
Subject: [PATCH 04/82] fix stringifying of attributes in presence of spread in
 SSR (#4247)

---
 src/runtime/internal/ssr.ts                          |  4 +---
 .../spread-attributes-white-space/_expected.html     |  8 ++++++++
 .../spread-attributes-white-space/main.svelte        | 12 ++++++++++++
 3 files changed, 21 insertions(+), 3 deletions(-)
 create mode 100644 test/server-side-rendering/samples/spread-attributes-white-space/_expected.html
 create mode 100644 test/server-side-rendering/samples/spread-attributes-white-space/main.svelte

diff --git a/src/runtime/internal/ssr.ts b/src/runtime/internal/ssr.ts
index b032284d52..646a81d817 100644
--- a/src/runtime/internal/ssr.ts
+++ b/src/runtime/internal/ssr.ts
@@ -25,9 +25,7 @@ export function spread(args, classes_to_add) {
 		else if (boolean_attributes.has(name.toLowerCase())) {
 			if (value) str += " " + name;
 		} else if (value != null) {
-			str += " " + name + "=" + JSON.stringify(String(value)
-				.replace(/"/g, '&#34;')
-				.replace(/'/g, '&#39;'));
+			str += ` ${name}="${String(value).replace(/"/g, '&#34;').replace(/'/g, '&#39;')}"`;
 		}
 	});
 
diff --git a/test/server-side-rendering/samples/spread-attributes-white-space/_expected.html b/test/server-side-rendering/samples/spread-attributes-white-space/_expected.html
new file mode 100644
index 0000000000..a73bb17e8c
--- /dev/null
+++ b/test/server-side-rendering/samples/spread-attributes-white-space/_expected.html
@@ -0,0 +1,8 @@
+<input value="
+	bar
+">
+
+<input class="
+	white
+	space
+">
\ No newline at end of file
diff --git a/test/server-side-rendering/samples/spread-attributes-white-space/main.svelte b/test/server-side-rendering/samples/spread-attributes-white-space/main.svelte
new file mode 100644
index 0000000000..6919d9ea54
--- /dev/null
+++ b/test/server-side-rendering/samples/spread-attributes-white-space/main.svelte
@@ -0,0 +1,12 @@
+<script>
+	let props = {
+		value: '\n\tbar\n',
+	};
+</script>
+
+<input {...props} />
+
+<input class="
+	white
+	space
+" {...({})}>

From d7d7ce1e6c4ab0166eb5f40e5f2dad6a49dd0fe3 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Mon, 13 Jan 2020 11:25:48 -0500
Subject: [PATCH 05/82] update changelog

---
 CHANGELOG.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8d69c6194b..a2db4470d1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@
 * Fix reactive assignments with destructuring and stores where the destructured value should be undefined ([#4170](https://github.com/sveltejs/svelte/issues/4170))
 * Fix hydrating `{:else}` in `{#each}` ([#4202](https://github.com/sveltejs/svelte/issues/4202))
 * Do not automatically declare variables in reactive declarations when assigning to a member expression ([#4212](https://github.com/sveltejs/svelte/issues/4212))
+* Fix stringifying of attributes in SSR mode when there are spread attributes ([#4240](https://github.com/sveltejs/svelte/issues/4240))
 * Only render one `<title>` in SSR mode when multiple components provide one ([#4250](https://github.com/sveltejs/svelte/pull/4250))
 
 ## 3.16.7

From b3582c7fb24572a6dfd58e2009925158a9a37233 Mon Sep 17 00:00:00 2001
From: Tan Li Hau <tanhauhau@users.noreply.github.com>
Date: Tue, 14 Jan 2020 00:55:55 +0800
Subject: [PATCH 06/82] fix hydrating <head> (#4082)

---
 CHANGELOG.md                                  |  1 +
 src/compiler/compile/css/Stylesheet.ts        | 10 +--------
 src/compiler/compile/nodes/Head.ts            |  6 ++++++
 .../compile/render_dom/wrappers/Head.ts       | 17 +++++++++++++--
 src/compiler/compile/render_ssr/Renderer.ts   |  1 +
 .../compile/render_ssr/handlers/Element.ts    |  4 ++++
 .../compile/render_ssr/handlers/Head.ts       |  7 ++++++-
 .../compile/render_ssr/handlers/Title.ts      |  2 +-
 src/compiler/compile/utils/hash.ts            |  8 +++++++
 src/runtime/internal/dom.ts                   |  4 ++++
 test/helpers.js                               |  1 +
 test/hydration/index.js                       | 21 +++++++++++++++++++
 .../head-meta-hydrate-duplicate/_after.html   |  1 +
 .../_after_head.html                          |  4 ++++
 .../head-meta-hydrate-duplicate/_before.html  |  1 +
 .../_before_head.html                         |  4 ++++
 .../head-meta-hydrate-duplicate/_config.js    |  5 +++++
 .../head-meta-hydrate-duplicate/main.svelte   |  8 +++++++
 .../_expected-head.html                       |  4 ++++
 .../_expected.html                            |  3 +++
 .../head-meta-hydrate-duplicate/main.svelte   |  8 +++++++
 .../head-multiple-title/_expected-head.html   |  2 +-
 .../samples/head-title/_expected-head.html    |  2 +-
 23 files changed, 109 insertions(+), 15 deletions(-)
 create mode 100644 src/compiler/compile/utils/hash.ts
 create mode 100644 test/hydration/samples/head-meta-hydrate-duplicate/_after.html
 create mode 100644 test/hydration/samples/head-meta-hydrate-duplicate/_after_head.html
 create mode 100644 test/hydration/samples/head-meta-hydrate-duplicate/_before.html
 create mode 100644 test/hydration/samples/head-meta-hydrate-duplicate/_before_head.html
 create mode 100644 test/hydration/samples/head-meta-hydrate-duplicate/_config.js
 create mode 100644 test/hydration/samples/head-meta-hydrate-duplicate/main.svelte
 create mode 100644 test/server-side-rendering/samples/head-meta-hydrate-duplicate/_expected-head.html
 create mode 100644 test/server-side-rendering/samples/head-meta-hydrate-duplicate/_expected.html
 create mode 100644 test/server-side-rendering/samples/head-meta-hydrate-duplicate/main.svelte

diff --git a/CHANGELOG.md b/CHANGELOG.md
index a2db4470d1..4bacc5c26b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+* Remove old `<head>` elements during hydration so they aren't duplicated ([#1607](https://github.com/sveltejs/svelte/issues/1607))
 * Prevent text input cursor jumping in Safari with one-way binding ([#3449](https://github.com/sveltejs/svelte/issues/3449))
 * Expose compiler version in dev events ([#4047](https://github.com/sveltejs/svelte/issues/4047))
 * Don't run actions before their element is in the document ([#4166](https://github.com/sveltejs/svelte/issues/4166))
diff --git a/src/compiler/compile/css/Stylesheet.ts b/src/compiler/compile/css/Stylesheet.ts
index 998a879687..246dab0f12 100644
--- a/src/compiler/compile/css/Stylesheet.ts
+++ b/src/compiler/compile/css/Stylesheet.ts
@@ -5,6 +5,7 @@ import Element from '../nodes/Element';
 import { Ast, TemplateNode } from '../../interfaces';
 import Component from '../Component';
 import { CssNode } from './interfaces';
+import hash from "../utils/hash";
 
 function remove_css_prefix(name: string): string {
 	return name.replace(/^-((webkit)|(moz)|(o)|(ms))-/, '');
@@ -37,15 +38,6 @@ function minify_declarations(
 	return c;
 }
 
-// https://github.com/darkskyapp/string-hash/blob/master/index.js
-function hash(str: string): string {
-	let hash = 5381;
-	let i = str.length;
-
-	while (i--) hash = ((hash << 5) - hash) ^ str.charCodeAt(i);
-	return (hash >>> 0).toString(36);
-}
-
 class Rule {
 	selectors: Selector[];
 	declarations: Declaration[];
diff --git a/src/compiler/compile/nodes/Head.ts b/src/compiler/compile/nodes/Head.ts
index 2c08dcd595..53e76d7a4d 100644
--- a/src/compiler/compile/nodes/Head.ts
+++ b/src/compiler/compile/nodes/Head.ts
@@ -1,9 +1,11 @@
 import Node from './shared/Node';
 import map_children from './shared/map_children';
+import hash from '../utils/hash';
 
 export default class Head extends Node {
 	type: 'Head';
 	children: any[]; // TODO
+	id: string;
 
 	constructor(component, parent, scope, info) {
 		super(component, parent, scope, info);
@@ -18,5 +20,9 @@ export default class Head extends Node {
 		this.children = map_children(component, parent, scope, info.children.filter(child => {
 			return (child.type !== 'Text' || /\S/.test(child.data));
 		}));
+
+		if (this.children.length > 0) {
+			this.id = `svelte-${hash(this.component.source.slice(this.start, this.end))}`;
+		}
 	}
 }
diff --git a/src/compiler/compile/render_dom/wrappers/Head.ts b/src/compiler/compile/render_dom/wrappers/Head.ts
index 188c26931a..e0b723d6dd 100644
--- a/src/compiler/compile/render_dom/wrappers/Head.ts
+++ b/src/compiler/compile/render_dom/wrappers/Head.ts
@@ -3,11 +3,12 @@ import Renderer from '../Renderer';
 import Block from '../Block';
 import Head from '../../nodes/Head';
 import FragmentWrapper from './Fragment';
-import { x } from 'code-red';
+import { x, b } from 'code-red';
 import { Identifier } from 'estree';
 
 export default class HeadWrapper extends Wrapper {
 	fragment: FragmentWrapper;
+	node: Head;
 
 	constructor(
 		renderer: Renderer,
@@ -32,6 +33,18 @@ export default class HeadWrapper extends Wrapper {
 	}
 
 	render(block: Block, _parent_node: Identifier, _parent_nodes: Identifier) {
-		this.fragment.render(block, x`@_document.head` as unknown as Identifier, x`#nodes` as unknown as Identifier);
+		let nodes;
+		if (this.renderer.options.hydratable && this.fragment.nodes.length) {
+			nodes = block.get_unique_name('head_nodes');
+			block.chunks.claim.push(b`const ${nodes} = @query_selector_all('[data-svelte="${this.node.id}"]', @_document.head);`);
+		}
+
+		this.fragment.render(block, x`@_document.head` as unknown as Identifier, nodes);
+
+		if (nodes && this.renderer.options.hydratable) {
+			block.chunks.claim.push(
+				b`${nodes}.forEach(@detach);`
+			);
+		}
 	}
 }
diff --git a/src/compiler/compile/render_ssr/Renderer.ts b/src/compiler/compile/render_ssr/Renderer.ts
index 00a7ee2fb5..fb9216327c 100644
--- a/src/compiler/compile/render_ssr/Renderer.ts
+++ b/src/compiler/compile/render_ssr/Renderer.ts
@@ -41,6 +41,7 @@ const handlers: Record<string, Handler> = {
 
 export interface RenderOptions extends CompileOptions{
 	locate: (c: number) => { line: number; column: number };
+	head_id?: string;
 }
 
 export default class Renderer {
diff --git a/src/compiler/compile/render_ssr/handlers/Element.ts b/src/compiler/compile/render_ssr/handlers/Element.ts
index 81b8801686..4c1eca8a9d 100644
--- a/src/compiler/compile/render_ssr/handlers/Element.ts
+++ b/src/compiler/compile/render_ssr/handlers/Element.ts
@@ -124,6 +124,10 @@ export default function(node: Element, renderer: Renderer, options: RenderOption
 		}
 	});
 
+	if (options.head_id) {
+		renderer.add_string(` data-svelte="${options.head_id}"`);
+	}
+
 	renderer.add_string('>');
 
 	if (node_contents !== undefined) {
diff --git a/src/compiler/compile/render_ssr/handlers/Head.ts b/src/compiler/compile/render_ssr/handlers/Head.ts
index d457942922..456e5c279b 100644
--- a/src/compiler/compile/render_ssr/handlers/Head.ts
+++ b/src/compiler/compile/render_ssr/handlers/Head.ts
@@ -3,8 +3,13 @@ import Head from '../../nodes/Head';
 import { x } from 'code-red';
 
 export default function(node: Head, renderer: Renderer, options: RenderOptions) {
+	const head_options = {
+		...options,
+		head_id: node.id
+	};
+
 	renderer.push();
-	renderer.render(node.children, options);
+	renderer.render(node.children, head_options);
 	const result = renderer.pop();
 
 	renderer.add_expression(x`($$result.head += ${result}, "")`);
diff --git a/src/compiler/compile/render_ssr/handlers/Title.ts b/src/compiler/compile/render_ssr/handlers/Title.ts
index f1f458ed5b..e93ae13d66 100644
--- a/src/compiler/compile/render_ssr/handlers/Title.ts
+++ b/src/compiler/compile/render_ssr/handlers/Title.ts
@@ -5,7 +5,7 @@ import { x } from 'code-red';
 export default function(node: Title, renderer: Renderer, options: RenderOptions) {
 	renderer.push();
 
-	renderer.add_string(`<title>`);
+	renderer.add_string(`<title data-svelte="${options.head_id}">`);
 
 	renderer.render(node.children, options);
 
diff --git a/src/compiler/compile/utils/hash.ts b/src/compiler/compile/utils/hash.ts
new file mode 100644
index 0000000000..7ac892611b
--- /dev/null
+++ b/src/compiler/compile/utils/hash.ts
@@ -0,0 +1,8 @@
+// https://github.com/darkskyapp/string-hash/blob/master/index.js
+export default function hash(str: string): string {
+	let hash = 5381;
+	let i = str.length;
+
+	while (i--) hash = ((hash << 5) - hash) ^ str.charCodeAt(i);
+	return (hash >>> 0).toString(36);
+}
\ No newline at end of file
diff --git a/src/runtime/internal/dom.ts b/src/runtime/internal/dom.ts
index c641315bc3..f9e89f41b9 100644
--- a/src/runtime/internal/dom.ts
+++ b/src/runtime/internal/dom.ts
@@ -273,6 +273,10 @@ export function custom_event<T=any>(type: string, detail?: T) {
 	return e;
 }
 
+export function query_selector_all(selector: string, parent: HTMLElement = document.body) {
+	return Array.from(parent.querySelectorAll(selector));
+}
+
 export class HtmlTag {
 	e: HTMLElement;
 	n: ChildNode[];
diff --git a/test/helpers.js b/test/helpers.js
index 2a03e0f436..5e9428243b 100644
--- a/test/helpers.js
+++ b/test/helpers.js
@@ -68,6 +68,7 @@ window.scrollTo = function(pageXOffset, pageYOffset) {
 
 export function env() {
 	window.document.title = '';
+	window.document.head.innerHTML = '';
 	window.document.body.innerHTML = '<main></main>';
 
 	return window;
diff --git a/test/hydration/index.js b/test/hydration/index.js
index a0bfd6de4b..f57a0cdc1a 100644
--- a/test/hydration/index.js
+++ b/test/hydration/index.js
@@ -67,8 +67,16 @@ describe('hydration', () => {
 				}
 
 				const target = window.document.body;
+				const head = window.document.head;
+
 				target.innerHTML = fs.readFileSync(`${cwd}/_before.html`, 'utf-8');
 
+				let before_head;
+				try {
+					before_head = fs.readFileSync(`${cwd}/_before_head.html`, 'utf-8');
+					head.innerHTML = before_head;
+				} catch (err) {}
+
 				const snapshot = config.snapshot ? config.snapshot(target) : {};
 
 				const component = new SvelteComponent({
@@ -88,6 +96,19 @@ describe('hydration', () => {
 					}
 				}
 
+				if (before_head) {
+					try {
+						assert.htmlEqual(head.innerHTML, fs.readFileSync(`${cwd}/_after_head.html`, 'utf-8'));
+					} catch (error) {
+						if (shouldUpdateExpected()) {
+							fs.writeFileSync(`${cwd}/_after_head.html`, head.innerHTML);
+							console.log(`Updated ${cwd}/_after_head.html.`);
+						} else {
+							throw error;
+						}
+					}
+				}
+
 				if (config.test) {
 					config.test(assert, target, snapshot, component, window);
 				} else {
diff --git a/test/hydration/samples/head-meta-hydrate-duplicate/_after.html b/test/hydration/samples/head-meta-hydrate-duplicate/_after.html
new file mode 100644
index 0000000000..3e5b375f0a
--- /dev/null
+++ b/test/hydration/samples/head-meta-hydrate-duplicate/_after.html
@@ -0,0 +1 @@
+<div>Just a dummy page.</div>
\ No newline at end of file
diff --git a/test/hydration/samples/head-meta-hydrate-duplicate/_after_head.html b/test/hydration/samples/head-meta-hydrate-duplicate/_after_head.html
new file mode 100644
index 0000000000..10cf2c8b9a
--- /dev/null
+++ b/test/hydration/samples/head-meta-hydrate-duplicate/_after_head.html
@@ -0,0 +1,4 @@
+<title>Some Title</title>
+<link href="/" rel="canonical">
+<meta content="some description" name="description">
+<meta content="some keywords" name="keywords">
\ No newline at end of file
diff --git a/test/hydration/samples/head-meta-hydrate-duplicate/_before.html b/test/hydration/samples/head-meta-hydrate-duplicate/_before.html
new file mode 100644
index 0000000000..3e5b375f0a
--- /dev/null
+++ b/test/hydration/samples/head-meta-hydrate-duplicate/_before.html
@@ -0,0 +1 @@
+<div>Just a dummy page.</div>
\ No newline at end of file
diff --git a/test/hydration/samples/head-meta-hydrate-duplicate/_before_head.html b/test/hydration/samples/head-meta-hydrate-duplicate/_before_head.html
new file mode 100644
index 0000000000..d2f218fb8d
--- /dev/null
+++ b/test/hydration/samples/head-meta-hydrate-duplicate/_before_head.html
@@ -0,0 +1,4 @@
+<title data-svelte="svelte-1s8aodm">Some Title</title>
+<link rel="canonical" href="/" data-svelte="svelte-1s8aodm">
+<meta name="description" content="some description" data-svelte="svelte-1s8aodm">
+<meta name="keywords" content="some keywords" data-svelte="svelte-1s8aodm">
\ No newline at end of file
diff --git a/test/hydration/samples/head-meta-hydrate-duplicate/_config.js b/test/hydration/samples/head-meta-hydrate-duplicate/_config.js
new file mode 100644
index 0000000000..482efd564d
--- /dev/null
+++ b/test/hydration/samples/head-meta-hydrate-duplicate/_config.js
@@ -0,0 +1,5 @@
+export default {
+	test(assert, target, snapshot, component, window) {
+		assert.equal(window.document.querySelectorAll('meta').length, 2);
+	}
+};
diff --git a/test/hydration/samples/head-meta-hydrate-duplicate/main.svelte b/test/hydration/samples/head-meta-hydrate-duplicate/main.svelte
new file mode 100644
index 0000000000..1a8b125dd2
--- /dev/null
+++ b/test/hydration/samples/head-meta-hydrate-duplicate/main.svelte
@@ -0,0 +1,8 @@
+<svelte:head>
+  <title>Some Title</title>
+  <link rel="canonical" href="/">
+  <meta name="description" content="some description">
+  <meta name="keywords" content="some keywords">
+</svelte:head>
+
+<div>Just a dummy page.</div>
\ No newline at end of file
diff --git a/test/server-side-rendering/samples/head-meta-hydrate-duplicate/_expected-head.html b/test/server-side-rendering/samples/head-meta-hydrate-duplicate/_expected-head.html
new file mode 100644
index 0000000000..d2f218fb8d
--- /dev/null
+++ b/test/server-side-rendering/samples/head-meta-hydrate-duplicate/_expected-head.html
@@ -0,0 +1,4 @@
+<title data-svelte="svelte-1s8aodm">Some Title</title>
+<link rel="canonical" href="/" data-svelte="svelte-1s8aodm">
+<meta name="description" content="some description" data-svelte="svelte-1s8aodm">
+<meta name="keywords" content="some keywords" data-svelte="svelte-1s8aodm">
\ No newline at end of file
diff --git a/test/server-side-rendering/samples/head-meta-hydrate-duplicate/_expected.html b/test/server-side-rendering/samples/head-meta-hydrate-duplicate/_expected.html
new file mode 100644
index 0000000000..a469e618fa
--- /dev/null
+++ b/test/server-side-rendering/samples/head-meta-hydrate-duplicate/_expected.html
@@ -0,0 +1,3 @@
+
+
+<div>Just a dummy page.</div>
\ No newline at end of file
diff --git a/test/server-side-rendering/samples/head-meta-hydrate-duplicate/main.svelte b/test/server-side-rendering/samples/head-meta-hydrate-duplicate/main.svelte
new file mode 100644
index 0000000000..1a8b125dd2
--- /dev/null
+++ b/test/server-side-rendering/samples/head-meta-hydrate-duplicate/main.svelte
@@ -0,0 +1,8 @@
+<svelte:head>
+  <title>Some Title</title>
+  <link rel="canonical" href="/">
+  <meta name="description" content="some description">
+  <meta name="keywords" content="some keywords">
+</svelte:head>
+
+<div>Just a dummy page.</div>
\ No newline at end of file
diff --git a/test/server-side-rendering/samples/head-multiple-title/_expected-head.html b/test/server-side-rendering/samples/head-multiple-title/_expected-head.html
index af5c5feba4..7147550839 100644
--- a/test/server-side-rendering/samples/head-multiple-title/_expected-head.html
+++ b/test/server-side-rendering/samples/head-multiple-title/_expected-head.html
@@ -1 +1 @@
-<title>B</title>
\ No newline at end of file
+<title data-svelte="svelte-1csszk6">B</title>
\ No newline at end of file
diff --git a/test/server-side-rendering/samples/head-title/_expected-head.html b/test/server-side-rendering/samples/head-title/_expected-head.html
index 7d696352f9..6e73e671e6 100644
--- a/test/server-side-rendering/samples/head-title/_expected-head.html
+++ b/test/server-side-rendering/samples/head-title/_expected-head.html
@@ -1 +1 @@
-<title>a custom title</title>
\ No newline at end of file
+<title data-svelte="svelte-135agoq">a custom title</title>
\ No newline at end of file

From c97e8f81db1f77a623716c9bedaa382def1d653c Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Mon, 13 Jan 2020 11:59:06 -0500
Subject: [PATCH 07/82] -> v3.17.0

---
 CHANGELOG.md      | 2 +-
 package-lock.json | 2 +-
 package.json      | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4bacc5c26b..32012876a3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,6 @@
 # Svelte changelog
 
-## Unreleased
+## 3.17.0
 
 * Remove old `<head>` elements during hydration so they aren't duplicated ([#1607](https://github.com/sveltejs/svelte/issues/1607))
 * Prevent text input cursor jumping in Safari with one-way binding ([#3449](https://github.com/sveltejs/svelte/issues/3449))
diff --git a/package-lock.json b/package-lock.json
index 6dc707c8d5..9ee0b53af6 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "svelte",
-  "version": "3.16.7",
+  "version": "3.17.0",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
diff --git a/package.json b/package.json
index 9c249f499f..2c5edf9437 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "svelte",
-  "version": "3.16.7",
+  "version": "3.17.0",
   "description": "Cybernetically enhanced web apps",
   "module": "index.mjs",
   "main": "index",

From 7494509dfd67011f0cb73aa8b77c729b3dab46f5 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Tue, 14 Jan 2020 12:11:52 -0500
Subject: [PATCH 08/82] only attach SSR <head> markers when hydratable: true
 (#4260)

---
 CHANGELOG.md                                  |  4 +++
 site/content/docs/03-run-time.md              |  2 +-
 site/content/docs/04-compile-time.md          |  2 +-
 .../compile/render_ssr/handlers/Element.ts    |  2 +-
 .../compile/render_ssr/handlers/Title.ts      |  6 +++-
 test/helpers.js                               |  6 ++++
 test/runtime/index.js                         |  7 ++--
 test/server-side-rendering/index.js           | 34 ++++++++++++-------
 .../head-meta-hydrate-duplicate/_config.js    |  5 +++
 .../head-multiple-title/_expected-head.html   |  2 +-
 .../samples/head-title/_expected-head.html    |  2 +-
 11 files changed, 48 insertions(+), 24 deletions(-)
 create mode 100644 test/server-side-rendering/samples/head-meta-hydrate-duplicate/_config.js

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 32012876a3..480c145a95 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Svelte changelog
 
+## Unreleased
+
+* Only attach SSR mode markers to a component's `<head>` elements when compiling with `hydratable: true` ([#4258](https://github.com/sveltejs/svelte/issues/4258))
+
 ## 3.17.0
 
 * Remove old `<head>` elements during hydration so they aren't duplicated ([#1607](https://github.com/sveltejs/svelte/issues/1607))
diff --git a/site/content/docs/03-run-time.md b/site/content/docs/03-run-time.md
index e1509cf4d1..c75ec694d9 100644
--- a/site/content/docs/03-run-time.md
+++ b/site/content/docs/03-run-time.md
@@ -887,7 +887,7 @@ Existing children of `target` are left where they are.
 
 ---
 
-The `hydrate` option instructs Svelte to upgrade existing DOM (usually from server-side rendering) rather than creating new elements. It will only work if the component was compiled with the [`hydratable: true` option](docs#svelte_compile).
+The `hydrate` option instructs Svelte to upgrade existing DOM (usually from server-side rendering) rather than creating new elements. It will only work if the component was compiled with the [`hydratable: true` option](docs#svelte_compile). Hydration of `<head>` elements only works properly if the server-side rendering code was also compiled with `hydratable: true`, which adds a marker to each element in the `<head>` so that the component knows which elements it's responsible for removing during hydration.
 
 Whereas children of `target` are normally left alone, `hydrate: true` will cause any children to be removed. For that reason, the `anchor` option cannot be used alongside `hydrate: true`.
 
diff --git a/site/content/docs/04-compile-time.md b/site/content/docs/04-compile-time.md
index e9126ccf13..f753b2fcfe 100644
--- a/site/content/docs/04-compile-time.md
+++ b/site/content/docs/04-compile-time.md
@@ -68,7 +68,7 @@ The following options can be passed to the compiler. None are required:
 | `generate` | `"dom"` | If `"dom"`, Svelte emits a JavaScript class for mounting to the DOM. If `"ssr"`, Svelte emits an object with a `render` method suitable for server-side rendering. If `false`, no JavaScript or CSS is returned; just metadata.
 | `dev` | `false` | If `true`, causes extra code to be added to components that will perform runtime checks and provide debugging information during development.
 | `immutable` | `false` | If `true`, tells the compiler that you promise not to mutate any objects. This allows it to be less conservative about checking whether values have changed.
-| `hydratable` | `false` | If `true`, enables the `hydrate: true` runtime option, which allows a component to upgrade existing DOM rather than creating new DOM from scratch.
+| `hydratable` | `false` | If `true` when generating DOM code, enables the `hydrate: true` runtime option, which allows a component to upgrade existing DOM rather than creating new DOM from scratch. When generating SSR code, this adds markers to `<head>` elements so that hydration knows which to replace.
 | `legacy` | `false` | If `true`, generates code that will work in IE9 and IE10, which don't support things like `element.dataset`.
 | `accessors` | `false` | If `true`, getters and setters will be created for the component's props. If `false`, they will only be created for readonly exported values (i.e. those declared with `const`, `class` and `function`). If compiling with `customElement: true` this option defaults to `true`.
 | `customElement` | `false` | If `true`, tells the compiler to generate a custom element constructor instead of a regular Svelte component.
diff --git a/src/compiler/compile/render_ssr/handlers/Element.ts b/src/compiler/compile/render_ssr/handlers/Element.ts
index 4c1eca8a9d..e0982a0415 100644
--- a/src/compiler/compile/render_ssr/handlers/Element.ts
+++ b/src/compiler/compile/render_ssr/handlers/Element.ts
@@ -124,7 +124,7 @@ export default function(node: Element, renderer: Renderer, options: RenderOption
 		}
 	});
 
-	if (options.head_id) {
+	if (options.hydratable && options.head_id) {
 		renderer.add_string(` data-svelte="${options.head_id}"`);
 	}
 
diff --git a/src/compiler/compile/render_ssr/handlers/Title.ts b/src/compiler/compile/render_ssr/handlers/Title.ts
index e93ae13d66..a3f271ab1b 100644
--- a/src/compiler/compile/render_ssr/handlers/Title.ts
+++ b/src/compiler/compile/render_ssr/handlers/Title.ts
@@ -5,7 +5,11 @@ import { x } from 'code-red';
 export default function(node: Title, renderer: Renderer, options: RenderOptions) {
 	renderer.push();
 
-	renderer.add_string(`<title data-svelte="${options.head_id}">`);
+	renderer.add_string('<title');
+	if (options.hydratable && options.head_id) {
+		renderer.add_string(` data-svelte="${options.head_id}"`);
+	}
+	renderer.add_string('>');
 
 	renderer.render(node.children, options);
 
diff --git a/test/helpers.js b/test/helpers.js
index 5e9428243b..a764d43f96 100644
--- a/test/helpers.js
+++ b/test/helpers.js
@@ -45,6 +45,12 @@ export function tryToReadFile(file) {
 	}
 }
 
+export function cleanRequireCache() {
+	Object.keys(require.cache)
+		.filter(x => x.endsWith('.svelte'))
+		.forEach(file => delete require.cache[file]);
+}
+
 const virtualConsole = new jsdom.VirtualConsole();
 virtualConsole.sendTo(console);
 
diff --git a/test/runtime/index.js b/test/runtime/index.js
index df02cabcb4..f070eb8185 100644
--- a/test/runtime/index.js
+++ b/test/runtime/index.js
@@ -10,6 +10,7 @@ import {
 	showOutput,
 	loadConfig,
 	loadSvelte,
+	cleanRequireCache,
 	env,
 	setupHtmlEqual,
 	mkdirp
@@ -79,11 +80,7 @@ describe("runtime", () => {
 			compileOptions.immutable = config.immutable;
 			compileOptions.accessors = 'accessors' in config ? config.accessors : true;
 
-			Object.keys(require.cache)
-				.filter(x => x.endsWith('.svelte'))
-				.forEach(file => {
-					delete require.cache[file];
-				});
+			cleanRequireCache();
 
 			let mod;
 			let SvelteComponent;
diff --git a/test/server-side-rendering/index.js b/test/server-side-rendering/index.js
index a56a4ddaed..ee1319845d 100644
--- a/test/server-side-rendering/index.js
+++ b/test/server-side-rendering/index.js
@@ -9,6 +9,7 @@ import {
 	loadSvelte,
 	setupHtmlEqual,
 	tryToLoadJson,
+	cleanRequireCache,
 	shouldUpdateExpected,
 	mkdirp
 } from "../helpers.js";
@@ -27,11 +28,6 @@ let compile = null;
 
 describe("ssr", () => {
 	before(() => {
-		require("../../register")({
-			extensions: ['.svelte', '.html'],
-			sveltePath
-		});
-
 		compile = loadSvelte(true).compile;
 
 		return setupHtmlEqual();
@@ -40,9 +36,11 @@ describe("ssr", () => {
 	fs.readdirSync(`${__dirname}/samples`).forEach(dir => {
 		if (dir[0] === ".") return;
 
+		const config = loadConfig(`${__dirname}/samples/${dir}/_config.js`);
+
 		// add .solo to a sample directory name to only run that test, or
 		// .show to always show the output. or both
-		const solo = /\.solo/.test(dir);
+		const solo = config.solo || /\.solo/.test(dir);
 		const show = /\.show/.test(dir);
 
 		if (solo && process.env.CI) {
@@ -51,6 +49,18 @@ describe("ssr", () => {
 
 		(solo ? it.only : it)(dir, () => {
 			dir = path.resolve(`${__dirname}/samples`, dir);
+
+			cleanRequireCache();
+
+			const compileOptions = {
+				sveltePath,
+				...config.compileOptions,
+				generate: 'ssr',
+				format: 'cjs'
+			};
+
+			require("../../register")(compileOptions);
+
 			try {
 				const Component = require(`${dir}/main.svelte`).default;
 
@@ -133,18 +143,16 @@ describe("ssr", () => {
 		(config.skip ? it.skip : solo ? it.only : it)(dir, () => {
 			const cwd = path.resolve("test/runtime/samples", dir);
 
-			Object.keys(require.cache)
-				.filter(x => x.endsWith('.svelte'))
-				.forEach(file => {
-					delete require.cache[file];
-				});
+			cleanRequireCache();
 
 			delete global.window;
 
-			const compileOptions = Object.assign({ sveltePath }, config.compileOptions, {
+			const compileOptions = {
+				sveltePath,
+				...config.compileOptions,
 				generate: 'ssr',
 				format: 'cjs'
-			});
+			};
 
 			require("../../register")(compileOptions);
 
diff --git a/test/server-side-rendering/samples/head-meta-hydrate-duplicate/_config.js b/test/server-side-rendering/samples/head-meta-hydrate-duplicate/_config.js
new file mode 100644
index 0000000000..ae9b250f86
--- /dev/null
+++ b/test/server-side-rendering/samples/head-meta-hydrate-duplicate/_config.js
@@ -0,0 +1,5 @@
+export default {
+	compileOptions: {
+		hydratable: true
+	}
+};
diff --git a/test/server-side-rendering/samples/head-multiple-title/_expected-head.html b/test/server-side-rendering/samples/head-multiple-title/_expected-head.html
index 7147550839..af5c5feba4 100644
--- a/test/server-side-rendering/samples/head-multiple-title/_expected-head.html
+++ b/test/server-side-rendering/samples/head-multiple-title/_expected-head.html
@@ -1 +1 @@
-<title data-svelte="svelte-1csszk6">B</title>
\ No newline at end of file
+<title>B</title>
\ No newline at end of file
diff --git a/test/server-side-rendering/samples/head-title/_expected-head.html b/test/server-side-rendering/samples/head-title/_expected-head.html
index 6e73e671e6..7d696352f9 100644
--- a/test/server-side-rendering/samples/head-title/_expected-head.html
+++ b/test/server-side-rendering/samples/head-title/_expected-head.html
@@ -1 +1 @@
-<title data-svelte="svelte-135agoq">a custom title</title>
\ No newline at end of file
+<title>a custom title</title>
\ No newline at end of file

From 4e812a95e9abce3d68c53b33ad86fb91bbbe4773 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Tue, 14 Jan 2020 12:16:52 -0500
Subject: [PATCH 09/82] -> v3.17.1

---
 .vscode/settings.json | 1 +
 CHANGELOG.md          | 2 +-
 package.json          | 2 +-
 3 files changed, 3 insertions(+), 2 deletions(-)
 create mode 100644 .vscode/settings.json

diff --git a/.vscode/settings.json b/.vscode/settings.json
new file mode 100644
index 0000000000..1fe67481c7
--- /dev/null
+++ b/.vscode/settings.json
@@ -0,0 +1 @@
+{"files.insertFinalNewline":false}
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 480c145a95..dce6d47858 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,6 @@
 # Svelte changelog
 
-## Unreleased
+## 3.17.1
 
 * Only attach SSR mode markers to a component's `<head>` elements when compiling with `hydratable: true` ([#4258](https://github.com/sveltejs/svelte/issues/4258))
 
diff --git a/package.json b/package.json
index 2c5edf9437..c7ac32f3ae 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "svelte",
-  "version": "3.17.0",
+  "version": "3.17.1",
   "description": "Cybernetically enhanced web apps",
   "module": "index.mjs",
   "main": "index",

From bfff7a9d0e67804e7a0db04ed4fb4b9a6078d0ec Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Tue, 14 Jan 2020 16:03:20 -0500
Subject: [PATCH 10/82] oops

---
 .vscode/settings.json | 1 -
 1 file changed, 1 deletion(-)
 delete mode 100644 .vscode/settings.json

diff --git a/.vscode/settings.json b/.vscode/settings.json
deleted file mode 100644
index 1fe67481c7..0000000000
--- a/.vscode/settings.json
+++ /dev/null
@@ -1 +0,0 @@
-{"files.insertFinalNewline":false}

From 8b9b2c266e55c7a3e589a32cecf8f208e430c10a Mon Sep 17 00:00:00 2001
From: Tan Li Hau <tanhauhau@users.noreply.github.com>
Date: Thu, 16 Jan 2020 22:25:12 +0800
Subject: [PATCH 11/82] fix allow let scoped to root element (#4266)

---
 CHANGELOG.md                                  |  4 +++
 src/compiler/compile/nodes/Element.ts         | 31 +++++++++----------
 .../samples/component-slot-let-g/A.svelte     |  5 +++
 .../samples/component-slot-let-g/_config.js   | 22 +++++++++++++
 .../samples/component-slot-let-g/main.svelte  | 17 ++++++++++
 5 files changed, 63 insertions(+), 16 deletions(-)
 create mode 100644 test/runtime/samples/component-slot-let-g/A.svelte
 create mode 100644 test/runtime/samples/component-slot-let-g/_config.js
 create mode 100644 test/runtime/samples/component-slot-let-g/main.svelte

diff --git a/CHANGELOG.md b/CHANGELOG.md
index dce6d47858..1f93815185 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Svelte changelog
 
+## Unreleased
+
+* Allow access to `let:` variables in sibling attributes on slot root ([#4173](https://github.com/sveltejs/svelte/issues/4173))
+
 ## 3.17.1
 
 * Only attach SSR mode markers to a component's `<head>` elements when compiling with `hydratable: true` ([#4258](https://github.com/sveltejs/svelte/issues/4258))
diff --git a/src/compiler/compile/nodes/Element.ts b/src/compiler/compile/nodes/Element.ts
index a3b8dc7286..e8108858c5 100644
--- a/src/compiler/compile/nodes/Element.ts
+++ b/src/compiler/compile/nodes/Element.ts
@@ -151,6 +151,11 @@ export default class Element extends Node {
 			}
 		}
 
+		const has_let = info.attributes.some(node => node.type === 'Let');
+		if (has_let) {
+			scope = scope.child();
+		}
+
 		// Binding relies on Attribute, defer its evaluation
 		const order = ['Binding']; // everything else is -1
 		info.attributes.sort((a, b) => order.indexOf(a.type) - order.indexOf(b.type));
@@ -181,9 +186,16 @@ export default class Element extends Node {
 					this.handlers.push(new EventHandler(component, this, scope, node));
 					break;
 
-				case 'Let':
-					this.lets.push(new Let(component, this, scope, node));
+				case 'Let': {
+					const l = new Let(component, this, scope, node);
+					this.lets.push(l);
+					const dependencies = new Set([l.name.name]);
+
+					l.names.forEach(name => {
+						scope.add(name, dependencies, this);
+					});
 					break;
+				}
 
 				case 'Transition':
 				{
@@ -202,20 +214,7 @@ export default class Element extends Node {
 			}
 		});
 
-		if (this.lets.length > 0) {
-			this.scope = scope.child();
-
-			this.lets.forEach(l => {
-				const dependencies = new Set([l.name.name]);
-
-				l.names.forEach(name => {
-					this.scope.add(name, dependencies, this);
-				});
-			});
-		} else {
-			this.scope = scope;
-		}
-
+		this.scope = scope;
 		this.children = map_children(component, this, this.scope, info.children);
 
 		this.validate();
diff --git a/test/runtime/samples/component-slot-let-g/A.svelte b/test/runtime/samples/component-slot-let-g/A.svelte
new file mode 100644
index 0000000000..4f4ac95014
--- /dev/null
+++ b/test/runtime/samples/component-slot-let-g/A.svelte
@@ -0,0 +1,5 @@
+<script>
+	export let x;
+</script>
+
+<slot name="foo" reflected={x}/>
\ No newline at end of file
diff --git a/test/runtime/samples/component-slot-let-g/_config.js b/test/runtime/samples/component-slot-let-g/_config.js
new file mode 100644
index 0000000000..aaa9895ea8
--- /dev/null
+++ b/test/runtime/samples/component-slot-let-g/_config.js
@@ -0,0 +1,22 @@
+export default {
+	html: `
+		<span slot="foo" class="1">1</span>
+		0
+	`,
+	async test({ assert, target, component, window }) {
+		component.x = 2;
+
+		assert.htmlEqual(target.innerHTML, `
+			<span slot="foo" class="2">2</span>
+			0
+		`);
+
+		const span = target.querySelector('span');
+		await span.dispatchEvent(new window.MouseEvent('click'));
+
+		assert.htmlEqual(target.innerHTML, `
+			<span slot="foo" class="2">2</span>
+			2
+		`);
+	}
+};
diff --git a/test/runtime/samples/component-slot-let-g/main.svelte b/test/runtime/samples/component-slot-let-g/main.svelte
new file mode 100644
index 0000000000..e7d4890e6b
--- /dev/null
+++ b/test/runtime/samples/component-slot-let-g/main.svelte
@@ -0,0 +1,17 @@
+<script>
+	import A from './A.svelte';
+	export let x = 1;
+	let y = 0;
+</script>
+
+<A {x}>
+	<span 
+		on:click={() => y = reflected}
+		slot="foo"
+		let:reflected
+		class={reflected}
+	>
+		{reflected}
+	</span>
+</A>
+{ y }
\ No newline at end of file

From 2fd593f9d55d242cfcd4a6aafa09ce919d05ba7c Mon Sep 17 00:00:00 2001
From: John Muhl <johnmuhl@users.noreply.github.com>
Date: Thu, 16 Jan 2020 20:27:43 -0600
Subject: [PATCH 12/82] Add more globals

---
 src/compiler/utils/names.ts | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/compiler/utils/names.ts b/src/compiler/utils/names.ts
index 88d4d4a319..02cc12e087 100644
--- a/src/compiler/utils/names.ts
+++ b/src/compiler/utils/names.ts
@@ -5,6 +5,8 @@ export const globals = new Set([
 	'alert',
 	'Array',
 	'Boolean',
+	'clearInterval',
+	'clearTimeout',
 	'confirm',
 	'console',
 	'Date',
@@ -16,6 +18,9 @@ export const globals = new Set([
 	'Error',
 	'EvalError',
 	'Event',
+	'fetch',
+	'global',
+	'globalThis',
 	'history',
 	'Infinity',
 	'InternalError',
@@ -41,11 +46,14 @@ export const globals = new Set([
 	'RegExp',
 	'sessionStorage',
 	'Set',
+	'setInterval',
+	'setTimeout',
 	'String',
 	'SyntaxError',
 	'TypeError',
 	'undefined',
 	'URIError',
+	'URL',
 	'window'
 ]);
 

From 1438994bd4f51633ba5c869c26d16be2e8224213 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Thu, 16 Jan 2020 22:13:41 -0500
Subject: [PATCH 13/82] update changelog

---
 CHANGELOG.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1f93815185..f833dfae2a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@
 ## Unreleased
 
 * Allow access to `let:` variables in sibling attributes on slot root ([#4173](https://github.com/sveltejs/svelte/issues/4173))
+* Add some more known globals ([#4276](https://github.com/sveltejs/svelte/pull/4276))
 
 ## 3.17.1
 

From 527ddea289196f3dc4c8ca5e0d001b9c7e5ce2a0 Mon Sep 17 00:00:00 2001
From: Tan Li Hau <lhtan93@gmail.com>
Date: Fri, 17 Jan 2020 08:07:48 +0800
Subject: [PATCH 14/82] disallow binding variables declared in await and catch

---
 src/compiler/compile/nodes/Binding.ts                    | 7 +++++++
 src/compiler/compile/nodes/shared/TemplateScope.ts       | 5 +++++
 test/validator/samples/binding-await-catch/errors.json   | 9 +++++++++
 test/validator/samples/binding-await-catch/input.svelte  | 7 +++++++
 test/validator/samples/binding-await-then-2/errors.json  | 9 +++++++++
 test/validator/samples/binding-await-then-2/input.svelte | 7 +++++++
 test/validator/samples/binding-await-then/errors.json    | 9 +++++++++
 test/validator/samples/binding-await-then/input.svelte   | 6 ++++++
 8 files changed, 59 insertions(+)
 create mode 100644 test/validator/samples/binding-await-catch/errors.json
 create mode 100644 test/validator/samples/binding-await-catch/input.svelte
 create mode 100644 test/validator/samples/binding-await-then-2/errors.json
 create mode 100644 test/validator/samples/binding-await-then-2/input.svelte
 create mode 100644 test/validator/samples/binding-await-then/errors.json
 create mode 100644 test/validator/samples/binding-await-then/input.svelte

diff --git a/src/compiler/compile/nodes/Binding.ts b/src/compiler/compile/nodes/Binding.ts
index 28e6af5aa1..7d6fad0a81 100644
--- a/src/compiler/compile/nodes/Binding.ts
+++ b/src/compiler/compile/nodes/Binding.ts
@@ -50,6 +50,13 @@ export default class Binding extends Node {
 				message: 'Cannot bind to a variable declared with the let: directive'
 			});
 		} else if (this.is_contextual) {
+			if (scope.is_await(name)) {
+				component.error(this, {
+					code: 'invalid-binding',
+					message: 'Cannot bind to a variable declared with {#await ... then} or {:catch} blocks'
+				});
+			}
+
 			scope.dependencies_for_name.get(name).forEach(name => {
 				const variable = component.var_lookup.get(name);
 				if (variable) {
diff --git a/src/compiler/compile/nodes/shared/TemplateScope.ts b/src/compiler/compile/nodes/shared/TemplateScope.ts
index 5f30d0c883..4e087eedf5 100644
--- a/src/compiler/compile/nodes/shared/TemplateScope.ts
+++ b/src/compiler/compile/nodes/shared/TemplateScope.ts
@@ -42,4 +42,9 @@ export default class TemplateScope {
 		const owner = this.get_owner(name);
 		return owner && (owner.type === 'Element' || owner.type === 'InlineComponent');
 	}
+
+	is_await(name: string) {
+		const owner = this.get_owner(name);
+		return owner && (owner.type === 'ThenBlock' || owner.type === 'CatchBlock');
+	}
 }
diff --git a/test/validator/samples/binding-await-catch/errors.json b/test/validator/samples/binding-await-catch/errors.json
new file mode 100644
index 0000000000..00141686f3
--- /dev/null
+++ b/test/validator/samples/binding-await-catch/errors.json
@@ -0,0 +1,9 @@
+[
+	{
+		"code": "invalid-binding",
+		"message": "Cannot bind to a variable declared with {#await ... then} or {:catch} blocks",
+		"pos": 79,
+		"start": { "line": 6, "column": 9, "character": 79 },
+		"end": { "line": 6, "column": 27, "character": 97 }
+	}
+]
diff --git a/test/validator/samples/binding-await-catch/input.svelte b/test/validator/samples/binding-await-catch/input.svelte
new file mode 100644
index 0000000000..b640f6305b
--- /dev/null
+++ b/test/validator/samples/binding-await-catch/input.svelte
@@ -0,0 +1,7 @@
+<script>
+  let promise = 0;
+</script>
+{#await promise}
+{:catch error}
+  <input bind:value={error} />
+{/await}
diff --git a/test/validator/samples/binding-await-then-2/errors.json b/test/validator/samples/binding-await-then-2/errors.json
new file mode 100644
index 0000000000..e734ed4717
--- /dev/null
+++ b/test/validator/samples/binding-await-then-2/errors.json
@@ -0,0 +1,9 @@
+[
+	{
+		"code": "invalid-binding",
+		"message": "Cannot bind to a variable declared with {#await ... then} or {:catch} blocks",
+		"pos": 78,
+		"start": { "line": 6, "column": 9, "character": 78 },
+		"end": { "line": 6, "column": 19, "character": 88 }
+	}
+]
diff --git a/test/validator/samples/binding-await-then-2/input.svelte b/test/validator/samples/binding-await-then-2/input.svelte
new file mode 100644
index 0000000000..e8c56c8e0b
--- /dev/null
+++ b/test/validator/samples/binding-await-then-2/input.svelte
@@ -0,0 +1,7 @@
+<script>
+  let promise = 0;
+</script>
+{#await promise}
+{:then value}
+  <input bind:value />
+{/await}
diff --git a/test/validator/samples/binding-await-then/errors.json b/test/validator/samples/binding-await-then/errors.json
new file mode 100644
index 0000000000..a611e7731f
--- /dev/null
+++ b/test/validator/samples/binding-await-then/errors.json
@@ -0,0 +1,9 @@
+[
+	{
+		"code": "invalid-binding",
+		"message": "Cannot bind to a variable declared with {#await ... then} or {:catch} blocks",
+		"pos": 75,
+		"start": { "line": 5, "column": 9, "character": 75 },
+		"end": { "line": 5, "column": 19, "character": 85 }
+	}
+]
diff --git a/test/validator/samples/binding-await-then/input.svelte b/test/validator/samples/binding-await-then/input.svelte
new file mode 100644
index 0000000000..bc55ef97e4
--- /dev/null
+++ b/test/validator/samples/binding-await-then/input.svelte
@@ -0,0 +1,6 @@
+<script>
+  let promise = 0;
+</script>
+{#await promise then value}
+  <input bind:value />
+{/await}

From bda254e250e737a1dd7acf6c732d656ce52034a1 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Thu, 16 Jan 2020 22:17:25 -0500
Subject: [PATCH 15/82] update changelog

---
 CHANGELOG.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index f833dfae2a..bc6cf36109 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+* Disallow two-way binding to a variable declared by an `{#await}` block ([#4012](https://github.com/sveltejs/svelte/issues/4012))
 * Allow access to `let:` variables in sibling attributes on slot root ([#4173](https://github.com/sveltejs/svelte/issues/4173))
 * Add some more known globals ([#4276](https://github.com/sveltejs/svelte/pull/4276))
 

From b39282a9188027903fdb99cdf762b640f11c6cc1 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Fri, 17 Jan 2020 07:22:40 -0500
Subject: [PATCH 16/82] apply event modifiers to <svelte:body> events (#4279)

---
 CHANGELOG.md                                  |  1 +
 .../compile/render_dom/wrappers/Body.ts       | 25 ++++++++-----------
 .../wrappers/Element/EventHandler.ts          |  3 ++-
 .../wrappers/shared/add_event_handlers.ts     |  5 ++--
 .../_config.js                                | 11 ++++++++
 .../main.svelte                               |  5 ++++
 6 files changed, 33 insertions(+), 17 deletions(-)
 create mode 100644 test/runtime/samples/event-handler-modifier-body-once/_config.js
 create mode 100644 test/runtime/samples/event-handler-modifier-body-once/main.svelte

diff --git a/CHANGELOG.md b/CHANGELOG.md
index bc6cf36109..9b2c8f5b07 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@
 * Disallow two-way binding to a variable declared by an `{#await}` block ([#4012](https://github.com/sveltejs/svelte/issues/4012))
 * Allow access to `let:` variables in sibling attributes on slot root ([#4173](https://github.com/sveltejs/svelte/issues/4173))
 * Add some more known globals ([#4276](https://github.com/sveltejs/svelte/pull/4276))
+* Correctly apply event modifiers to `<svelte:body>` events ([#4278](https://github.com/sveltejs/svelte/issues/4278))
 
 ## 3.17.1
 
diff --git a/src/compiler/compile/render_dom/wrappers/Body.ts b/src/compiler/compile/render_dom/wrappers/Body.ts
index e16ebc25bd..d80ef6c4a0 100644
--- a/src/compiler/compile/render_dom/wrappers/Body.ts
+++ b/src/compiler/compile/render_dom/wrappers/Body.ts
@@ -1,26 +1,23 @@
 import Block from '../Block';
 import Wrapper from './shared/Wrapper';
-import { b } from 'code-red';
+import { x } from 'code-red';
 import Body from '../../nodes/Body';
 import { Identifier } from 'estree';
 import EventHandler from './Element/EventHandler';
+import add_event_handlers from './shared/add_event_handlers';
+import { TemplateNode } from '../../../interfaces';
+import Renderer from '../Renderer';
 
 export default class BodyWrapper extends Wrapper {
 	node: Body;
+	handlers: EventHandler[];
 
-	render(block: Block, _parent_node: Identifier, _parent_nodes: Identifier) {
-		this.node.handlers
-			.map(handler => new EventHandler(handler, this))
-			.forEach(handler => {
-				const snippet = handler.get_snippet(block);
-
-				block.chunks.init.push(b`
-					@_document.body.addEventListener("${handler.node.name}", ${snippet});
-				`);
+	constructor(renderer: Renderer, block: Block, parent: Wrapper, node: TemplateNode) {
+		super(renderer, block, parent, node);
+		this.handlers = this.node.handlers.map(handler => new EventHandler(handler, this));
+	}
 
-				block.chunks.destroy.push(b`
-					@_document.body.removeEventListener("${handler.node.name}", ${snippet});
-				`);
-			});
+	render(block: Block, _parent_node: Identifier, _parent_nodes: Identifier) {
+		add_event_handlers(block, x`@_document.body`, this.handlers);
 	}
 }
diff --git a/src/compiler/compile/render_dom/wrappers/Element/EventHandler.ts b/src/compiler/compile/render_dom/wrappers/Element/EventHandler.ts
index 03183ee576..157e186ea6 100644
--- a/src/compiler/compile/render_dom/wrappers/Element/EventHandler.ts
+++ b/src/compiler/compile/render_dom/wrappers/Element/EventHandler.ts
@@ -2,6 +2,7 @@ import EventHandler from '../../../nodes/EventHandler';
 import Wrapper from '../shared/Wrapper';
 import Block from '../../Block';
 import { b, x, p } from 'code-red';
+import { Expression } from 'estree';
 
 const TRUE = x`true`;
 const FALSE = x`false`;
@@ -35,7 +36,7 @@ export default class EventHandlerWrapper {
 		return snippet;
 	}
 
-	render(block: Block, target: string) {
+	render(block: Block, target: string | Expression) {
 		let snippet = this.get_snippet(block);
 
 		if (this.node.modifiers.has('preventDefault')) snippet = x`@prevent_default(${snippet})`;
diff --git a/src/compiler/compile/render_dom/wrappers/shared/add_event_handlers.ts b/src/compiler/compile/render_dom/wrappers/shared/add_event_handlers.ts
index 23a37715cc..99b8080b17 100644
--- a/src/compiler/compile/render_dom/wrappers/shared/add_event_handlers.ts
+++ b/src/compiler/compile/render_dom/wrappers/shared/add_event_handlers.ts
@@ -1,9 +1,10 @@
 import Block from '../../Block';
 import EventHandler from '../Element/EventHandler';
+import { Expression } from 'estree';
 
 export default function add_event_handlers(
 	block: Block,
-	target: string,
+	target: string | Expression,
 	handlers: EventHandler[]
 ) {
 	handlers.forEach(handler => add_event_handler(block, target, handler));
@@ -11,7 +12,7 @@ export default function add_event_handlers(
 
 export function add_event_handler(
 	block: Block,
-	target: string,
+	target: string | Expression,
 	handler: EventHandler
 ) {
 	handler.render(block, target);
diff --git a/test/runtime/samples/event-handler-modifier-body-once/_config.js b/test/runtime/samples/event-handler-modifier-body-once/_config.js
new file mode 100644
index 0000000000..4127034010
--- /dev/null
+++ b/test/runtime/samples/event-handler-modifier-body-once/_config.js
@@ -0,0 +1,11 @@
+export default {
+	async test({ assert, component, window }) {
+		const event = new window.MouseEvent('click');
+
+		await window.document.body.dispatchEvent(event);
+		assert.equal(component.count, 1);
+
+		await window.document.body.dispatchEvent(event);
+		assert.equal(component.count, 1);
+	}
+};
diff --git a/test/runtime/samples/event-handler-modifier-body-once/main.svelte b/test/runtime/samples/event-handler-modifier-body-once/main.svelte
new file mode 100644
index 0000000000..423a75d1f0
--- /dev/null
+++ b/test/runtime/samples/event-handler-modifier-body-once/main.svelte
@@ -0,0 +1,5 @@
+<script>
+	export let count = 0;
+</script>
+
+<svelte:body on:click|once="{() => count += 1}"/>
\ No newline at end of file

From 2f81365e44f585c28295cb3937910eef00a35b0e Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Sat, 18 Jan 2020 07:10:13 -0500
Subject: [PATCH 17/82] fix awaited expressions that need parentheses (#4283)

---
 CHANGELOG.md                                              | 1 +
 package-lock.json                                         | 8 ++++----
 package.json                                              | 2 +-
 test/js/samples/debug-empty/expected.js                   | 2 +-
 test/js/samples/debug-foo-bar-baz-things/expected.js      | 2 +-
 test/js/samples/debug-foo/expected.js                     | 2 +-
 .../samples/dev-warning-missing-data-computed/expected.js | 2 +-
 7 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9b2c8f5b07..5264f35504 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@
 
 * Disallow two-way binding to a variable declared by an `{#await}` block ([#4012](https://github.com/sveltejs/svelte/issues/4012))
 * Allow access to `let:` variables in sibling attributes on slot root ([#4173](https://github.com/sveltejs/svelte/issues/4173))
+* Fix code generation for `await`ed expressions that need parentheses ([#4267](https://github.com/sveltejs/svelte/issues/4267))
 * Add some more known globals ([#4276](https://github.com/sveltejs/svelte/pull/4276))
 * Correctly apply event modifiers to `<svelte:body>` events ([#4278](https://github.com/sveltejs/svelte/issues/4278))
 
diff --git a/package-lock.json b/package-lock.json
index 9ee0b53af6..4d902d5c48 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "svelte",
-  "version": "3.17.0",
+  "version": "3.17.1",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
@@ -597,9 +597,9 @@
       "dev": true
     },
     "code-red": {
-      "version": "0.0.28",
-      "resolved": "https://registry.npmjs.org/code-red/-/code-red-0.0.28.tgz",
-      "integrity": "sha512-k9L7Sp85HNt3f/CvfrZKXoZOaO0tWOJCw2kU5GKc/c5pDj52OgBa0J+krMRmYtnGzS2dk4Xrn0EjjsJaM51hWQ==",
+      "version": "0.0.30",
+      "resolved": "https://registry.npmjs.org/code-red/-/code-red-0.0.30.tgz",
+      "integrity": "sha512-nsScy3A59tbV5uzndcedIEGHmdWNEByJrC7DUyb0Wh7qZcoPfAlcYsr0ZINkAEhZofSI26F1mi+lRO0/6EV2/g==",
       "dev": true,
       "requires": {
         "acorn": "^7.1.0",
diff --git a/package.json b/package.json
index c7ac32f3ae..671a7e5025 100644
--- a/package.json
+++ b/package.json
@@ -70,7 +70,7 @@
     "acorn": "^7.1.0",
     "agadoo": "^1.1.0",
     "c8": "^5.0.1",
-    "code-red": "0.0.28",
+    "code-red": "0.0.30",
     "codecov": "^3.5.0",
     "css-tree": "1.0.0-alpha22",
     "eslint": "^6.3.0",
diff --git a/test/js/samples/debug-empty/expected.js b/test/js/samples/debug-empty/expected.js
index 5821faadf1..358363c661 100644
--- a/test/js/samples/debug-empty/expected.js
+++ b/test/js/samples/debug-empty/expected.js
@@ -103,7 +103,7 @@ class Component extends SvelteComponentDev {
 		});
 
 		const { ctx } = this.$$;
-		const props = options.props || ({});
+		const props = options.props || {};
 
 		if (/*name*/ ctx[0] === undefined && !("name" in props)) {
 			console.warn("<Component> was created without expected prop 'name'");
diff --git a/test/js/samples/debug-foo-bar-baz-things/expected.js b/test/js/samples/debug-foo-bar-baz-things/expected.js
index a1d6dba3b3..fc65c59eda 100644
--- a/test/js/samples/debug-foo-bar-baz-things/expected.js
+++ b/test/js/samples/debug-foo-bar-baz-things/expected.js
@@ -210,7 +210,7 @@ class Component extends SvelteComponentDev {
 		});
 
 		const { ctx } = this.$$;
-		const props = options.props || ({});
+		const props = options.props || {};
 
 		if (/*things*/ ctx[0] === undefined && !("things" in props)) {
 			console.warn("<Component> was created without expected prop 'things'");
diff --git a/test/js/samples/debug-foo/expected.js b/test/js/samples/debug-foo/expected.js
index af79667cc2..710d6b2232 100644
--- a/test/js/samples/debug-foo/expected.js
+++ b/test/js/samples/debug-foo/expected.js
@@ -198,7 +198,7 @@ class Component extends SvelteComponentDev {
 		});
 
 		const { ctx } = this.$$;
-		const props = options.props || ({});
+		const props = options.props || {};
 
 		if (/*things*/ ctx[0] === undefined && !("things" in props)) {
 			console.warn("<Component> was created without expected prop 'things'");
diff --git a/test/js/samples/dev-warning-missing-data-computed/expected.js b/test/js/samples/dev-warning-missing-data-computed/expected.js
index beb794a50c..cc16de67e6 100644
--- a/test/js/samples/dev-warning-missing-data-computed/expected.js
+++ b/test/js/samples/dev-warning-missing-data-computed/expected.js
@@ -107,7 +107,7 @@ class Component extends SvelteComponentDev {
 		});
 
 		const { ctx } = this.$$;
-		const props = options.props || ({});
+		const props = options.props || {};
 
 		if (/*foo*/ ctx[0] === undefined && !("foo" in props)) {
 			console.warn("<Component> was created without expected prop 'foo'");

From e4460e38ba58d5209514f0fa93dc61b6bb1ebb54 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Sun, 19 Jan 2020 13:36:22 -0500
Subject: [PATCH 18/82] fix '~=' and class selectors with arbitrary whitespace
 (#4286)

---
 CHANGELOG.md                                        |  1 +
 src/compiler/compile/css/Selector.ts                |  6 +++---
 .../expected.css                                    |  1 +
 .../input.svelte                                    | 13 +++++++++++++
 4 files changed, 18 insertions(+), 3 deletions(-)
 create mode 100644 test/css/samples/attribute-selector-word-arbitrary-whitespace/expected.css
 create mode 100644 test/css/samples/attribute-selector-word-arbitrary-whitespace/input.svelte

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5264f35504..5b0bb4751d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@
 
 * Disallow two-way binding to a variable declared by an `{#await}` block ([#4012](https://github.com/sveltejs/svelte/issues/4012))
 * Allow access to `let:` variables in sibling attributes on slot root ([#4173](https://github.com/sveltejs/svelte/issues/4173))
+* Fix `~=` and class selector matching against values separated by any whitespace characters ([#4242](https://github.com/sveltejs/svelte/issues/4242))
 * Fix code generation for `await`ed expressions that need parentheses ([#4267](https://github.com/sveltejs/svelte/issues/4267))
 * Add some more known globals ([#4276](https://github.com/sveltejs/svelte/pull/4276))
 * Correctly apply event modifiers to `<svelte:body>` events ([#4278](https://github.com/sveltejs/svelte/issues/4278))
diff --git a/src/compiler/compile/css/Selector.ts b/src/compiler/compile/css/Selector.ts
index eecb0cd975..39bbc2e8d1 100644
--- a/src/compiler/compile/css/Selector.ts
+++ b/src/compiler/compile/css/Selector.ts
@@ -171,7 +171,7 @@ function apply_selector(blocks: Block[], node: Element, stack: Element[], to_enc
 				if (ancestor_block.global) {
 					continue;
 				}
-				
+
 				for (const stack_node of stack) {
 					if (block_might_apply_to_node(ancestor_block, stack_node) !== BlockAppliesToNode.NotPossible) {
 						to_encapsulate.push({ node: stack_node, block: ancestor_block });
@@ -256,7 +256,7 @@ function test_attribute(operator, expected_value, case_insensitive, value) {
 	}
 	switch (operator) {
 		case '=': return value === expected_value;
-		case '~=': return ` ${value} `.includes(` ${expected_value} `);
+		case '~=': return value.split(/\s/).includes(expected_value);
 		case '|=': return `${value}-`.startsWith(`${expected_value}-`);
 		case '^=': return value.startsWith(expected_value);
 		case '$=': return value.endsWith(expected_value);
@@ -295,7 +295,7 @@ function attribute_matches(node: CssNode, name: string, expected_value: string,
 
 		// impossible to find out all combinations
 		if (current_possible_values.has(UNKNOWN)) return true;
-		
+
 		if (prev_values.length > 0) {
 			const start_with_space = [];
 			const remaining = [];
diff --git a/test/css/samples/attribute-selector-word-arbitrary-whitespace/expected.css b/test/css/samples/attribute-selector-word-arbitrary-whitespace/expected.css
new file mode 100644
index 0000000000..c1c0f3fdf6
--- /dev/null
+++ b/test/css/samples/attribute-selector-word-arbitrary-whitespace/expected.css
@@ -0,0 +1 @@
+.foo.svelte-xyz{color:red}[class~="bar"].svelte-xyz{background:blue}
\ No newline at end of file
diff --git a/test/css/samples/attribute-selector-word-arbitrary-whitespace/input.svelte b/test/css/samples/attribute-selector-word-arbitrary-whitespace/input.svelte
new file mode 100644
index 0000000000..758aa27e0b
--- /dev/null
+++ b/test/css/samples/attribute-selector-word-arbitrary-whitespace/input.svelte
@@ -0,0 +1,13 @@
+<div class="
+foo
+bar
+"></div>
+
+<style>
+	.foo {
+		color: red;
+	}
+	[class~="bar"] {
+		background: blue;
+	}
+</style>

From 33c3a02ee4b9ac3ee9d9dbec1c7328db0d49d6c0 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Mon, 20 Jan 2020 10:31:31 -0500
Subject: [PATCH 19/82] failing test

---
 test/hydration/samples/element-attribute-removed/_before.html | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/hydration/samples/element-attribute-removed/_before.html b/test/hydration/samples/element-attribute-removed/_before.html
index c6a8a8c95d..80c0591a4d 100644
--- a/test/hydration/samples/element-attribute-removed/_before.html
+++ b/test/hydration/samples/element-attribute-removed/_before.html
@@ -1 +1 @@
-<div class='foo'></div>
\ No newline at end of file
+<div class='foo' title='bar'></div>
\ No newline at end of file

From 91e0d1b720e209833f11e894b956ea361ef8878a Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Mon, 20 Jan 2020 10:34:29 -0500
Subject: [PATCH 20/82] fix removing attributes during hydration (#1733)

---
 src/runtime/internal/dom.ts | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/src/runtime/internal/dom.ts b/src/runtime/internal/dom.ts
index f9e89f41b9..5a165136ce 100644
--- a/src/runtime/internal/dom.ts
+++ b/src/runtime/internal/dom.ts
@@ -152,11 +152,16 @@ export function claim_element(nodes, name, attributes, svg) {
 	for (let i = 0; i < nodes.length; i += 1) {
 		const node = nodes[i];
 		if (node.nodeName === name) {
-			for (let j = 0; j < node.attributes.length; j += 1) {
+			let j = 0;
+			while (j < node.attributes.length) {
 				const attribute = node.attributes[j];
-				if (!attributes[attribute.name]) node.removeAttribute(attribute.name);
+				if (attributes[attribute.name]) {
+					j++;
+				} else {
+					node.removeAttribute(attribute.name);
+				}
 			}
-			return nodes.splice(i, 1)[0]; // TODO strip unwanted attributes
+			return nodes.splice(i, 1)[0];
 		}
 	}
 

From b0415a269bb4918048508b97399f97a71f6499fe Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Mon, 20 Jan 2020 10:35:13 -0500
Subject: [PATCH 21/82] update changelog

---
 CHANGELOG.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5b0bb4751d..d9ec5900b4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+* Fix removing attributes during hydration ([#1733](https://github.com/sveltejs/svelte/issues/1733))
 * Disallow two-way binding to a variable declared by an `{#await}` block ([#4012](https://github.com/sveltejs/svelte/issues/4012))
 * Allow access to `let:` variables in sibling attributes on slot root ([#4173](https://github.com/sveltejs/svelte/issues/4173))
 * Fix `~=` and class selector matching against values separated by any whitespace characters ([#4242](https://github.com/sveltejs/svelte/issues/4242))

From f12340acf02e6c8e7dc23cafe0469eb72d278fc8 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Mon, 20 Jan 2020 21:17:24 -0500
Subject: [PATCH 22/82] preserve js comments where possible (#4293)

---
 CHANGELOG.md                                           |  1 +
 package-lock.json                                      |  6 +++---
 package.json                                           |  2 +-
 src/compiler/parse/acorn.ts                            |  9 ++++-----
 .../js/samples/action-custom-event-handler/expected.js |  2 +-
 .../samples/collapses-text-around-comments/expected.js |  2 +-
 test/js/samples/css-media-query/expected.js            |  2 +-
 test/js/samples/event-modifiers/expected.js            |  4 ++--
 test/js/samples/ssr-no-oncreate-etc/expected.js        |  2 +-
 test/parser/samples/script-comment-only/output.json    | 10 +++++++++-
 .../script-comment-trailing-multiline/output.json      | 10 +++++++++-
 .../parser/samples/script-comment-trailing/output.json | 10 +++++++++-
 12 files changed, 42 insertions(+), 18 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index d9ec5900b4..59fa25682e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@
 * Allow access to `let:` variables in sibling attributes on slot root ([#4173](https://github.com/sveltejs/svelte/issues/4173))
 * Fix `~=` and class selector matching against values separated by any whitespace characters ([#4242](https://github.com/sveltejs/svelte/issues/4242))
 * Fix code generation for `await`ed expressions that need parentheses ([#4267](https://github.com/sveltejs/svelte/issues/4267))
+* Preserve JavaScript comments from the original component source where possible ([#4268](https://github.com/sveltejs/svelte/issues/4268))
 * Add some more known globals ([#4276](https://github.com/sveltejs/svelte/pull/4276))
 * Correctly apply event modifiers to `<svelte:body>` events ([#4278](https://github.com/sveltejs/svelte/issues/4278))
 
diff --git a/package-lock.json b/package-lock.json
index 4d902d5c48..90f5a331ed 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -597,9 +597,9 @@
       "dev": true
     },
     "code-red": {
-      "version": "0.0.30",
-      "resolved": "https://registry.npmjs.org/code-red/-/code-red-0.0.30.tgz",
-      "integrity": "sha512-nsScy3A59tbV5uzndcedIEGHmdWNEByJrC7DUyb0Wh7qZcoPfAlcYsr0ZINkAEhZofSI26F1mi+lRO0/6EV2/g==",
+      "version": "0.0.31",
+      "resolved": "https://registry.npmjs.org/code-red/-/code-red-0.0.31.tgz",
+      "integrity": "sha512-7Gf3vm8pDbs+H/hKsaqOZe0xKlE9Neah12GCfs7qun3fBUaOXwexAMjn0Eo9cvJJvhRMaL0jgPiY9ZGLTWoe8A==",
       "dev": true,
       "requires": {
         "acorn": "^7.1.0",
diff --git a/package.json b/package.json
index 671a7e5025..6a66276c2d 100644
--- a/package.json
+++ b/package.json
@@ -70,7 +70,7 @@
     "acorn": "^7.1.0",
     "agadoo": "^1.1.0",
     "c8": "^5.0.1",
-    "code-red": "0.0.30",
+    "code-red": "0.0.31",
     "codecov": "^3.5.0",
     "css-tree": "1.0.0-alpha22",
     "eslint": "^6.3.0",
diff --git a/src/compiler/parse/acorn.ts b/src/compiler/parse/acorn.ts
index 30ab3c398c..d14721cdab 100644
--- a/src/compiler/parse/acorn.ts
+++ b/src/compiler/parse/acorn.ts
@@ -1,14 +1,13 @@
-import * as acorn from 'acorn';
+import { Node } from 'acorn';
+import * as code_red from 'code-red';
 
-const Parser = acorn.Parser;
-
-export const parse = (source: string) => Parser.parse(source, {
+export const parse = (source: string): Node => code_red.parse(source, {
 	sourceType: 'module',
 	ecmaVersion: 11,
 	locations: true
 });
 
-export const parse_expression_at = (source: string, index: number) => Parser.parseExpressionAt(source, index, {
+export const parse_expression_at = (source: string, index: number): Node => code_red.parseExpressionAt(source, index, {
 	ecmaVersion: 11,
 	locations: true
 });
\ No newline at end of file
diff --git a/test/js/samples/action-custom-event-handler/expected.js b/test/js/samples/action-custom-event-handler/expected.js
index 968b5965d5..ead6d90e06 100644
--- a/test/js/samples/action-custom-event-handler/expected.js
+++ b/test/js/samples/action-custom-event-handler/expected.js
@@ -43,7 +43,7 @@ function handleFoo(bar) {
 
 function foo(node, callback) {
 	
-}
+} // code goes here
 
 function instance($$self, $$props, $$invalidate) {
 	let { bar } = $$props;
diff --git a/test/js/samples/collapses-text-around-comments/expected.js b/test/js/samples/collapses-text-around-comments/expected.js
index 8c0e9d5373..6fef0f9490 100644
--- a/test/js/samples/collapses-text-around-comments/expected.js
+++ b/test/js/samples/collapses-text-around-comments/expected.js
@@ -63,4 +63,4 @@ class Component extends SvelteComponent {
 	}
 }
 
-export default Component;
+export default Component;
\ No newline at end of file
diff --git a/test/js/samples/css-media-query/expected.js b/test/js/samples/css-media-query/expected.js
index 0566c22ddd..f477670059 100644
--- a/test/js/samples/css-media-query/expected.js
+++ b/test/js/samples/css-media-query/expected.js
@@ -46,4 +46,4 @@ class Component extends SvelteComponent {
 	}
 }
 
-export default Component;
+export default Component;
\ No newline at end of file
diff --git a/test/js/samples/event-modifiers/expected.js b/test/js/samples/event-modifiers/expected.js
index 252034a431..c12c3523a0 100644
--- a/test/js/samples/event-modifiers/expected.js
+++ b/test/js/samples/event-modifiers/expected.js
@@ -63,11 +63,11 @@ function create_fragment(ctx) {
 
 function handleTouchstart() {
 	
-}
+} // ...
 
 function handleClick() {
 	
-}
+} // ...
 
 class Component extends SvelteComponent {
 	constructor(options) {
diff --git a/test/js/samples/ssr-no-oncreate-etc/expected.js b/test/js/samples/ssr-no-oncreate-etc/expected.js
index 276587eeca..803f06a882 100644
--- a/test/js/samples/ssr-no-oncreate-etc/expected.js
+++ b/test/js/samples/ssr-no-oncreate-etc/expected.js
@@ -13,7 +13,7 @@ function foo() {
 
 function swipe(node, callback) {
 	
-}
+} // TODO implement
 
 const Component = create_ssr_component(($$result, $$props, $$bindings, $$slots) => {
 	onMount(() => {
diff --git a/test/parser/samples/script-comment-only/output.json b/test/parser/samples/script-comment-only/output.json
index 3441d8a7bb..e090b30ae6 100644
--- a/test/parser/samples/script-comment-only/output.json
+++ b/test/parser/samples/script-comment-only/output.json
@@ -41,7 +41,15 @@
 				}
 			},
 			"body": [],
-			"sourceType": "module"
+			"sourceType": "module",
+			"trailingComments": [
+				{
+					"type": "Line",
+					"value": " TODO write some code",
+					"start": 10,
+					"end": 33
+				}
+			]
 		}
 	}
 }
\ No newline at end of file
diff --git a/test/parser/samples/script-comment-trailing-multiline/output.json b/test/parser/samples/script-comment-trailing-multiline/output.json
index 3c02b1fbde..be83eeea8b 100644
--- a/test/parser/samples/script-comment-trailing-multiline/output.json
+++ b/test/parser/samples/script-comment-trailing-multiline/output.json
@@ -134,7 +134,15 @@
 					"kind": "let"
 				}
 			],
-			"sourceType": "module"
+			"sourceType": "module",
+			"trailingComments": [
+				{
+					"type": "Block",
+					"value": "\n\ttrailing multiline comment\n",
+					"start": 32,
+					"end": 67
+				}
+			]
 		}
 	}
 }
\ No newline at end of file
diff --git a/test/parser/samples/script-comment-trailing/output.json b/test/parser/samples/script-comment-trailing/output.json
index beca001042..a2bc00bc00 100644
--- a/test/parser/samples/script-comment-trailing/output.json
+++ b/test/parser/samples/script-comment-trailing/output.json
@@ -134,7 +134,15 @@
 					"kind": "let"
 				}
 			],
-			"sourceType": "module"
+			"sourceType": "module",
+			"trailingComments": [
+				{
+					"type": "Line",
+					"value": " trailing line comment",
+					"start": 32,
+					"end": 56
+				}
+			]
 		}
 	}
 }
\ No newline at end of file

From e93c9913623ba43d8424191fe33f8bebb36e7dea Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Mon, 20 Jan 2020 21:18:15 -0500
Subject: [PATCH 23/82] -> v3.17.2

---
 CHANGELOG.md      | 2 +-
 package-lock.json | 2 +-
 package.json      | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 59fa25682e..92e61719d0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,6 @@
 # Svelte changelog
 
-## Unreleased
+## 3.17.2
 
 * Fix removing attributes during hydration ([#1733](https://github.com/sveltejs/svelte/issues/1733))
 * Disallow two-way binding to a variable declared by an `{#await}` block ([#4012](https://github.com/sveltejs/svelte/issues/4012))
diff --git a/package-lock.json b/package-lock.json
index 90f5a331ed..ca225baa1b 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "svelte",
-  "version": "3.17.1",
+  "version": "3.17.2",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
diff --git a/package.json b/package.json
index 6a66276c2d..0910dca8c0 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "svelte",
-  "version": "3.17.1",
+  "version": "3.17.2",
   "description": "Cybernetically enhanced web apps",
   "module": "index.mjs",
   "main": "index",

From e4daaccd06cfe8fe1f4885fcb10942132153b521 Mon Sep 17 00:00:00 2001
From: Tan Li Hau <tanhauhau@users.noreply.github.com>
Date: Wed, 22 Jan 2020 19:32:24 +0800
Subject: [PATCH 24/82] fix nested block not reactive (#4294)

---
 CHANGELOG.md                                  |  4 +++
 src/compiler/compile/render_dom/Block.ts      |  3 ++
 .../component-slot-nested-if/Display.svelte   |  2 ++
 .../component-slot-nested-if/Input.svelte     |  6 ++++
 .../component-slot-nested-if/_config.js       | 30 +++++++++++++++++++
 .../component-slot-nested-if/main.svelte      | 10 +++++++
 6 files changed, 55 insertions(+)
 create mode 100644 test/runtime/samples/component-slot-nested-if/Display.svelte
 create mode 100644 test/runtime/samples/component-slot-nested-if/Input.svelte
 create mode 100644 test/runtime/samples/component-slot-nested-if/_config.js
 create mode 100644 test/runtime/samples/component-slot-nested-if/main.svelte

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 92e61719d0..60153dcaba 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Svelte changelog
 
+## Unreleased
+
+* Fix updating a `<slot>` inside an `{#if}` or other block ([#4292](https://github.com/sveltejs/svelte/issues/4292))
+
 ## 3.17.2
 
 * Fix removing attributes during hydration ([#1733](https://github.com/sveltejs/svelte/issues/1733))
diff --git a/src/compiler/compile/render_dom/Block.ts b/src/compiler/compile/render_dom/Block.ts
index 68d28024fe..62bdc5bdd9 100644
--- a/src/compiler/compile/render_dom/Block.ts
+++ b/src/compiler/compile/render_dom/Block.ts
@@ -160,6 +160,9 @@ export default class Block {
 		});
 
 		this.has_update_method = true;
+		if (this.parent) {
+			this.parent.add_dependencies(dependencies);
+		}
 	}
 
 	add_element(
diff --git a/test/runtime/samples/component-slot-nested-if/Display.svelte b/test/runtime/samples/component-slot-nested-if/Display.svelte
new file mode 100644
index 0000000000..d9034e4be2
--- /dev/null
+++ b/test/runtime/samples/component-slot-nested-if/Display.svelte
@@ -0,0 +1,2 @@
+Display:
+<slot></slot>
\ No newline at end of file
diff --git a/test/runtime/samples/component-slot-nested-if/Input.svelte b/test/runtime/samples/component-slot-nested-if/Input.svelte
new file mode 100644
index 0000000000..fd8f22db00
--- /dev/null
+++ b/test/runtime/samples/component-slot-nested-if/Input.svelte
@@ -0,0 +1,6 @@
+<script>
+	let val;
+</script>
+
+<input bind:value={val} />
+<slot {val}></slot>
\ No newline at end of file
diff --git a/test/runtime/samples/component-slot-nested-if/_config.js b/test/runtime/samples/component-slot-nested-if/_config.js
new file mode 100644
index 0000000000..89dfd006cc
--- /dev/null
+++ b/test/runtime/samples/component-slot-nested-if/_config.js
@@ -0,0 +1,30 @@
+export default {
+	html: `
+    <input>
+	`,
+	async test({ assert, target, snapshot, component, window }) {
+		const input = target.querySelector('input');
+
+		input.value = 'a';
+		await input.dispatchEvent(new window.Event('input'));
+
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+			<input>
+			Display: a
+		`
+		);
+
+		input.value = 'abc';
+		await input.dispatchEvent(new window.Event('input'));
+
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+			<input>
+			Display: abc
+		`
+		);
+	},
+};
diff --git a/test/runtime/samples/component-slot-nested-if/main.svelte b/test/runtime/samples/component-slot-nested-if/main.svelte
new file mode 100644
index 0000000000..727927b157
--- /dev/null
+++ b/test/runtime/samples/component-slot-nested-if/main.svelte
@@ -0,0 +1,10 @@
+<script>
+	import Input from "./Input.svelte";
+	import Display from "./Display.svelte";
+</script>
+
+<Input let:val={foo}>
+	{#if foo}
+		<Display>{foo}</Display>
+	{/if}
+</Input>

From 5107ad38b6ce0e388cb2eb99361c5000c4b6de91 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Wed, 22 Jan 2020 09:19:32 -0500
Subject: [PATCH 25/82] fix deriving from RxJS observables (#4300)

---
 CHANGELOG.md                  |  1 +
 src/runtime/internal/utils.ts |  4 ++--
 src/runtime/store/index.ts    |  5 +++--
 test/store/index.js           | 25 +++++++++++++++----------
 4 files changed, 21 insertions(+), 14 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 60153dcaba..388fe61397 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@
 ## Unreleased
 
 * Fix updating a `<slot>` inside an `{#if}` or other block ([#4292](https://github.com/sveltejs/svelte/issues/4292))
+* Fix using RxJS observables in `derived` stores ([#4298](https://github.com/sveltejs/svelte/issues/4298))
 
 ## 3.17.2
 
diff --git a/src/runtime/internal/utils.ts b/src/runtime/internal/utils.ts
index c94a135869..c7722e1a07 100644
--- a/src/runtime/internal/utils.ts
+++ b/src/runtime/internal/utils.ts
@@ -48,8 +48,8 @@ export function validate_store(store, name) {
 	}
 }
 
-export function subscribe(store, callback) {
-	const unsub = store.subscribe(callback);
+export function subscribe(store, ...callbacks) {
+	const unsub = store.subscribe(...callbacks);
 	return unsub.unsubscribe ? () => unsub.unsubscribe() : unsub;
 }
 
diff --git a/src/runtime/store/index.ts b/src/runtime/store/index.ts
index 64a63d4179..2bbfdfcd60 100644
--- a/src/runtime/store/index.ts
+++ b/src/runtime/store/index.ts
@@ -1,4 +1,4 @@
-import { run_all, noop, safe_not_equal, is_function, get_store_value } from 'svelte/internal';
+import { run_all, subscribe, noop, safe_not_equal, is_function, get_store_value } from 'svelte/internal';
 
 /** Callback to inform of a value updates. */
 type Subscriber<T> = (value: T) => void;
@@ -173,7 +173,8 @@ export function derived<T>(stores: Stores, fn: Function, initial_value?: T): Rea
 			}
 		};
 
-		const unsubscribers = stores_array.map((store, i) => store.subscribe(
+		const unsubscribers = stores_array.map((store, i) => subscribe(
+			store,
 			(value) => {
 				values[i] = value;
 				pending &= ~(1 << i);
diff --git a/test/store/index.js b/test/store/index.js
index a39fab86e6..2af4a6f35d 100644
--- a/test/store/index.js
+++ b/test/store/index.js
@@ -116,6 +116,15 @@ describe('store', () => {
 		});
 	});
 
+	const fake_observable = {
+		subscribe(fn) {
+			fn(42);
+			return {
+				unsubscribe: () => {}
+			};
+		}
+	};
+
 	describe('derived', () => {
 		it('maps a single store', () => {
 			const a = writable(1);
@@ -346,6 +355,11 @@ describe('store', () => {
 			b.set(2);
 			assert.deepEqual(get(c), 'two 2');
 		});
+
+		it('works with RxJS-style observables', () => {
+			const d = derived(fake_observable, _ => _);
+			assert.equal(get(d), 42);
+		});
 	});
 
 	describe('get', () => {
@@ -355,16 +369,7 @@ describe('store', () => {
 		});
 
 		it('works with RxJS-style observables', () => {
-			const observable = {
-				subscribe(fn) {
-					fn(42);
-					return {
-						unsubscribe: () => {}
-					};
-				}
-			};
-
-			assert.equal(get(observable), 42);
+			assert.equal(get(fake_observable), 42);
 		});
 	});
 });

From 1a343b165c577429e968cea48607cccabf714b9b Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Wed, 22 Jan 2020 11:05:31 -0500
Subject: [PATCH 26/82] disallow duplicate each keys in dev mode (#4303)

---
 CHANGELOG.md                                       |  1 +
 .../compile/render_dom/wrappers/EachBlock.ts       |  2 ++
 src/runtime/internal/keyed_each.ts                 | 14 +++++++++-----
 .../samples/keyed-each-dev-unique/_config.js       |  7 +++++++
 .../samples/keyed-each-dev-unique/main.svelte      |  7 +++++++
 5 files changed, 26 insertions(+), 5 deletions(-)
 create mode 100644 test/runtime/samples/keyed-each-dev-unique/_config.js
 create mode 100644 test/runtime/samples/keyed-each-dev-unique/main.svelte

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 388fe61397..5838dcac80 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@
 
 * Fix updating a `<slot>` inside an `{#if}` or other block ([#4292](https://github.com/sveltejs/svelte/issues/4292))
 * Fix using RxJS observables in `derived` stores ([#4298](https://github.com/sveltejs/svelte/issues/4298))
+* Add dev mode check to disallow duplicate keys in a keyed `{#each}` ([#4301](https://github.com/sveltejs/svelte/issues/4301))
 
 ## 3.17.2
 
diff --git a/src/compiler/compile/render_dom/wrappers/EachBlock.ts b/src/compiler/compile/render_dom/wrappers/EachBlock.ts
index 4928b5a38c..639a8831bd 100644
--- a/src/compiler/compile/render_dom/wrappers/EachBlock.ts
+++ b/src/compiler/compile/render_dom/wrappers/EachBlock.ts
@@ -374,6 +374,7 @@ export default class EachBlockWrapper extends Wrapper {
 		block.chunks.init.push(b`
 			const ${get_key} = #ctx => ${this.node.key.manipulate(block)};
 
+			${this.renderer.options.dev && b`@validate_each_keys(#ctx, ${this.vars.each_block_value}, ${this.vars.get_each_context}, ${get_key});`}
 			for (let #i = 0; #i < ${data_length}; #i += 1) {
 				let child_ctx = ${this.vars.get_each_context}(#ctx, ${this.vars.each_block_value}, #i);
 				let key = ${get_key}(child_ctx);
@@ -416,6 +417,7 @@ export default class EachBlockWrapper extends Wrapper {
 
 			${this.block.has_outros && b`@group_outros();`}
 			${this.node.has_animation && b`for (let #i = 0; #i < ${view_length}; #i += 1) ${iterations}[#i].r();`}
+			${this.renderer.options.dev && b`@validate_each_keys(#ctx, ${this.vars.each_block_value}, ${this.vars.get_each_context}, ${get_key});`}
 			${iterations} = @update_keyed_each(${iterations}, #dirty, ${get_key}, ${dynamic ? 1 : 0}, #ctx, ${this.vars.each_block_value}, ${lookup}, ${update_mount_node}, ${destroy}, ${create_each_block}, ${update_anchor_node}, ${this.vars.get_each_context});
 			${this.node.has_animation && b`for (let #i = 0; #i < ${view_length}; #i += 1) ${iterations}[#i].a();`}
 			${this.block.has_outros && b`@check_outros();`}
diff --git a/src/runtime/internal/keyed_each.ts b/src/runtime/internal/keyed_each.ts
index 8382a2f76a..b397335c87 100644
--- a/src/runtime/internal/keyed_each.ts
+++ b/src/runtime/internal/keyed_each.ts
@@ -108,9 +108,13 @@ export function update_keyed_each(old_blocks, dirty, get_key, dynamic, ctx, list
 	return new_blocks;
 }
 
-export function measure(blocks) {
-	const rects = {};
-	let i = blocks.length;
-	while (i--) rects[blocks[i].key] = blocks[i].node.getBoundingClientRect();
-	return rects;
+export function validate_each_keys(ctx, list, get_context, get_key) {
+	const keys = new Set();
+	for (let i = 0; i < list.length; i++) {
+		const key = get_key(get_context(ctx, list, i));
+		if (keys.has(key)) {
+			throw new Error(`Cannot have duplicate keys in a keyed each`);
+		}
+		keys.add(key);
+	}
 }
diff --git a/test/runtime/samples/keyed-each-dev-unique/_config.js b/test/runtime/samples/keyed-each-dev-unique/_config.js
new file mode 100644
index 0000000000..8f46af9d52
--- /dev/null
+++ b/test/runtime/samples/keyed-each-dev-unique/_config.js
@@ -0,0 +1,7 @@
+export default {
+	compileOptions: {
+		dev: true
+	},
+
+	error: `Cannot have duplicate keys in a keyed each`
+};
diff --git a/test/runtime/samples/keyed-each-dev-unique/main.svelte b/test/runtime/samples/keyed-each-dev-unique/main.svelte
new file mode 100644
index 0000000000..870e7beaa1
--- /dev/null
+++ b/test/runtime/samples/keyed-each-dev-unique/main.svelte
@@ -0,0 +1,7 @@
+<script>
+	const array = [1, 2, 3, 1];
+</script>
+
+{#each array as item (item)}
+	{item}
+{/each}

From 3ba4f8abcad48b0380c9046d0f9230c1fc330964 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Wed, 22 Jan 2020 20:11:45 -0500
Subject: [PATCH 27/82] site: fix a couple absolute links

---
 site/content/blog/2019-04-20-write-less-code.md | 2 +-
 site/content/docs/01-component-format.md        | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/site/content/blog/2019-04-20-write-less-code.md b/site/content/blog/2019-04-20-write-less-code.md
index d6c8b77193..d56c5312e8 100644
--- a/site/content/blog/2019-04-20-write-less-code.md
+++ b/site/content/blog/2019-04-20-write-less-code.md
@@ -159,6 +159,6 @@ In Vue, meanwhile, we have a default export with a `data` function that returns
 
 ## Death to boilerplate
 
-These are just some of the ways that Svelte helps you build user interfaces with a minimum of fuss. There are plenty of others — for example, [reactive declarations](https://svelte.dev/tutorial/reactive-declarations) essentially do the work of React's `useMemo`, `useCallback` and `useEffect` without the boilerplate (or indeed the garbage collection overhead of creating inline functions and arrays on each state change).
+These are just some of the ways that Svelte helps you build user interfaces with a minimum of fuss. There are plenty of others — for example, [reactive declarations](tutorial/reactive-declarations) essentially do the work of React's `useMemo`, `useCallback` and `useEffect` without the boilerplate (or indeed the garbage collection overhead of creating inline functions and arrays on each state change).
 
 How? By choosing a different set of constraints. Because [Svelte is a compiler](blog/frameworks-without-the-framework), we're not bound to the peculiarities of JavaScript: we can *design* a component authoring experience, rather than having to fit it around the semantics of the language. Paradoxically, this results in *more* idiomatic code — for example using variables naturally rather than via proxies or hooks — while delivering significantly more performant apps.
diff --git a/site/content/docs/01-component-format.md b/site/content/docs/01-component-format.md
index e541292e13..026a2da5b3 100644
--- a/site/content/docs/01-component-format.md
+++ b/site/content/docs/01-component-format.md
@@ -197,7 +197,7 @@ You can `export` bindings from this block, and they will become exports of the c
 
 You cannot `export default`, since the default export is the component itself.
 
-> Variables defined in `module` scripts are not reactive — reassigning them will not trigger a rerender even though the variable itself will update. For values shared between multiple components, consider using a [store](https://svelte.dev/docs#svelte_store).
+> Variables defined in `module` scripts are not reactive — reassigning them will not trigger a rerender even though the variable itself will update. For values shared between multiple components, consider using a [store](docs#svelte_store).
 
 ```html
 <script context="module">

From e959dbcf31fb418b282404daa20c942b2c4264c1 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Wed, 22 Jan 2020 20:26:43 -0500
Subject: [PATCH 28/82] site: add warning to Dockerfile about .dockerignore

---
 site/Dockerfile | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/site/Dockerfile b/site/Dockerfile
index c2a65122d9..0261a69521 100644
--- a/site/Dockerfile
+++ b/site/Dockerfile
@@ -1,3 +1,6 @@
+# IMPORTANT: Don't use this Dockerfile in your own Sapper projects without also looking at the .dockerignore file.
+# Without an appropriate .dockerignore, this Dockerfile will copy a large number of unneeded files into your image.
+
 FROM mhart/alpine-node:12
 
 # install dependencies

From 455a5cc754cbdf605630aceb8dab6bb1281d8a95 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Thu, 23 Jan 2020 10:06:42 -0500
Subject: [PATCH 29/82] fix hydration of <title> (#4311)

---
 CHANGELOG.md                                                | 1 +
 src/compiler/compile/render_ssr/handlers/Title.ts           | 6 +-----
 .../samples/head-meta-hydrate-duplicate/_before_head.html   | 2 +-
 .../samples/head-meta-hydrate-duplicate/_expected-head.html | 2 +-
 4 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5838dcac80..70a4abab9a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@
 * Fix updating a `<slot>` inside an `{#if}` or other block ([#4292](https://github.com/sveltejs/svelte/issues/4292))
 * Fix using RxJS observables in `derived` stores ([#4298](https://github.com/sveltejs/svelte/issues/4298))
 * Add dev mode check to disallow duplicate keys in a keyed `{#each}` ([#4301](https://github.com/sveltejs/svelte/issues/4301))
+* Fix hydration of `<title>` when starting from SSR-generated code with `hydratable: true` ([#4310](https://github.com/sveltejs/svelte/issues/4310))
 
 ## 3.17.2
 
diff --git a/src/compiler/compile/render_ssr/handlers/Title.ts b/src/compiler/compile/render_ssr/handlers/Title.ts
index a3f271ab1b..f1f458ed5b 100644
--- a/src/compiler/compile/render_ssr/handlers/Title.ts
+++ b/src/compiler/compile/render_ssr/handlers/Title.ts
@@ -5,11 +5,7 @@ import { x } from 'code-red';
 export default function(node: Title, renderer: Renderer, options: RenderOptions) {
 	renderer.push();
 
-	renderer.add_string('<title');
-	if (options.hydratable && options.head_id) {
-		renderer.add_string(` data-svelte="${options.head_id}"`);
-	}
-	renderer.add_string('>');
+	renderer.add_string(`<title>`);
 
 	renderer.render(node.children, options);
 
diff --git a/test/hydration/samples/head-meta-hydrate-duplicate/_before_head.html b/test/hydration/samples/head-meta-hydrate-duplicate/_before_head.html
index d2f218fb8d..107753cdd0 100644
--- a/test/hydration/samples/head-meta-hydrate-duplicate/_before_head.html
+++ b/test/hydration/samples/head-meta-hydrate-duplicate/_before_head.html
@@ -1,4 +1,4 @@
-<title data-svelte="svelte-1s8aodm">Some Title</title>
+<title>Some Title</title>
 <link rel="canonical" href="/" data-svelte="svelte-1s8aodm">
 <meta name="description" content="some description" data-svelte="svelte-1s8aodm">
 <meta name="keywords" content="some keywords" data-svelte="svelte-1s8aodm">
\ No newline at end of file
diff --git a/test/server-side-rendering/samples/head-meta-hydrate-duplicate/_expected-head.html b/test/server-side-rendering/samples/head-meta-hydrate-duplicate/_expected-head.html
index d2f218fb8d..107753cdd0 100644
--- a/test/server-side-rendering/samples/head-meta-hydrate-duplicate/_expected-head.html
+++ b/test/server-side-rendering/samples/head-meta-hydrate-duplicate/_expected-head.html
@@ -1,4 +1,4 @@
-<title data-svelte="svelte-1s8aodm">Some Title</title>
+<title>Some Title</title>
 <link rel="canonical" href="/" data-svelte="svelte-1s8aodm">
 <meta name="description" content="some description" data-svelte="svelte-1s8aodm">
 <meta name="keywords" content="some keywords" data-svelte="svelte-1s8aodm">
\ No newline at end of file

From fd9b23e5e469399ef30a34dec9c070bc8eaf42a9 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Thu, 23 Jan 2020 10:07:41 -0500
Subject: [PATCH 30/82] -> v3.17.3

---
 CHANGELOG.md      | 2 +-
 package-lock.json | 2 +-
 package.json      | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 70a4abab9a..a90d456444 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,6 @@
 # Svelte changelog
 
-## Unreleased
+## 3.17.3
 
 * Fix updating a `<slot>` inside an `{#if}` or other block ([#4292](https://github.com/sveltejs/svelte/issues/4292))
 * Fix using RxJS observables in `derived` stores ([#4298](https://github.com/sveltejs/svelte/issues/4298))
diff --git a/package-lock.json b/package-lock.json
index ca225baa1b..cfbc71cdd2 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "svelte",
-  "version": "3.17.2",
+  "version": "3.17.3",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
diff --git a/package.json b/package.json
index 0910dca8c0..2b0b09299b 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "svelte",
-  "version": "3.17.2",
+  "version": "3.17.3",
   "description": "Cybernetically enhanced web apps",
   "module": "index.mjs",
   "main": "index",

From f01bb639be2c832a6813edcd931b1fb886d3b01a Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Thu, 23 Jan 2020 10:40:22 -0500
Subject: [PATCH 31/82] make autosubscribing to a nullish store a no-op (#4304)

* make autosubscribing to a nullish store a no-op (#2181)

* update changelog

* add test
---
 CHANGELOG.md                                        |  1 +
 src/runtime/internal/utils.ts                       |  5 ++++-
 .../samples/store-auto-subscribe-nullish/_config.js | 13 +++++++++++++
 .../store-auto-subscribe-nullish/main.svelte        |  5 +++++
 4 files changed, 23 insertions(+), 1 deletion(-)
 create mode 100644 test/runtime/samples/store-auto-subscribe-nullish/_config.js
 create mode 100644 test/runtime/samples/store-auto-subscribe-nullish/main.svelte

diff --git a/CHANGELOG.md b/CHANGELOG.md
index a90d456444..7ff7d7603b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 ## 3.17.3
 
+* Make autosubscribing to a nullish store a no-op ([#2181](https://github.com/sveltejs/svelte/issues/2181))
 * Fix updating a `<slot>` inside an `{#if}` or other block ([#4292](https://github.com/sveltejs/svelte/issues/4292))
 * Fix using RxJS observables in `derived` stores ([#4298](https://github.com/sveltejs/svelte/issues/4298))
 * Add dev mode check to disallow duplicate keys in a keyed `{#each}` ([#4301](https://github.com/sveltejs/svelte/issues/4301))
diff --git a/src/runtime/internal/utils.ts b/src/runtime/internal/utils.ts
index c7722e1a07..4ba7e18c15 100644
--- a/src/runtime/internal/utils.ts
+++ b/src/runtime/internal/utils.ts
@@ -43,12 +43,15 @@ export function not_equal(a, b) {
 }
 
 export function validate_store(store, name) {
-	if (!store || typeof store.subscribe !== 'function') {
+	if (store != null && typeof store.subscribe !== 'function') {
 		throw new Error(`'${name}' is not a store with a 'subscribe' method`);
 	}
 }
 
 export function subscribe(store, ...callbacks) {
+	if (store == null) {
+		return noop;
+	}
 	const unsub = store.subscribe(...callbacks);
 	return unsub.unsubscribe ? () => unsub.unsubscribe() : unsub;
 }
diff --git a/test/runtime/samples/store-auto-subscribe-nullish/_config.js b/test/runtime/samples/store-auto-subscribe-nullish/_config.js
new file mode 100644
index 0000000000..52e21cef05
--- /dev/null
+++ b/test/runtime/samples/store-auto-subscribe-nullish/_config.js
@@ -0,0 +1,13 @@
+import { writable } from '../../../../store';
+
+export default {
+	html: `
+		<p>undefined</p>
+	`,
+	async test({ assert, component, target }) {
+		component.store = writable('foo');
+		assert.htmlEqual(target.innerHTML, `
+			<p>foo</p>
+		`);
+	}
+};
diff --git a/test/runtime/samples/store-auto-subscribe-nullish/main.svelte b/test/runtime/samples/store-auto-subscribe-nullish/main.svelte
new file mode 100644
index 0000000000..9c1ed4a560
--- /dev/null
+++ b/test/runtime/samples/store-auto-subscribe-nullish/main.svelte
@@ -0,0 +1,5 @@
+<script>
+	export let store;
+</script>
+
+<p>{$store}</p>

From 9cdf0da160d906948a4b4bbaebaf856751906177 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Thu, 23 Jan 2020 10:44:35 -0500
Subject: [PATCH 32/82] fix changelog

---
 CHANGELOG.md | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7ff7d7603b..44253ce59c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,8 +1,11 @@
 # Svelte changelog
 
-## 3.17.3
+## Unreleased
 
 * Make autosubscribing to a nullish store a no-op ([#2181](https://github.com/sveltejs/svelte/issues/2181))
+
+## 3.17.3
+
 * Fix updating a `<slot>` inside an `{#if}` or other block ([#4292](https://github.com/sveltejs/svelte/issues/4292))
 * Fix using RxJS observables in `derived` stores ([#4298](https://github.com/sveltejs/svelte/issues/4298))
 * Add dev mode check to disallow duplicate keys in a keyed `{#each}` ([#4301](https://github.com/sveltejs/svelte/issues/4301))

From bf006a43e5fd2339adb6cfca1a322fdedcbf48da Mon Sep 17 00:00:00 2001
From: Dave Lunny <4298089+himynameisdave@users.noreply.github.com>
Date: Thu, 23 Jan 2020 17:51:29 -0800
Subject: [PATCH 33/82] [Internals] Improve unit tests (#4262)

---
 .github/workflows/ci.yml               | 6 ++++++
 src/compiler/compile/utils/__test__.ts | 4 ++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 2488902b24..14824ecdfa 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -23,3 +23,9 @@ jobs:
     - uses: actions/checkout@v1
     - uses: actions/setup-node@v1
     - run: 'npm i && npm run lint'
+  Unit:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v1
+    - uses: actions/setup-node@v1
+    - run: 'npm i && npm run test:unit'
diff --git a/src/compiler/compile/utils/__test__.ts b/src/compiler/compile/utils/__test__.ts
index 60ad681b47..7777bc6afb 100644
--- a/src/compiler/compile/utils/__test__.ts
+++ b/src/compiler/compile/utils/__test__.ts
@@ -10,7 +10,7 @@ describe('get_name_from_filename', () => {
 		assert.equal(get_name_from_filename('path/to/Widget/index.svelte'), 'Widget');
 	});
 
-	it('handles unusual filenames', () => {
-		assert.equal(get_name_from_filename('path/to/[...parts].svelte'), 'Parts');
+	it('handles Windows filenames', () => {
+		assert.equal(get_name_from_filename('path\\to\\Widget.svelte'), 'Widget');
 	});
 });

From 8e245dc30ea971da953b1806ed980044546a03a9 Mon Sep 17 00:00:00 2001
From: David Kondrad <david.a.kondrad@jci.com>
Date: Sat, 25 Jan 2020 12:21:55 -0500
Subject: [PATCH 34/82] Internals: Scheduler: Fix infinite loop in flush
 (#4316)

---
 src/runtime/internal/scheduler.ts                |  7 ++++---
 .../lifecycle-onmount-infinite-loop/Child.svelte |  1 +
 .../lifecycle-onmount-infinite-loop/_config.js   |  6 ++++++
 .../lifecycle-onmount-infinite-loop/main.svelte  | 16 ++++++++++++++++
 4 files changed, 27 insertions(+), 3 deletions(-)
 create mode 100644 test/runtime/samples/lifecycle-onmount-infinite-loop/Child.svelte
 create mode 100644 test/runtime/samples/lifecycle-onmount-infinite-loop/_config.js
 create mode 100644 test/runtime/samples/lifecycle-onmount-infinite-loop/main.svelte

diff --git a/src/runtime/internal/scheduler.ts b/src/runtime/internal/scheduler.ts
index 04c1264ab1..1ce255b217 100644
--- a/src/runtime/internal/scheduler.ts
+++ b/src/runtime/internal/scheduler.ts
@@ -31,8 +31,8 @@ export function add_flush_callback(fn) {
 	flush_callbacks.push(fn);
 }
 
+const seen_callbacks = new Set();
 export function flush() {
-	const seen_callbacks = new Set();
 
 	do {
 		// first, call beforeUpdate functions
@@ -52,10 +52,10 @@ export function flush() {
 			const callback = render_callbacks[i];
 
 			if (!seen_callbacks.has(callback)) {
-				callback();
-
 				// ...so guard against infinite loops
 				seen_callbacks.add(callback);
+
+				callback();
 			}
 		}
 
@@ -67,6 +67,7 @@ export function flush() {
 	}
 
 	update_scheduled = false;
+	seen_callbacks.clear();
 }
 
 function update($$) {
diff --git a/test/runtime/samples/lifecycle-onmount-infinite-loop/Child.svelte b/test/runtime/samples/lifecycle-onmount-infinite-loop/Child.svelte
new file mode 100644
index 0000000000..ef16875b64
--- /dev/null
+++ b/test/runtime/samples/lifecycle-onmount-infinite-loop/Child.svelte
@@ -0,0 +1 @@
+Child
diff --git a/test/runtime/samples/lifecycle-onmount-infinite-loop/_config.js b/test/runtime/samples/lifecycle-onmount-infinite-loop/_config.js
new file mode 100644
index 0000000000..a76a2686ac
--- /dev/null
+++ b/test/runtime/samples/lifecycle-onmount-infinite-loop/_config.js
@@ -0,0 +1,6 @@
+export default {
+	test({ assert, component }) {
+		const { count } = component;
+		assert.deepEqual(count, 1);
+	}
+};
diff --git a/test/runtime/samples/lifecycle-onmount-infinite-loop/main.svelte b/test/runtime/samples/lifecycle-onmount-infinite-loop/main.svelte
new file mode 100644
index 0000000000..1fa4263e39
--- /dev/null
+++ b/test/runtime/samples/lifecycle-onmount-infinite-loop/main.svelte
@@ -0,0 +1,16 @@
+<script>
+	import { onMount } from 'svelte';
+	import Child from './Child.svelte';
+
+	let root;
+	export let count = 0;
+
+	onMount(() => {
+		if (count < 5) {
+			count++;
+			new Child({ target: root });
+		}
+	});
+</script>
+
+<div bind:this={root}></div>

From 5d4408ba23655c54e8b921e27461273dc5e63610 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Sat, 25 Jan 2020 12:23:50 -0500
Subject: [PATCH 35/82] update changelog

---
 CHANGELOG.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 44253ce59c..b5784f4148 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+* Fix infinite loop when instantiating another component during `onMount` ([#3218](https://github.com/sveltejs/svelte/issues/3218))
 * Make autosubscribing to a nullish store a no-op ([#2181](https://github.com/sveltejs/svelte/issues/2181))
 
 ## 3.17.3

From efe8ab9ca569b8cc706cb4c231b39c160ba479e3 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Sat, 25 Jan 2020 12:26:19 -0500
Subject: [PATCH 36/82] -> v3.18.0

---
 CHANGELOG.md      | 2 +-
 package-lock.json | 2 +-
 package.json      | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index b5784f4148..ed6feef9d4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,6 @@
 # Svelte changelog
 
-## Unreleased
+## 3.18.0
 
 * Fix infinite loop when instantiating another component during `onMount` ([#3218](https://github.com/sveltejs/svelte/issues/3218))
 * Make autosubscribing to a nullish store a no-op ([#2181](https://github.com/sveltejs/svelte/issues/2181))
diff --git a/package-lock.json b/package-lock.json
index cfbc71cdd2..6300fd40ac 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "svelte",
-  "version": "3.17.3",
+  "version": "3.18.0",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
diff --git a/package.json b/package.json
index 2b0b09299b..791327d3f0 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "svelte",
-  "version": "3.17.3",
+  "version": "3.18.0",
   "description": "Cybernetically enhanced web apps",
   "module": "index.mjs",
   "main": "index",

From 3eb298fd28ff68f782f632a9029b430745cb0c2b Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Mon, 27 Jan 2020 14:02:30 -0500
Subject: [PATCH 37/82] fix code generation with adjacent inline and block
 comments (#4327)

---
 CHANGELOG.md      | 4 ++++
 package-lock.json | 6 +++---
 package.json      | 2 +-
 3 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index ed6feef9d4..217651e20b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Svelte changelog
 
+## Unreleased
+
+* Fix code generation error with adjacent inline and block comments ([#4312](https://github.com/sveltejs/svelte/issues/4312))
+
 ## 3.18.0
 
 * Fix infinite loop when instantiating another component during `onMount` ([#3218](https://github.com/sveltejs/svelte/issues/3218))
diff --git a/package-lock.json b/package-lock.json
index 6300fd40ac..5ffb1ba0da 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -597,9 +597,9 @@
       "dev": true
     },
     "code-red": {
-      "version": "0.0.31",
-      "resolved": "https://registry.npmjs.org/code-red/-/code-red-0.0.31.tgz",
-      "integrity": "sha512-7Gf3vm8pDbs+H/hKsaqOZe0xKlE9Neah12GCfs7qun3fBUaOXwexAMjn0Eo9cvJJvhRMaL0jgPiY9ZGLTWoe8A==",
+      "version": "0.0.32",
+      "resolved": "https://registry.npmjs.org/code-red/-/code-red-0.0.32.tgz",
+      "integrity": "sha512-mE+EZc2vJ4HxiejW5S2CvcVDKtopFEmrqAd9DTBDLCNjLgxekPP8wLi/ZiwDTwZwwW3dzeetaubLaMlIvkhVNw==",
       "dev": true,
       "requires": {
         "acorn": "^7.1.0",
diff --git a/package.json b/package.json
index 791327d3f0..3b43d6fa46 100644
--- a/package.json
+++ b/package.json
@@ -70,7 +70,7 @@
     "acorn": "^7.1.0",
     "agadoo": "^1.1.0",
     "c8": "^5.0.1",
-    "code-red": "0.0.31",
+    "code-red": "0.0.32",
     "codecov": "^3.5.0",
     "css-tree": "1.0.0-alpha22",
     "eslint": "^6.3.0",

From 43f19d93a9fe33ec71856d7b080aca1425460a3e Mon Sep 17 00:00:00 2001
From: Wolfr <johan.ronsse@gmail.com>
Date: Mon, 27 Jan 2020 20:28:06 +0100
Subject: [PATCH 38/82] site: Improve open graph images for website (#4328)

---
 site/src/template.html | 1 +
 1 file changed, 1 insertion(+)

diff --git a/site/src/template.html b/site/src/template.html
index dc930a7f72..344684d766 100644
--- a/site/src/template.html
+++ b/site/src/template.html
@@ -15,6 +15,7 @@
 	<meta name='twitter:site' content='@sveltejs'>
 	<meta name='twitter:creator' content='@sveltejs'>
 	<meta name='twitter:image' content='https://svelte.dev/images/twitter-card.png'>
+	<meta name='og:image' content='https://svelte.dev/images/twitter-card.png'>
 
 	<!-- Sapper generates a <style> tag containing critical CSS
 	     for the current page. CSS for the rest of the app is

From ab18f5bb9a678ba9d044f19818232b0d0447e907 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Mon, 27 Jan 2020 14:38:25 -0500
Subject: [PATCH 39/82] site: update Makefile to work without global gcloud
 project setting

---
 site/Makefile | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/site/Makefile b/site/Makefile
index 4c432dc6c9..a16b0a117a 100644
--- a/site/Makefile
+++ b/site/Makefile
@@ -14,9 +14,9 @@ sapper:
 
 docker:
 	@echo "\n~> building docker image"
-	@gcloud builds submit -t $(IMAGE)
+	@gcloud builds submit --project $(PROJECT) -t $(IMAGE)
 
 
 deploy: sapper docker
 	@echo "\n~> deploying $(SERVICE) to Cloud Run servers"
-	@gcloud beta run deploy $(SERVICE) --allow-unauthenticated --platform managed --region us-central1 --image $(IMAGE) --memory=512Mi
+	@gcloud beta run deploy $(SERVICE) --project $(PROJECT) --allow-unauthenticated --platform managed --region us-central1 --image $(IMAGE) --memory=512Mi

From 70d17950880e56f78c0a919b41ad2a356a9e37ff Mon Sep 17 00:00:00 2001
From: Wolfr <johan.ronsse@gmail.com>
Date: Mon, 27 Jan 2020 20:41:18 +0100
Subject: [PATCH 40/82] site: Remove WIP message, but still reference the chat
 room. (#4329)

---
 site/content/docs/00-introduction.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/site/content/docs/00-introduction.md b/site/content/docs/00-introduction.md
index 2456b85f9c..15fdffbde2 100644
--- a/site/content/docs/00-introduction.md
+++ b/site/content/docs/00-introduction.md
@@ -2,8 +2,8 @@
 title: Before we begin
 ---
 
-> Temporary note: This document is a work-in-progress. Please forgive any missing or misleading parts, and don't be shy about asking for help in the [Discord chatroom](chat). The [tutorial](tutorial) is more complete; start there.
-
 This page contains detailed API reference documentation. It's intended to be a resource for people who already have some familiarity with Svelte.
 
 If that's not you (yet), you may prefer to visit the [interactive tutorial](tutorial) or the [examples](examples) before consulting this reference.
+
+Don't be shy about asking for help in the [Discord chatroom](chat).
\ No newline at end of file

From be9b79f805a3f738986dd6a2fc9f39e07efe46bf Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Mon, 27 Jan 2020 18:25:24 -0500
Subject: [PATCH 41/82] fix detection of unused partially global CSS selectors
 (#4332)

---
 CHANGELOG.md                                  |  1 +
 src/compiler/compile/css/Selector.ts          |  2 +-
 .../global-with-unused-descendant/_config.js  | 24 +++++++++++++++++++
 .../expected.css                              |  0
 .../input.svelte                              |  5 ++++
 5 files changed, 31 insertions(+), 1 deletion(-)
 create mode 100644 test/css/samples/global-with-unused-descendant/_config.js
 create mode 100644 test/css/samples/global-with-unused-descendant/expected.css
 create mode 100644 test/css/samples/global-with-unused-descendant/input.svelte

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 217651e20b..8c68dc1068 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@
 ## Unreleased
 
 * Fix code generation error with adjacent inline and block comments ([#4312](https://github.com/sveltejs/svelte/issues/4312))
+* Fix detection of unused CSS selectors that begin with a `:global()` but contain a scoped portion ([#4314](https://github.com/sveltejs/svelte/issues/4314))
 
 ## 3.18.0
 
diff --git a/src/compiler/compile/css/Selector.ts b/src/compiler/compile/css/Selector.ts
index 39bbc2e8d1..6bc046c93e 100644
--- a/src/compiler/compile/css/Selector.ts
+++ b/src/compiler/compile/css/Selector.ts
@@ -32,7 +32,7 @@ export default class Selector {
 		}
 
 		this.local_blocks = this.blocks.slice(0, i);
-		this.used = this.blocks[0].global;
+		this.used = this.local_blocks.length === 0;
 	}
 
 	apply(node: Element, stack: Element[]) {
diff --git a/test/css/samples/global-with-unused-descendant/_config.js b/test/css/samples/global-with-unused-descendant/_config.js
new file mode 100644
index 0000000000..3ed2dd2728
--- /dev/null
+++ b/test/css/samples/global-with-unused-descendant/_config.js
@@ -0,0 +1,24 @@
+export default {
+	warnings: [{
+		code: 'css-unused-selector',
+		end: {
+			character: 27,
+			column: 19,
+			line: 2
+		},
+		frame: `
+			1: <style>
+			2:   :global(.foo) .bar {
+			     ^
+			3:     color: red;
+			4:   }
+		`,
+		message: 'Unused CSS selector',
+		pos: 9,
+		start: {
+			character: 9,
+			column: 1,
+			line: 2
+		}
+	}]
+};
diff --git a/test/css/samples/global-with-unused-descendant/expected.css b/test/css/samples/global-with-unused-descendant/expected.css
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/test/css/samples/global-with-unused-descendant/input.svelte b/test/css/samples/global-with-unused-descendant/input.svelte
new file mode 100644
index 0000000000..ede6eedec3
--- /dev/null
+++ b/test/css/samples/global-with-unused-descendant/input.svelte
@@ -0,0 +1,5 @@
+<style>
+	:global(.foo) .bar {
+		color: red;
+	}
+</style>

From 46634e8ea4933dce04013afdedd793d2f06704e2 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Mon, 27 Jan 2020 18:44:24 -0500
Subject: [PATCH 42/82] -> v3.18.1

---
 CHANGELOG.md      | 2 +-
 package-lock.json | 2 +-
 package.json      | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8c68dc1068..00ea564045 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,6 @@
 # Svelte changelog
 
-## Unreleased
+## 3.18.1
 
 * Fix code generation error with adjacent inline and block comments ([#4312](https://github.com/sveltejs/svelte/issues/4312))
 * Fix detection of unused CSS selectors that begin with a `:global()` but contain a scoped portion ([#4314](https://github.com/sveltejs/svelte/issues/4314))
diff --git a/package-lock.json b/package-lock.json
index 5ffb1ba0da..2872c1b8dd 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "svelte",
-  "version": "3.18.0",
+  "version": "3.18.1",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
diff --git a/package.json b/package.json
index 3b43d6fa46..ff8b819668 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "svelte",
-  "version": "3.18.0",
+  "version": "3.18.1",
   "description": "Cybernetically enhanced web apps",
   "module": "index.mjs",
   "main": "index",

From 3b47e4d4c5613a0182c58342d5d638f34ab25ecc Mon Sep 17 00:00:00 2001
From: Antony Jones <ant@enzy.org>
Date: Tue, 28 Jan 2020 11:41:06 +0000
Subject: [PATCH 43/82] Remove npm module size badge from Readme

Fixes https://github.com/sveltejs/svelte/issues/4333
---
 README.md | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/README.md b/README.md
index 9460efce76..e05154bd7c 100644
--- a/README.md
+++ b/README.md
@@ -7,10 +7,6 @@
     <img src="https://img.shields.io/npm/v/svelte.svg" alt="npm version">
   </a>
 
-  <a href="https://packagephobia.now.sh/result?p=svelte">
-    <img src="https://packagephobia.now.sh/badge?p=svelte" alt="install size">
-  </a>
-
   <a href="https://github.com/sveltejs/svelte/actions">
     <img src="https://github.com/sveltejs/svelte/workflows/CI/badge.svg?branch=master"
          alt="build status">

From 14a3c3a639ca160456fd89433689dbf62200b262 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Tue, 28 Jan 2020 09:04:01 -0500
Subject: [PATCH 44/82] site: update Makefile as 'gcloud beta' is no longer
 necessary

---
 site/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/site/Makefile b/site/Makefile
index a16b0a117a..6fd08fd8ee 100644
--- a/site/Makefile
+++ b/site/Makefile
@@ -19,4 +19,4 @@ docker:
 
 deploy: sapper docker
 	@echo "\n~> deploying $(SERVICE) to Cloud Run servers"
-	@gcloud beta run deploy $(SERVICE) --project $(PROJECT) --allow-unauthenticated --platform managed --region us-central1 --image $(IMAGE) --memory=512Mi
+	@gcloud run deploy $(SERVICE) --project $(PROJECT) --allow-unauthenticated --platform managed --region us-central1 --image $(IMAGE) --memory=512Mi

From 9e7df1e41aef8e62cfc82c45ac4adde17737866f Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Thu, 30 Jan 2020 06:58:31 -0500
Subject: [PATCH 45/82] site: use absolute href to blog feed (#4342)

---
 site/src/routes/blog/index.svelte | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/site/src/routes/blog/index.svelte b/site/src/routes/blog/index.svelte
index 6f96731af0..92fc5ce96d 100644
--- a/site/src/routes/blog/index.svelte
+++ b/site/src/routes/blog/index.svelte
@@ -11,7 +11,7 @@
 
 <svelte:head>
 	<title>Blog • Svelte</title>
-	<link rel="alternate" type="application/rss+xml" title="Svelte blog" href="blog/rss.xml">
+	<link rel="alternate" type="application/rss+xml" title="Svelte blog" href="https://svelte.dev/blog/rss.xml">
 
 	<meta name="twitter:title" content="Svelte blog">
 	<meta name="twitter:description" content="Articles about Svelte and UI development">

From 507661325629ca2b79df9d0103e47d5bd316f8e2 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Thu, 30 Jan 2020 09:25:16 -0500
Subject: [PATCH 46/82] disallow simultaneous foo / {foo} / bind:foo (#4343)

* disallow matching attributes/shorthands/bindings (#4325)

* add tests

* update changelog
---
 CHANGELOG.md                                  |  4 +++
 src/compiler/parse/state/tag.ts               | 31 ++++++++++++-------
 .../attribute-unique-binding-error/error.json | 10 ++++++
 .../input.svelte                              |  1 +
 .../error.json                                | 10 ++++++
 .../input.svelte                              |  1 +
 6 files changed, 46 insertions(+), 11 deletions(-)
 create mode 100644 test/parser/samples/attribute-unique-binding-error/error.json
 create mode 100644 test/parser/samples/attribute-unique-binding-error/input.svelte
 create mode 100644 test/parser/samples/attribute-unique-shorthand-error/error.json
 create mode 100644 test/parser/samples/attribute-unique-shorthand-error/input.svelte

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 00ea564045..10e23686ea 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Svelte changelog
 
+## Unreleased
+
+* Disallow attribute/prop names from matching two-way-bound names or `{shorthand}` attribute/prop names ([#4325](https://github.com/sveltejs/svelte/issues/4325))
+
 ## 3.18.1
 
 * Fix code generation error with adjacent inline and block comments ([#4312](https://github.com/sveltejs/svelte/issues/4312))
diff --git a/src/compiler/parse/state/tag.ts b/src/compiler/parse/state/tag.ts
index c7e761afc2..40bb01de9b 100644
--- a/src/compiler/parse/state/tag.ts
+++ b/src/compiler/parse/state/tag.ts
@@ -288,6 +288,16 @@ function read_tag_name(parser: Parser) {
 function read_attribute(parser: Parser, unique_names: Set<string>) {
 	const start = parser.index;
 
+	function check_unique(name: string) {
+		if (unique_names.has(name)) {
+			parser.error({
+				code: `duplicate-attribute`,
+				message: 'Attributes need to be unique'
+			}, start);
+		}
+		unique_names.add(name);
+	}
+
 	if (parser.eat('{')) {
 		parser.allow_whitespace();
 
@@ -310,6 +320,8 @@ function read_attribute(parser: Parser, unique_names: Set<string>) {
 			parser.allow_whitespace();
 			parser.eat('}', true);
 
+			check_unique(name);
+
 			return {
 				start,
 				end: parser.index,
@@ -341,17 +353,6 @@ function read_attribute(parser: Parser, unique_names: Set<string>) {
 	const colon_index = name.indexOf(':');
 	const type = colon_index !== -1 && get_directive_type(name.slice(0, colon_index));
 
-	if (unique_names.has(name)) {
-		parser.error({
-			code: `duplicate-attribute`,
-			message: 'Attributes need to be unique'
-		}, start);
-	}
-
-	if (type !== "EventHandler") {
-		unique_names.add(name);
-	}
-
 	let value: any[] | true = true;
 	if (parser.eat('=')) {
 		parser.allow_whitespace();
@@ -367,6 +368,12 @@ function read_attribute(parser: Parser, unique_names: Set<string>) {
 	if (type) {
 		const [directive_name, ...modifiers] = name.slice(colon_index + 1).split('|');
 
+		if (type === 'Binding' && directive_name !== 'this') {
+			check_unique(directive_name);
+		} else if (type !== 'EventHandler') {
+			check_unique(name);
+		}
+
 		if (type === 'Ref') {
 			parser.error({
 				code: `invalid-ref-directive`,
@@ -410,6 +417,8 @@ function read_attribute(parser: Parser, unique_names: Set<string>) {
 		return directive;
 	}
 
+	check_unique(name);
+
 	return {
 		start,
 		end,
diff --git a/test/parser/samples/attribute-unique-binding-error/error.json b/test/parser/samples/attribute-unique-binding-error/error.json
new file mode 100644
index 0000000000..dd14572149
--- /dev/null
+++ b/test/parser/samples/attribute-unique-binding-error/error.json
@@ -0,0 +1,10 @@
+{
+	"code": "duplicate-attribute",
+	"message": "Attributes need to be unique",
+	"start": {
+		"line": 1,
+		"column": 17,
+		"character": 17
+	},
+	"pos": 17
+}
diff --git a/test/parser/samples/attribute-unique-binding-error/input.svelte b/test/parser/samples/attribute-unique-binding-error/input.svelte
new file mode 100644
index 0000000000..78f854bad6
--- /dev/null
+++ b/test/parser/samples/attribute-unique-binding-error/input.svelte
@@ -0,0 +1 @@
+<Widget foo={42} bind:foo/>
\ No newline at end of file
diff --git a/test/parser/samples/attribute-unique-shorthand-error/error.json b/test/parser/samples/attribute-unique-shorthand-error/error.json
new file mode 100644
index 0000000000..dd14572149
--- /dev/null
+++ b/test/parser/samples/attribute-unique-shorthand-error/error.json
@@ -0,0 +1,10 @@
+{
+	"code": "duplicate-attribute",
+	"message": "Attributes need to be unique",
+	"start": {
+		"line": 1,
+		"column": 17,
+		"character": 17
+	},
+	"pos": 17
+}
diff --git a/test/parser/samples/attribute-unique-shorthand-error/input.svelte b/test/parser/samples/attribute-unique-shorthand-error/input.svelte
new file mode 100644
index 0000000000..d486eab558
--- /dev/null
+++ b/test/parser/samples/attribute-unique-shorthand-error/input.svelte
@@ -0,0 +1 @@
+<div title='foo' {title}></div>
\ No newline at end of file

From 83d461f53731d566c049a1b071c2b51ee57524b5 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Fri, 31 Jan 2020 14:55:13 -0500
Subject: [PATCH 47/82] site: clarify preserveWhitespace (#4341)

* site: clarify preserveWhitespace

* Update 04-compile-time.md

Co-authored-by: Rich Harris <richard.a.harris@gmail.com>
---
 site/content/docs/04-compile-time.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/site/content/docs/04-compile-time.md b/site/content/docs/04-compile-time.md
index f753b2fcfe..c46cef117d 100644
--- a/site/content/docs/04-compile-time.md
+++ b/site/content/docs/04-compile-time.md
@@ -76,7 +76,7 @@ The following options can be passed to the compiler. None are required:
 | `css` | `true` | If `true`, styles will be included in the JavaScript class and injected at runtime. It's recommended that you set this to `false` and use the CSS that is statically generated, as it will result in smaller JavaScript bundles and better performance.
 | `loopGuardTimeout` | 0 | A `number` that tells Svelte to break the loop if it blocks the thread for more than `loopGuardTimeout` ms. This is useful to prevent infinite loops. **Only available when `dev: true`**
 | `preserveComments` | `false` | If `true`, your HTML comments will be preserved during server-side rendering. By default, they are stripped out.
-| `preserveWhitespace` | `false` | If `true`, whitespace inside and between elements is kept as you typed it, rather than optimised by Svelte.
+| `preserveWhitespace` | `false` | If `true`, whitespace inside and between elements is kept as you typed it, rather than removed or collapsed to a single space where possible.
 | `outputFilename` | `null` | A `string` used for your JavaScript sourcemap.
 | `cssOutputFilename` | `null` | A `string` used for your CSS sourcemap.
 | `sveltePath` | `"svelte"` | The location of the `svelte` package. Any imports from `svelte` or `svelte/[module]` will be modified accordingly.

From 3cbe38cbf1d69e103a490cdb456aa74ab2cfda40 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Mon, 3 Feb 2020 12:12:01 -0500
Subject: [PATCH 48/82] fix binding to module-level variables (#4352)

---
 CHANGELOG.md                                        |  1 +
 src/compiler/compile/render_dom/Renderer.ts         | 13 ++++++++-----
 test/runtime/samples/module-context-bind/_config.js |  4 ++++
 .../runtime/samples/module-context-bind/main.svelte | 11 +++++++++++
 4 files changed, 24 insertions(+), 5 deletions(-)
 create mode 100644 test/runtime/samples/module-context-bind/_config.js
 create mode 100644 test/runtime/samples/module-context-bind/main.svelte

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 10e23686ea..359ab910f5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+* Fix binding to module-level variables ([#4086](https://github.com/sveltejs/svelte/issues/4086))
 * Disallow attribute/prop names from matching two-way-bound names or `{shorthand}` attribute/prop names ([#4325](https://github.com/sveltejs/svelte/issues/4325))
 
 ## 3.18.1
diff --git a/src/compiler/compile/render_dom/Renderer.ts b/src/compiler/compile/render_dom/Renderer.ts
index 046a90b684..8fa36a9120 100644
--- a/src/compiler/compile/render_dom/Renderer.ts
+++ b/src/compiler/compile/render_dom/Renderer.ts
@@ -161,11 +161,14 @@ export default class Renderer {
 		}
 
 		if (
-			variable &&
-			!variable.referenced &&
-			!variable.is_reactive_dependency &&
-			!variable.export_name &&
-			!name.startsWith('$$')
+			variable && (
+				variable.module || (
+					!variable.referenced &&
+					!variable.is_reactive_dependency &&
+					!variable.export_name &&
+					!name.startsWith('$$')
+				)
+			)
 		) {
 			return value || name;
 		}
diff --git a/test/runtime/samples/module-context-bind/_config.js b/test/runtime/samples/module-context-bind/_config.js
new file mode 100644
index 0000000000..32bc9c4ce9
--- /dev/null
+++ b/test/runtime/samples/module-context-bind/_config.js
@@ -0,0 +1,4 @@
+export default {
+	skip_if_ssr: true,
+	html: '<div>object</div>'
+};
diff --git a/test/runtime/samples/module-context-bind/main.svelte b/test/runtime/samples/module-context-bind/main.svelte
new file mode 100644
index 0000000000..1580102bd8
--- /dev/null
+++ b/test/runtime/samples/module-context-bind/main.svelte
@@ -0,0 +1,11 @@
+<script context='module'>
+	let foo;
+</script>
+
+<script>
+	import { onMount } from 'svelte';
+	let bar;
+	onMount(() => bar = foo);
+</script>
+
+<div bind:this={foo}>{typeof bar}</div>

From d78f32ee5a65c6c7cdbaa21eb28d164a1c3a3f92 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Fri, 7 Feb 2020 19:15:40 -0500
Subject: [PATCH 49/82] fix arrow function precedence (#4385)

* update code-red

* fix code-red usage

* update changelog
---
 CHANGELOG.md                                                | 1 +
 package-lock.json                                           | 6 +++---
 package.json                                                | 2 +-
 src/compiler/compile/render_dom/Renderer.ts                 | 2 +-
 src/compiler/compile/render_dom/index.ts                    | 4 ++--
 src/compiler/compile/render_dom/invalidate.ts               | 2 +-
 src/compiler/compile/render_dom/wrappers/AwaitBlock.ts      | 4 ++--
 src/compiler/compile/render_dom/wrappers/Element/Binding.ts | 2 +-
 src/compiler/compile/render_dom/wrappers/Element/index.ts   | 4 ++--
 src/compiler/compile/render_dom/wrappers/MustacheTag.ts     | 2 +-
 src/compiler/compile/render_dom/wrappers/RawMustacheTag.ts  | 2 +-
 src/compiler/compile/render_ssr/handlers/AwaitBlock.ts      | 4 ++--
 src/compiler/compile/render_ssr/handlers/Element.ts         | 2 +-
 src/compiler/compile/render_ssr/handlers/Head.ts            | 2 +-
 src/compiler/compile/render_ssr/handlers/Title.ts           | 2 +-
 15 files changed, 21 insertions(+), 20 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 359ab910f5..a906065883 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@
 
 * Fix binding to module-level variables ([#4086](https://github.com/sveltejs/svelte/issues/4086))
 * Disallow attribute/prop names from matching two-way-bound names or `{shorthand}` attribute/prop names ([#4325](https://github.com/sveltejs/svelte/issues/4325))
+* Fix code generation error with precedence of arrow functions ([#4384](https://github.com/sveltejs/svelte/issues/4384))
 
 ## 3.18.1
 
diff --git a/package-lock.json b/package-lock.json
index 2872c1b8dd..82af35d13f 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -597,9 +597,9 @@
       "dev": true
     },
     "code-red": {
-      "version": "0.0.32",
-      "resolved": "https://registry.npmjs.org/code-red/-/code-red-0.0.32.tgz",
-      "integrity": "sha512-mE+EZc2vJ4HxiejW5S2CvcVDKtopFEmrqAd9DTBDLCNjLgxekPP8wLi/ZiwDTwZwwW3dzeetaubLaMlIvkhVNw==",
+      "version": "0.1.1",
+      "resolved": "https://registry.npmjs.org/code-red/-/code-red-0.1.1.tgz",
+      "integrity": "sha512-2pEIyya4fxI9HxQcrl9dJl20+9He1nLeja50zkf7gK2OTTV9NpD3CgA74gzXnPqWv2zJpa6uXNSaE0haOCpOsw==",
       "dev": true,
       "requires": {
         "acorn": "^7.1.0",
diff --git a/package.json b/package.json
index ff8b819668..4f7acb0fd7 100644
--- a/package.json
+++ b/package.json
@@ -70,7 +70,7 @@
     "acorn": "^7.1.0",
     "agadoo": "^1.1.0",
     "c8": "^5.0.1",
-    "code-red": "0.0.32",
+    "code-red": "0.1.1",
     "codecov": "^3.5.0",
     "css-tree": "1.0.0-alpha22",
     "eslint": "^6.3.0",
diff --git a/src/compiler/compile/render_dom/Renderer.ts b/src/compiler/compile/render_dom/Renderer.ts
index 8fa36a9120..fbb0c76d7d 100644
--- a/src/compiler/compile/render_dom/Renderer.ts
+++ b/src/compiler/compile/render_dom/Renderer.ts
@@ -197,7 +197,7 @@ export default class Renderer {
 
 		return filtered
 			.map(n => x`$$invalidate(${this.context_lookup.get(n).index}, ${n})`)
-			.reduce((lhs, rhs) => x`${lhs}, ${rhs}}`);
+			.reduce((lhs, rhs) => x`${lhs}, ${rhs}`);
 	}
 
 	dirty(names, is_reactive_declaration = false): Expression {
diff --git a/src/compiler/compile/render_dom/index.ts b/src/compiler/compile/render_dom/index.ts
index 26fa4a70f8..a7a55b8843 100644
--- a/src/compiler/compile/render_dom/index.ts
+++ b/src/compiler/compile/render_dom/index.ts
@@ -403,9 +403,9 @@ export default function dom(
 
 				${set && b`$$self.$set = ${set};`}
 
-				${capture_state && x`$$self.$capture_state = ${capture_state};`}
+				${capture_state && b`$$self.$capture_state = ${capture_state};`}
 
-				${inject_state && x`$$self.$inject_state = ${inject_state};`}
+				${inject_state && b`$$self.$inject_state = ${inject_state};`}
 
 				${injected.map(name => b`let ${name};`)}
 
diff --git a/src/compiler/compile/render_dom/invalidate.ts b/src/compiler/compile/render_dom/invalidate.ts
index 65fb73afc3..dc28501863 100644
--- a/src/compiler/compile/render_dom/invalidate.ts
+++ b/src/compiler/compile/render_dom/invalidate.ts
@@ -67,7 +67,7 @@ export function invalidate(renderer: Renderer, scope: Scope, node: Node, names:
 
 			if (head.subscribable && head.reassigned) {
 				const subscribe = `$$subscribe_${head.name}`;
-				invalidate = x`${subscribe}(${invalidate})}`;
+				invalidate = x`${subscribe}(${invalidate})`;
 			}
 
 			return invalidate;
diff --git a/src/compiler/compile/render_dom/wrappers/AwaitBlock.ts b/src/compiler/compile/render_dom/wrappers/AwaitBlock.ts
index 25c5312e65..12b7fc2cef 100644
--- a/src/compiler/compile/render_dom/wrappers/AwaitBlock.ts
+++ b/src/compiler/compile/render_dom/wrappers/AwaitBlock.ts
@@ -205,7 +205,7 @@ export default class AwaitBlockWrapper extends Wrapper {
 
 					} else {
 						const #child_ctx = #ctx.slice();
-						${this.node.value && x`#child_ctx[${value_index}] = ${info}.resolved;`}
+						${this.node.value && b`#child_ctx[${value_index}] = ${info}.resolved;`}
 						${info}.block.p(#child_ctx, #dirty);
 					}
 				`);
@@ -219,7 +219,7 @@ export default class AwaitBlockWrapper extends Wrapper {
 				block.chunks.update.push(b`
 					{
 						const #child_ctx = #ctx.slice();
-						${this.node.value && x`#child_ctx[${value_index}] = ${info}.resolved;`}
+						${this.node.value && b`#child_ctx[${value_index}] = ${info}.resolved;`}
 						${info}.block.p(#child_ctx, #dirty);
 					}
 				`);
diff --git a/src/compiler/compile/render_dom/wrappers/Element/Binding.ts b/src/compiler/compile/render_dom/wrappers/Element/Binding.ts
index 7244d9203d..eca6e9d325 100644
--- a/src/compiler/compile/render_dom/wrappers/Element/Binding.ts
+++ b/src/compiler/compile/render_dom/wrappers/Element/Binding.ts
@@ -97,7 +97,7 @@ export default class BindingWrapper {
 			const type = parent.node.get_static_attribute_value('type');
 
 			if (type === null || type === "" || type === "text" || type === "email" || type === "password") {
-				update_conditions.push(x`(${parent.var}.${this.node.name} !== ${this.snippet})`);
+				update_conditions.push(x`${parent.var}.${this.node.name} !== ${this.snippet}`);
 			}
 		}
 
diff --git a/src/compiler/compile/render_dom/wrappers/Element/index.ts b/src/compiler/compile/render_dom/wrappers/Element/index.ts
index ef33022402..8894308fdf 100644
--- a/src/compiler/compile/render_dom/wrappers/Element/index.ts
+++ b/src/compiler/compile/render_dom/wrappers/Element/index.ts
@@ -415,7 +415,7 @@ export default class ElementWrapper extends Wrapper {
 
 		const is = this.attributes.find(attr => attr.node.name === 'is');
 		if (is) {
-			return x`@element_is("${name}", ${is.render_chunks(block).reduce((lhs, rhs) => x`${lhs} + ${rhs}`)});`;
+			return x`@element_is("${name}", ${is.render_chunks(block).reduce((lhs, rhs) => x`${lhs} + ${rhs}`)})`;
 		}
 
 		return x`@element("${name}")`;
@@ -632,7 +632,7 @@ export default class ElementWrapper extends Wrapper {
 
 	add_this_binding(block: Block, this_binding: Binding) {
 		const { renderer } = this;
-		
+
 		renderer.component.has_reactive_assignments = true;
 
 		const binding_callback = bind_this(renderer.component, block, this_binding.node, this.var);
diff --git a/src/compiler/compile/render_dom/wrappers/MustacheTag.ts b/src/compiler/compile/render_dom/wrappers/MustacheTag.ts
index b5ac6505f8..ea6634ec80 100644
--- a/src/compiler/compile/render_dom/wrappers/MustacheTag.ts
+++ b/src/compiler/compile/render_dom/wrappers/MustacheTag.ts
@@ -17,7 +17,7 @@ export default class MustacheTagWrapper extends Tag {
 	render(block: Block, parent_node: Identifier, parent_nodes: Identifier) {
 		const { init } = this.rename_this_method(
 			block,
-			value => x`@set_data(${this.var}, ${value});`
+			value => x`@set_data(${this.var}, ${value})`
 		);
 
 		block.add_element(
diff --git a/src/compiler/compile/render_dom/wrappers/RawMustacheTag.ts b/src/compiler/compile/render_dom/wrappers/RawMustacheTag.ts
index c6ddde5da2..3b13e6c68a 100644
--- a/src/compiler/compile/render_dom/wrappers/RawMustacheTag.ts
+++ b/src/compiler/compile/render_dom/wrappers/RawMustacheTag.ts
@@ -48,7 +48,7 @@ export default class RawMustacheTagWrapper extends Tag {
 
 			const { init } = this.rename_this_method(
 				block,
-				content => x`${html_tag}.p(${content});`
+				content => x`${html_tag}.p(${content})`
 			);
 
 			const update_anchor = in_head ? 'null' : needs_anchor ? html_anchor : this.next ? this.next.var : 'null';
diff --git a/src/compiler/compile/render_ssr/handlers/AwaitBlock.ts b/src/compiler/compile/render_ssr/handlers/AwaitBlock.ts
index 6dd38bfd2e..f637826280 100644
--- a/src/compiler/compile/render_ssr/handlers/AwaitBlock.ts
+++ b/src/compiler/compile/render_ssr/handlers/AwaitBlock.ts
@@ -12,9 +12,9 @@ export default function(node: AwaitBlock, renderer: Renderer, options: RenderOpt
 	const then = renderer.pop();
 
 	renderer.add_expression(x`
-		(function(__value) {
+		function(__value) {
 			if (@is_promise(__value)) return ${pending};
 			return (function(${node.value}) { return ${then}; }(__value));
-		}(${node.expression.node}))
+		}(${node.expression.node})
 	`);
 }
diff --git a/src/compiler/compile/render_ssr/handlers/Element.ts b/src/compiler/compile/render_ssr/handlers/Element.ts
index e0982a0415..6e6a61974a 100644
--- a/src/compiler/compile/render_ssr/handlers/Element.ts
+++ b/src/compiler/compile/render_ssr/handlers/Element.ts
@@ -65,7 +65,7 @@ export default function(node: Element, renderer: Renderer, options: RenderOption
 			}
 		});
 
-		renderer.add_expression(x`@spread([${args}], ${class_expression});`);
+		renderer.add_expression(x`@spread([${args}], ${class_expression})`);
 	} else {
 		let add_class_attribute = !!class_expression;
 		node.attributes.forEach(attribute => {
diff --git a/src/compiler/compile/render_ssr/handlers/Head.ts b/src/compiler/compile/render_ssr/handlers/Head.ts
index 456e5c279b..cf1e6bd555 100644
--- a/src/compiler/compile/render_ssr/handlers/Head.ts
+++ b/src/compiler/compile/render_ssr/handlers/Head.ts
@@ -12,5 +12,5 @@ export default function(node: Head, renderer: Renderer, options: RenderOptions)
 	renderer.render(node.children, head_options);
 	const result = renderer.pop();
 
-	renderer.add_expression(x`($$result.head += ${result}, "")`);
+	renderer.add_expression(x`$$result.head += ${result}, ""`);
 }
diff --git a/src/compiler/compile/render_ssr/handlers/Title.ts b/src/compiler/compile/render_ssr/handlers/Title.ts
index f1f458ed5b..c4c7897185 100644
--- a/src/compiler/compile/render_ssr/handlers/Title.ts
+++ b/src/compiler/compile/render_ssr/handlers/Title.ts
@@ -12,5 +12,5 @@ export default function(node: Title, renderer: Renderer, options: RenderOptions)
 	renderer.add_string(`</title>`);
 	const result = renderer.pop();
 
-	renderer.add_expression(x`($$result.title = ${result}, "")`);
+	renderer.add_expression(x`$$result.title = ${result}, ""`);
 }

From 12a9ff2ac15562647722ffe095e601cf14f822f8 Mon Sep 17 00:00:00 2001
From: Christian Kaisermann <christian@kaisermann.me>
Date: Fri, 7 Feb 2020 21:25:35 -0300
Subject: [PATCH 50/82] chore: fix .eslintignore and remove .prettierrc (#4378)

---
 .eslintignore | 3 +++
 .prettierrc   | 3 ---
 2 files changed, 3 insertions(+), 3 deletions(-)
 delete mode 100644 .prettierrc

diff --git a/.eslintignore b/.eslintignore
index bfe7b1fa95..b5cb03ae6e 100644
--- a/.eslintignore
+++ b/.eslintignore
@@ -4,6 +4,9 @@ _output
 test/*/samples/*/output.js
 node_modules
 
+# automatically generated
+internal_exports.ts
+
 # output files
 animate/*.js
 esing/*.js
diff --git a/.prettierrc b/.prettierrc
deleted file mode 100644
index 81451039fa..0000000000
--- a/.prettierrc
+++ /dev/null
@@ -1,3 +0,0 @@
-useTabs: true
-singleQuote: true
-trailingComma: es5

From a40f4ad5e315bab5569d98c48a818cf3bbadc3a3 Mon Sep 17 00:00:00 2001
From: Christian Heine <40512168+christianheine@users.noreply.github.com>
Date: Sat, 8 Feb 2020 08:27:28 +0800
Subject: [PATCH 51/82] npm audit fix related to https-proxy-agent (#4359)

---
 package-lock.json | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/package-lock.json b/package-lock.json
index 82af35d13f..73f49c08e8 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1682,9 +1682,9 @@
       }
     },
     "https-proxy-agent": {
-      "version": "2.2.2",
-      "resolved": "https://registry.npmjs.org/https-proxy-agent/-/https-proxy-agent-2.2.2.tgz",
-      "integrity": "sha512-c8Ndjc9Bkpfx/vCJueCPy0jlP4ccCCSNDp8xwCZzPjKJUm+B+u9WX2x98Qx4n1PiMNTWo3D7KK5ifNV/yJyRzg==",
+      "version": "2.2.4",
+      "resolved": "https://registry.npmjs.org/https-proxy-agent/-/https-proxy-agent-2.2.4.tgz",
+      "integrity": "sha512-OmvfoQ53WLjtA9HeYP9RNrWMJzzAz1JGaSFr1nijg0PVR1JaD/xbJq1mdEIIlxGpXp9eSe/O2LgU9DJmTPd0Eg==",
       "dev": true,
       "requires": {
         "agent-base": "^4.3.0",

From 4b04b16fe060cc00224bbff93ad9c345c390132e Mon Sep 17 00:00:00 2001
From: Jordan Gensler <jordangens@gmail.com>
Date: Sat, 8 Feb 2020 06:22:38 -0800
Subject: [PATCH 52/82] avoid using .shift() in flush() (#4356)

---
 src/runtime/internal/scheduler.ts | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/runtime/internal/scheduler.ts b/src/runtime/internal/scheduler.ts
index 1ce255b217..b0db71035a 100644
--- a/src/runtime/internal/scheduler.ts
+++ b/src/runtime/internal/scheduler.ts
@@ -31,18 +31,23 @@ export function add_flush_callback(fn) {
 	flush_callbacks.push(fn);
 }
 
+let flushing = false;
 const seen_callbacks = new Set();
 export function flush() {
+	if (flushing) return;
+	flushing = true;
 
 	do {
 		// first, call beforeUpdate functions
 		// and update components
-		while (dirty_components.length) {
-			const component = dirty_components.shift();
+		for (let i = 0; i < dirty_components.length; i += 1) {
+			const component = dirty_components[i];
 			set_current_component(component);
 			update(component.$$);
 		}
 
+		dirty_components.length = 0;
+
 		while (binding_callbacks.length) binding_callbacks.pop()();
 
 		// then, once components are updated, call
@@ -67,6 +72,7 @@ export function flush() {
 	}
 
 	update_scheduled = false;
+	flushing = false;
 	seen_callbacks.clear();
 }
 

From cb67a53e51b4859debefb720aceb4d3255a76967 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Sat, 8 Feb 2020 09:24:13 -0500
Subject: [PATCH 53/82] update changelog

---
 CHANGELOG.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index a906065883..899e0d5b83 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@
 
 * Fix binding to module-level variables ([#4086](https://github.com/sveltejs/svelte/issues/4086))
 * Disallow attribute/prop names from matching two-way-bound names or `{shorthand}` attribute/prop names ([#4325](https://github.com/sveltejs/svelte/issues/4325))
+* Improve performance of `flush()` by not using `.shift()` ([#4356](https://github.com/sveltejs/svelte/pull/4356))
 * Fix code generation error with precedence of arrow functions ([#4384](https://github.com/sveltejs/svelte/issues/4384))
 
 ## 3.18.1

From 2195832ecce1bb179162806e983a8c29412fead9 Mon Sep 17 00:00:00 2001
From: Tan Li Hau <tanhauhau@users.noreply.github.com>
Date: Sun, 9 Feb 2020 12:59:43 +0800
Subject: [PATCH 54/82] better error messages for else, elseif, then, catch
 with unclosed tag (#4136)

---
 CHANGELOG.md                                  |   1 +
 src/compiler/parse/state/mustache.ts          |  20 +-
 src/compiler/parse/utils/node.ts              |  30 +++
 .../error-catch-before-closing/error.json     |   6 +
 .../error-catch-before-closing/input.svelte   |   4 +
 .../error-else-before-closing-2/error.json    |   6 +
 .../error-else-before-closing-2/input.svelte  |   4 +
 .../error-else-before-closing-3/error.json    |   6 +
 .../error-else-before-closing-3/input.svelte  |   2 +
 .../error-else-before-closing/error.json      |   6 +
 .../error-else-before-closing/input.svelte    |   4 +
 .../error-else-if-before-closing-2/error.json |   6 +
 .../input.svelte                              |   4 +
 .../error-else-if-before-closing/error.json   |   6 +
 .../error-else-if-before-closing/input.svelte |   4 +
 .../error-else-if-without-if/error.json       |   6 +
 .../error-else-if-without-if/input.svelte     |   4 +
 .../error-then-before-closing/error.json      |   6 +
 .../error-then-before-closing/input.svelte    |   4 +
 .../no-error-if-before-closing/input.svelte   |  19 ++
 .../no-error-if-before-closing/output.json    | 218 ++++++++++++++++++
 21 files changed, 361 insertions(+), 5 deletions(-)
 create mode 100644 src/compiler/parse/utils/node.ts
 create mode 100644 test/parser/samples/error-catch-before-closing/error.json
 create mode 100644 test/parser/samples/error-catch-before-closing/input.svelte
 create mode 100644 test/parser/samples/error-else-before-closing-2/error.json
 create mode 100644 test/parser/samples/error-else-before-closing-2/input.svelte
 create mode 100644 test/parser/samples/error-else-before-closing-3/error.json
 create mode 100644 test/parser/samples/error-else-before-closing-3/input.svelte
 create mode 100644 test/parser/samples/error-else-before-closing/error.json
 create mode 100644 test/parser/samples/error-else-before-closing/input.svelte
 create mode 100644 test/parser/samples/error-else-if-before-closing-2/error.json
 create mode 100644 test/parser/samples/error-else-if-before-closing-2/input.svelte
 create mode 100644 test/parser/samples/error-else-if-before-closing/error.json
 create mode 100644 test/parser/samples/error-else-if-before-closing/input.svelte
 create mode 100644 test/parser/samples/error-else-if-without-if/error.json
 create mode 100644 test/parser/samples/error-else-if-without-if/input.svelte
 create mode 100644 test/parser/samples/error-then-before-closing/error.json
 create mode 100644 test/parser/samples/error-then-before-closing/input.svelte
 create mode 100644 test/parser/samples/no-error-if-before-closing/input.svelte
 create mode 100644 test/parser/samples/no-error-if-before-closing/output.json

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 899e0d5b83..6337653fb1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@
 ## Unreleased
 
 * Fix binding to module-level variables ([#4086](https://github.com/sveltejs/svelte/issues/4086))
+* Improve parsing error messages when there is a pending unclosed tag ([#4131](https://github.com/sveltejs/svelte/issues/4131))
 * Disallow attribute/prop names from matching two-way-bound names or `{shorthand}` attribute/prop names ([#4325](https://github.com/sveltejs/svelte/issues/4325))
 * Improve performance of `flush()` by not using `.shift()` ([#4356](https://github.com/sveltejs/svelte/pull/4356))
 * Fix code generation error with precedence of arrow functions ([#4384](https://github.com/sveltejs/svelte/issues/4384))
diff --git a/src/compiler/parse/state/mustache.ts b/src/compiler/parse/state/mustache.ts
index 140e722b10..e5e365dddf 100644
--- a/src/compiler/parse/state/mustache.ts
+++ b/src/compiler/parse/state/mustache.ts
@@ -3,6 +3,7 @@ import read_expression from '../read/expression';
 import { closing_tag_omitted } from '../utils/html';
 import { whitespace } from '../../utils/patterns';
 import { trim_start, trim_end } from '../../utils/trim';
+import { to_string } from '../utils/node';
 import { Parser } from '../index';
 import { TemplateNode } from '../../interfaces';
 
@@ -106,11 +107,14 @@ export default function mustache(parser: Parser) {
 		// :else if
 		if (parser.eat('if')) {
 			const block = parser.current();
-			if (block.type !== 'IfBlock')
+			if (block.type !== 'IfBlock') {
 				parser.error({
 					code: `invalid-elseif-placement`,
-					message: 'Cannot have an {:else if ...} block outside an {#if ...} block'
+					message: parser.stack.some(block => block.type === 'IfBlock')
+						? `Expected to close ${to_string(block)} before seeing {:else if ...} block`
+						: `Cannot have an {:else if ...} block outside an {#if ...} block`
 				});
+			}
 
 			parser.require_whitespace();
 
@@ -144,7 +148,9 @@ export default function mustache(parser: Parser) {
 			if (block.type !== 'IfBlock' && block.type !== 'EachBlock') {
 				parser.error({
 					code: `invalid-else-placement`,
-					message: 'Cannot have an {:else} block outside an {#if ...} or {#each ...} block'
+					message: parser.stack.some(block => block.type === 'IfBlock' || block.type === 'EachBlock')
+						? `Expected to close ${to_string(block)} before seeing {:else} block`
+						: `Cannot have an {:else} block outside an {#if ...} or {#each ...} block`
 				});
 			}
 
@@ -168,14 +174,18 @@ export default function mustache(parser: Parser) {
 			if (block.type !== 'PendingBlock') {
 				parser.error({
 					code: `invalid-then-placement`,
-					message: 'Cannot have an {:then} block outside an {#await ...} block'
+					message: parser.stack.some(block => block.type === 'PendingBlock')
+						? `Expected to close ${to_string(block)} before seeing {:then} block`
+						: `Cannot have an {:then} block outside an {#await ...} block`
 				});
 			}
 		} else {
 			if (block.type !== 'ThenBlock' && block.type !== 'PendingBlock') {
 				parser.error({
 					code: `invalid-catch-placement`,
-					message: 'Cannot have an {:catch} block outside an {#await ...} block'
+					message: parser.stack.some(block => block.type === 'ThenBlock' || block.type === 'PendingBlock')
+						? `Expected to close ${to_string(block)} before seeing {:catch} block`
+						: `Cannot have an {:catch} block outside an {#await ...} block`
 				});
 			}
 		}
diff --git a/src/compiler/parse/utils/node.ts b/src/compiler/parse/utils/node.ts
new file mode 100644
index 0000000000..0d39529b59
--- /dev/null
+++ b/src/compiler/parse/utils/node.ts
@@ -0,0 +1,30 @@
+import { TemplateNode } from '../../interfaces';
+
+export function to_string(node: TemplateNode) {
+	switch (node.type) {
+		case 'IfBlock':
+			return '{#if} block';
+		case 'ThenBlock':
+			return '{:then} block';
+		case 'ElseBlock':
+			return '{:else} block';
+		case 'PendingBlock':
+		case 'AwaitBlock':
+			return '{#await} block';
+		case 'CatchBlock':
+			return '{:catch} block';
+		case 'EachBlock':
+			return '{#each} block';
+		case 'RawMustacheTag':
+			return '{@html} block';
+		case 'DebugTag':
+			return '{@debug} block';
+		case 'Element':
+		case 'InlineComponent':
+		case 'Slot':
+		case 'Title':
+			return `<${node.name}> tag`;
+		default:
+			return node.type;
+	}
+}
diff --git a/test/parser/samples/error-catch-before-closing/error.json b/test/parser/samples/error-catch-before-closing/error.json
new file mode 100644
index 0000000000..30fbf5fbd5
--- /dev/null
+++ b/test/parser/samples/error-catch-before-closing/error.json
@@ -0,0 +1,6 @@
+{
+	"code": "invalid-catch-placement",
+	"message": "Expected to close {#each} block before seeing {:catch} block",
+	"start": { "line": 3, "column": 7, "character": 41 },
+	"pos": 41
+}
diff --git a/test/parser/samples/error-catch-before-closing/input.svelte b/test/parser/samples/error-catch-before-closing/input.svelte
new file mode 100644
index 0000000000..bd771701e2
--- /dev/null
+++ b/test/parser/samples/error-catch-before-closing/input.svelte
@@ -0,0 +1,4 @@
+{#await true}
+	{#each foo as bar}
+{:catch f}
+{/await}
\ No newline at end of file
diff --git a/test/parser/samples/error-else-before-closing-2/error.json b/test/parser/samples/error-else-before-closing-2/error.json
new file mode 100644
index 0000000000..d35be1abf5
--- /dev/null
+++ b/test/parser/samples/error-else-before-closing-2/error.json
@@ -0,0 +1,6 @@
+{
+	"code": "invalid-else-placement",
+	"message": "Expected to close {#await} block before seeing {:else} block",
+	"start": { "line": 3, "column": 6, "character": 29 },
+	"pos": 29
+}
diff --git a/test/parser/samples/error-else-before-closing-2/input.svelte b/test/parser/samples/error-else-before-closing-2/input.svelte
new file mode 100644
index 0000000000..f865a9a533
--- /dev/null
+++ b/test/parser/samples/error-else-before-closing-2/input.svelte
@@ -0,0 +1,4 @@
+{#if true}
+	{#await p}
+{:else}
+{/if}
\ No newline at end of file
diff --git a/test/parser/samples/error-else-before-closing-3/error.json b/test/parser/samples/error-else-before-closing-3/error.json
new file mode 100644
index 0000000000..e5ec210c75
--- /dev/null
+++ b/test/parser/samples/error-else-before-closing-3/error.json
@@ -0,0 +1,6 @@
+{
+	"code": "invalid-else-placement",
+	"message": "Cannot have an {:else} block outside an {#if ...} or {#each ...} block",
+	"start": { "line": 2, "column": 6, "character": 11 },
+	"pos": 11
+}
diff --git a/test/parser/samples/error-else-before-closing-3/input.svelte b/test/parser/samples/error-else-before-closing-3/input.svelte
new file mode 100644
index 0000000000..fb434f26a3
--- /dev/null
+++ b/test/parser/samples/error-else-before-closing-3/input.svelte
@@ -0,0 +1,2 @@
+<li>
+{:else}
\ No newline at end of file
diff --git a/test/parser/samples/error-else-before-closing/error.json b/test/parser/samples/error-else-before-closing/error.json
new file mode 100644
index 0000000000..5b6e490c0f
--- /dev/null
+++ b/test/parser/samples/error-else-before-closing/error.json
@@ -0,0 +1,6 @@
+{
+	"code": "invalid-else-placement",
+	"message": "Expected to close <li> tag before seeing {:else} block",
+	"start": { "line": 3, "column": 6, "character": 23 },
+	"pos": 23
+}
diff --git a/test/parser/samples/error-else-before-closing/input.svelte b/test/parser/samples/error-else-before-closing/input.svelte
new file mode 100644
index 0000000000..a22863192d
--- /dev/null
+++ b/test/parser/samples/error-else-before-closing/input.svelte
@@ -0,0 +1,4 @@
+{#if true}
+	<li>
+{:else}
+{/if}
\ No newline at end of file
diff --git a/test/parser/samples/error-else-if-before-closing-2/error.json b/test/parser/samples/error-else-if-before-closing-2/error.json
new file mode 100644
index 0000000000..e55f4f11e5
--- /dev/null
+++ b/test/parser/samples/error-else-if-before-closing-2/error.json
@@ -0,0 +1,6 @@
+{
+	"code": "invalid-elseif-placement",
+	"message": "Expected to close <p> tag before seeing {:else if ...} block",
+	"start": { "line": 3, "column": 9, "character": 25 },
+	"pos": 25
+}
diff --git a/test/parser/samples/error-else-if-before-closing-2/input.svelte b/test/parser/samples/error-else-if-before-closing-2/input.svelte
new file mode 100644
index 0000000000..5ae36df4eb
--- /dev/null
+++ b/test/parser/samples/error-else-if-before-closing-2/input.svelte
@@ -0,0 +1,4 @@
+{#if true}
+	<p>
+{:else if false}
+{/if}
\ No newline at end of file
diff --git a/test/parser/samples/error-else-if-before-closing/error.json b/test/parser/samples/error-else-if-before-closing/error.json
new file mode 100644
index 0000000000..21d16c72a4
--- /dev/null
+++ b/test/parser/samples/error-else-if-before-closing/error.json
@@ -0,0 +1,6 @@
+{
+	"code": "invalid-elseif-placement",
+	"message": "Expected to close {#await} block before seeing {:else if ...} block",
+	"start": { "line": 3, "column": 9, "character": 34 },
+	"pos": 34
+}
diff --git a/test/parser/samples/error-else-if-before-closing/input.svelte b/test/parser/samples/error-else-if-before-closing/input.svelte
new file mode 100644
index 0000000000..486a921a9a
--- /dev/null
+++ b/test/parser/samples/error-else-if-before-closing/input.svelte
@@ -0,0 +1,4 @@
+{#if true}
+	{#await foo}
+{:else if false}
+{/if}
\ No newline at end of file
diff --git a/test/parser/samples/error-else-if-without-if/error.json b/test/parser/samples/error-else-if-without-if/error.json
new file mode 100644
index 0000000000..dd69df6772
--- /dev/null
+++ b/test/parser/samples/error-else-if-without-if/error.json
@@ -0,0 +1,6 @@
+{
+	"code": "invalid-elseif-placement",
+	"message": "Cannot have an {:else if ...} block outside an {#if ...} block",
+	"start": { "line": 3, "column": 10, "character": 35 },
+	"pos": 35
+}
diff --git a/test/parser/samples/error-else-if-without-if/input.svelte b/test/parser/samples/error-else-if-without-if/input.svelte
new file mode 100644
index 0000000000..06baf33511
--- /dev/null
+++ b/test/parser/samples/error-else-if-without-if/input.svelte
@@ -0,0 +1,4 @@
+{#await foo}
+{:then bar}
+	{:else if}
+{/await}
\ No newline at end of file
diff --git a/test/parser/samples/error-then-before-closing/error.json b/test/parser/samples/error-then-before-closing/error.json
new file mode 100644
index 0000000000..07310c93fa
--- /dev/null
+++ b/test/parser/samples/error-then-before-closing/error.json
@@ -0,0 +1,6 @@
+{
+	"code": "invalid-then-placement",
+	"message": "Expected to close <li> tag before seeing {:then} block",
+	"start": { "line": 3, "column": 6, "character": 26 },
+	"pos": 26
+}
diff --git a/test/parser/samples/error-then-before-closing/input.svelte b/test/parser/samples/error-then-before-closing/input.svelte
new file mode 100644
index 0000000000..bb0b993bdf
--- /dev/null
+++ b/test/parser/samples/error-then-before-closing/input.svelte
@@ -0,0 +1,4 @@
+{#await true}
+	<li>
+{:then f}
+{/await}
\ No newline at end of file
diff --git a/test/parser/samples/no-error-if-before-closing/input.svelte b/test/parser/samples/no-error-if-before-closing/input.svelte
new file mode 100644
index 0000000000..4059e0d4d1
--- /dev/null
+++ b/test/parser/samples/no-error-if-before-closing/input.svelte
@@ -0,0 +1,19 @@
+{#if true}
+	<input>
+{:else}
+{/if}
+
+{#if true}
+	<br>
+{:else}
+{/if}
+
+{#await true}
+	<input>
+{:then f}
+{/await}
+
+{#await true}
+	<br>
+{:then f}
+{/await}
\ No newline at end of file
diff --git a/test/parser/samples/no-error-if-before-closing/output.json b/test/parser/samples/no-error-if-before-closing/output.json
new file mode 100644
index 0000000000..ad8ccd0f91
--- /dev/null
+++ b/test/parser/samples/no-error-if-before-closing/output.json
@@ -0,0 +1,218 @@
+{
+	"html": {
+		"start": 0,
+		"end": 148,
+		"type": "Fragment",
+		"children": [
+			{
+				"start": 0,
+				"end": 33,
+				"type": "IfBlock",
+				"expression": {
+					"type": "Literal",
+					"start": 5,
+					"end": 9,
+					"value": true,
+					"raw": "true"
+				},
+				"children": [
+					{
+						"start": 12,
+						"end": 19,
+						"type": "Element",
+						"name": "input",
+						"attributes": [],
+						"children": []
+					}
+				],
+				"else": {
+					"start": 27,
+					"end": 28,
+					"type": "ElseBlock",
+					"children": []
+				}
+			},
+			{
+				"start": 33,
+				"end": 35,
+				"type": "Text",
+				"raw": "\n\n",
+				"data": "\n\n"
+			},
+			{
+				"start": 35,
+				"end": 65,
+				"type": "IfBlock",
+				"expression": {
+					"type": "Literal",
+					"start": 40,
+					"end": 44,
+					"value": true,
+					"raw": "true"
+				},
+				"children": [
+					{
+						"start": 47,
+						"end": 51,
+						"type": "Element",
+						"name": "br",
+						"attributes": [],
+						"children": []
+					}
+				],
+				"else": {
+					"start": 59,
+					"end": 60,
+					"type": "ElseBlock",
+					"children": []
+				}
+			},
+			{
+				"start": 65,
+				"end": 67,
+				"type": "Text",
+				"raw": "\n\n",
+				"data": "\n\n"
+			},
+			{
+				"start": 67,
+				"end": 108,
+				"type": "AwaitBlock",
+				"expression": {
+					"type": "Literal",
+					"start": 75,
+					"end": 79,
+					"value": true,
+					"raw": "true"
+				},
+				"value": "f",
+				"error": null,
+				"pending": {
+					"start": 80,
+					"end": 90,
+					"type": "PendingBlock",
+					"children": [
+						{
+							"start": 80,
+							"end": 82,
+							"type": "Text",
+							"raw": "\n\t",
+							"data": "\n\t"
+						},
+						{
+							"start": 82,
+							"end": 89,
+							"type": "Element",
+							"name": "input",
+							"attributes": [],
+							"children": []
+						},
+						{
+							"start": 89,
+							"end": 90,
+							"type": "Text",
+							"raw": "\n",
+							"data": "\n"
+						}
+					],
+					"skip": false
+				},
+				"then": {
+					"start": 90,
+					"end": 100,
+					"type": "ThenBlock",
+					"children": [
+						{
+							"start": 99,
+							"end": 100,
+							"type": "Text",
+							"raw": "\n",
+							"data": "\n"
+						}
+					],
+					"skip": false
+				},
+				"catch": {
+					"start": null,
+					"end": null,
+					"type": "CatchBlock",
+					"children": [],
+					"skip": true
+				}
+			},
+			{
+				"start": 108,
+				"end": 110,
+				"type": "Text",
+				"raw": "\n\n",
+				"data": "\n\n"
+			},
+			{
+				"start": 110,
+				"end": 148,
+				"type": "AwaitBlock",
+				"expression": {
+					"type": "Literal",
+					"start": 118,
+					"end": 122,
+					"value": true,
+					"raw": "true"
+				},
+				"value": "f",
+				"error": null,
+				"pending": {
+					"start": 123,
+					"end": 130,
+					"type": "PendingBlock",
+					"children": [
+						{
+							"start": 123,
+							"end": 125,
+							"type": "Text",
+							"raw": "\n\t",
+							"data": "\n\t"
+						},
+						{
+							"start": 125,
+							"end": 129,
+							"type": "Element",
+							"name": "br",
+							"attributes": [],
+							"children": []
+						},
+						{
+							"start": 129,
+							"end": 130,
+							"type": "Text",
+							"raw": "\n",
+							"data": "\n"
+						}
+					],
+					"skip": false
+				},
+				"then": {
+					"start": 130,
+					"end": 140,
+					"type": "ThenBlock",
+					"children": [
+						{
+							"start": 139,
+							"end": 140,
+							"type": "Text",
+							"raw": "\n",
+							"data": "\n"
+						}
+					],
+					"skip": false
+				},
+				"catch": {
+					"start": null,
+					"end": null,
+					"type": "CatchBlock",
+					"children": [],
+					"skip": true
+				}
+			}
+		]
+	}
+}
\ No newline at end of file

From f5f489984f49b2442e48e667e9634f1ef90e36d8 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Sun, 9 Feb 2020 00:04:21 -0500
Subject: [PATCH 55/82] fix handling of reserved keywords when parsing (#4390)

---
 CHANGELOG.md                                  |  2 +
 src/compiler/parse/index.ts                   |  4 +-
 src/compiler/parse/read/context.ts            | 22 +++++++++--
 src/compiler/parse/read/expression.ts         | 30 +--------------
 .../action-with-identifier/output.json        | 10 +++++
 .../attribute-dynamic-boolean/output.json     | 10 +++++
 .../attribute-dynamic-reserved/input.svelte   |  1 -
 .../attribute-dynamic-reserved/output.json    | 37 -------------------
 .../samples/attribute-dynamic/output.json     | 20 ++++++++++
 .../attribute-with-whitespace/output.json     | 10 +++++
 test/parser/samples/binding/output.json       | 10 +++++
 .../each-block-destructured/output.json       | 20 ++++++++++
 .../samples/each-block-else/output.json       | 10 +++++
 .../samples/each-block-indexed/output.json    | 20 ++++++++++
 .../samples/each-block-keyed/output.json      | 10 +++++
 test/parser/samples/each-block/output.json    | 10 +++++
 .../samples/element-with-mustache/output.json | 10 +++++
 test/parser/samples/event-handler/output.json | 10 +++++
 test/parser/samples/if-block-else/output.json | 10 +++++
 test/parser/samples/if-block/output.json      | 10 +++++
 .../implicitly-closed-li-block/output.json    | 10 +++++
 test/parser/samples/refs/output.json          | 10 +++++
 .../output.json                               | 10 +++++
 .../script-comment-trailing/output.json       | 10 +++++
 test/parser/samples/script/output.json        | 10 +++++
 .../space-between-mustaches/output.json       | 30 +++++++++++++++
 test/parser/samples/spread/output.json        | 10 +++++
 .../samples/textarea-children/output.json     | 10 +++++
 .../samples/whitespace-normal/output.json     | 10 +++++
 test/parser/samples/yield/input.svelte        |  1 -
 test/parser/samples/yield/output.json         | 20 ----------
 .../_config.js                                |  5 +++
 .../main.svelte                               |  7 ++++
 .../errors.json                               | 15 ++++++++
 .../input.svelte                              |  3 ++
 35 files changed, 333 insertions(+), 94 deletions(-)
 delete mode 100644 test/parser/samples/attribute-dynamic-reserved/input.svelte
 delete mode 100644 test/parser/samples/attribute-dynamic-reserved/output.json
 delete mode 100644 test/parser/samples/yield/input.svelte
 delete mode 100644 test/parser/samples/yield/output.json
 create mode 100644 test/runtime/samples/each-block-destructured-object-reserved-key/_config.js
 create mode 100644 test/runtime/samples/each-block-destructured-object-reserved-key/main.svelte
 create mode 100644 test/validator/samples/each-block-invalid-context-destructured-object/errors.json
 create mode 100644 test/validator/samples/each-block-invalid-context-destructured-object/input.svelte

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6337653fb1..16e6484ab3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,8 @@
 * Improve parsing error messages when there is a pending unclosed tag ([#4131](https://github.com/sveltejs/svelte/issues/4131))
 * Disallow attribute/prop names from matching two-way-bound names or `{shorthand}` attribute/prop names ([#4325](https://github.com/sveltejs/svelte/issues/4325))
 * Improve performance of `flush()` by not using `.shift()` ([#4356](https://github.com/sveltejs/svelte/pull/4356))
+* Permit reserved keywords as destructuring keys in `{#each}` ([#4372](https://github.com/sveltejs/svelte/issues/4372))
+* Disallow reserved keywords in `{expressions}` ([#4372](https://github.com/sveltejs/svelte/issues/4372))
 * Fix code generation error with precedence of arrow functions ([#4384](https://github.com/sveltejs/svelte/issues/4384))
 
 ## 3.18.1
diff --git a/src/compiler/parse/index.ts b/src/compiler/parse/index.ts
index e552374698..a809eeebeb 100644
--- a/src/compiler/parse/index.ts
+++ b/src/compiler/parse/index.ts
@@ -141,7 +141,7 @@ export class Parser {
 		return result;
 	}
 
-	read_identifier() {
+	read_identifier(allow_reserved = false) {
 		const start = this.index;
 
 		let i = this.index;
@@ -160,7 +160,7 @@ export class Parser {
 
 		const identifier = this.template.slice(this.index, this.index = i);
 
-		if (reserved.has(identifier)) {
+		if (!allow_reserved && reserved.has(identifier)) {
 			this.error({
 				code: `unexpected-reserved-word`,
 				message: `'${identifier}' is a reserved word in JavaScript and cannot be used here`
diff --git a/src/compiler/parse/read/context.ts b/src/compiler/parse/read/context.ts
index 0db0c676a3..fe666467f8 100644
--- a/src/compiler/parse/read/context.ts
+++ b/src/compiler/parse/read/context.ts
@@ -1,4 +1,5 @@
 import { Parser } from '../index';
+import { reserved } from '../../utils/names';
 
 interface Identifier {
 	start: number;
@@ -116,8 +117,11 @@ export default function read_context(parser: Parser) {
 				break;
 			}
 
+			// TODO: DRY this out somehow
+			// We don't know whether we want to allow reserved words until we see whether there's a ':' after it
+			// Probably ideally we'd use Acorn to do all of this
 			const start = parser.index;
-			const name = parser.read_identifier();
+			const name = parser.read_identifier(true);
 			const key: Identifier = {
 				start,
 				end: parser.index,
@@ -126,9 +130,19 @@ export default function read_context(parser: Parser) {
 			};
 			parser.allow_whitespace();
 
-			const value = parser.eat(':')
-				? (parser.allow_whitespace(), read_context(parser))
-				: key;
+			let value: Context;
+			if (parser.eat(':')) {
+				parser.allow_whitespace();
+				value = read_context(parser);
+			} else {
+				if (reserved.has(name)) {
+					parser.error({
+						code: `unexpected-reserved-word`,
+						message: `'${name}' is a reserved word in JavaScript and cannot be used here`
+					}, start);
+				}
+				value = key;
+			}
 
 			const property: Property = {
 				start,
diff --git a/src/compiler/parse/read/expression.ts b/src/compiler/parse/read/expression.ts
index c8e955b719..f0f4e15c7a 100644
--- a/src/compiler/parse/read/expression.ts
+++ b/src/compiler/parse/read/expression.ts
@@ -1,37 +1,9 @@
 import { parse_expression_at } from '../acorn';
 import { Parser } from '../index';
-import { Identifier, Node, SimpleLiteral } from 'estree';
+import { Node } from 'estree';
 import { whitespace } from '../../utils/patterns';
 
-const literals = new Map([['true', true], ['false', false], ['null', null]]);
-
 export default function read_expression(parser: Parser): Node {
-	const start = parser.index;
-
-	const name = parser.read_until(/\s*}/);
-	if (name && /^[a-z]+$/.test(name)) {
-		const end = start + name.length;
-
-		if (literals.has(name)) {
-			return {
-				type: 'Literal',
-				start,
-				end,
-				value: literals.get(name),
-				raw: name,
-			} as SimpleLiteral;
-		}
-
-		return {
-			type: 'Identifier',
-			start,
-			end: start + name.length,
-			name,
-		} as Identifier;
-	}
-
-	parser.index = start;
-
 	try {
 		const node = parse_expression_at(parser.template, parser.index);
 
diff --git a/test/parser/samples/action-with-identifier/output.json b/test/parser/samples/action-with-identifier/output.json
index 435aee4444..9ae0011c52 100644
--- a/test/parser/samples/action-with-identifier/output.json
+++ b/test/parser/samples/action-with-identifier/output.json
@@ -20,6 +20,16 @@
 							"type": "Identifier",
 							"start": 20,
 							"end": 27,
+							"loc": {
+								"start": {
+									"line": 1,
+									"column": 20
+								},
+								"end": {
+									"line": 1,
+									"column": 27
+								}
+							},
 							"name": "message"
 						}
 					}
diff --git a/test/parser/samples/attribute-dynamic-boolean/output.json b/test/parser/samples/attribute-dynamic-boolean/output.json
index 478144152a..ab6b3927ce 100644
--- a/test/parser/samples/attribute-dynamic-boolean/output.json
+++ b/test/parser/samples/attribute-dynamic-boolean/output.json
@@ -24,6 +24,16 @@
 									"type": "Identifier",
 									"start": 20,
 									"end": 28,
+									"loc": {
+										"start": {
+											"line": 1,
+											"column": 20
+										},
+										"end": {
+											"line": 1,
+											"column": 28
+										}
+									},
 									"name": "readonly"
 								}
 							}
diff --git a/test/parser/samples/attribute-dynamic-reserved/input.svelte b/test/parser/samples/attribute-dynamic-reserved/input.svelte
deleted file mode 100644
index d973a9dea0..0000000000
--- a/test/parser/samples/attribute-dynamic-reserved/input.svelte
+++ /dev/null
@@ -1 +0,0 @@
-<div class={class}></div>
\ No newline at end of file
diff --git a/test/parser/samples/attribute-dynamic-reserved/output.json b/test/parser/samples/attribute-dynamic-reserved/output.json
deleted file mode 100644
index 22be3c9087..0000000000
--- a/test/parser/samples/attribute-dynamic-reserved/output.json
+++ /dev/null
@@ -1,37 +0,0 @@
-{
-	"html": {
-		"start": 0,
-		"end": 25,
-		"type": "Fragment",
-		"children": [
-			{
-				"start": 0,
-				"end": 25,
-				"type": "Element",
-				"name": "div",
-				"attributes": [
-					{
-						"start": 5,
-						"end": 18,
-						"type": "Attribute",
-						"name": "class",
-						"value": [
-							{
-								"start": 11,
-								"end": 18,
-								"type": "MustacheTag",
-								"expression": {
-									"type": "Identifier",
-									"start": 12,
-									"end": 17,
-									"name": "class"
-								}
-							}
-						]
-					}
-				],
-				"children": []
-			}
-		]
-	}
-}
\ No newline at end of file
diff --git a/test/parser/samples/attribute-dynamic/output.json b/test/parser/samples/attribute-dynamic/output.json
index a48f376876..28b9da1dea 100644
--- a/test/parser/samples/attribute-dynamic/output.json
+++ b/test/parser/samples/attribute-dynamic/output.json
@@ -31,6 +31,16 @@
 									"type": "Identifier",
 									"start": 20,
 									"end": 25,
+									"loc": {
+										"start": {
+											"line": 1,
+											"column": 20
+										},
+										"end": {
+											"line": 1,
+											"column": 25
+										}
+									},
 									"name": "color"
 								}
 							},
@@ -53,6 +63,16 @@
 							"type": "Identifier",
 							"start": 30,
 							"end": 35,
+							"loc": {
+								"start": {
+									"line": 1,
+									"column": 30
+								},
+								"end": {
+									"line": 1,
+									"column": 35
+								}
+							},
 							"name": "color"
 						}
 					}
diff --git a/test/parser/samples/attribute-with-whitespace/output.json b/test/parser/samples/attribute-with-whitespace/output.json
index 11d5aa5e06..edf05ca32e 100644
--- a/test/parser/samples/attribute-with-whitespace/output.json
+++ b/test/parser/samples/attribute-with-whitespace/output.json
@@ -20,6 +20,16 @@
 							"type": "Identifier",
 							"start": 19,
 							"end": 22,
+							"loc": {
+								"start": {
+									"line": 1,
+									"column": 19
+								},
+								"end": {
+									"line": 1,
+									"column": 22
+								}
+							},
 							"name": "foo"
 						}
 					}
diff --git a/test/parser/samples/binding/output.json b/test/parser/samples/binding/output.json
index 558215f41a..c980b7f3eb 100644
--- a/test/parser/samples/binding/output.json
+++ b/test/parser/samples/binding/output.json
@@ -27,6 +27,16 @@
 							"type": "Identifier",
 							"start": 50,
 							"end": 54,
+							"loc": {
+								"start": {
+									"line": 5,
+									"column": 19
+								},
+								"end": {
+									"line": 5,
+									"column": 23
+								}
+							},
 							"name": "name"
 						}
 					}
diff --git a/test/parser/samples/each-block-destructured/output.json b/test/parser/samples/each-block-destructured/output.json
index bafde1324d..425c609a2c 100644
--- a/test/parser/samples/each-block-destructured/output.json
+++ b/test/parser/samples/each-block-destructured/output.json
@@ -40,6 +40,16 @@
 									"type": "Identifier",
 									"start": 46,
 									"end": 49,
+									"loc": {
+										"start": {
+											"line": 2,
+											"column": 5
+										},
+										"end": {
+											"line": 2,
+											"column": 8
+										}
+									},
 									"name": "key"
 								}
 							},
@@ -58,6 +68,16 @@
 									"type": "Identifier",
 									"start": 53,
 									"end": 58,
+									"loc": {
+										"start": {
+											"line": 2,
+											"column": 12
+										},
+										"end": {
+											"line": 2,
+											"column": 17
+										}
+									},
 									"name": "value"
 								}
 							}
diff --git a/test/parser/samples/each-block-else/output.json b/test/parser/samples/each-block-else/output.json
index 19b5af19b4..2720ce5292 100644
--- a/test/parser/samples/each-block-else/output.json
+++ b/test/parser/samples/each-block-else/output.json
@@ -40,6 +40,16 @@
 									"type": "Identifier",
 									"start": 31,
 									"end": 37,
+									"loc": {
+										"start": {
+											"line": 2,
+											"column": 5
+										},
+										"end": {
+											"line": 2,
+											"column": 11
+										}
+									},
 									"name": "animal"
 								}
 							}
diff --git a/test/parser/samples/each-block-indexed/output.json b/test/parser/samples/each-block-indexed/output.json
index 68a12ea31c..50f2000a36 100644
--- a/test/parser/samples/each-block-indexed/output.json
+++ b/test/parser/samples/each-block-indexed/output.json
@@ -40,6 +40,16 @@
 									"type": "Identifier",
 									"start": 34,
 									"end": 35,
+									"loc": {
+										"start": {
+											"line": 2,
+											"column": 5
+										},
+										"end": {
+											"line": 2,
+											"column": 6
+										}
+									},
 									"name": "i"
 								}
 							},
@@ -58,6 +68,16 @@
 									"type": "Identifier",
 									"start": 39,
 									"end": 45,
+									"loc": {
+										"start": {
+											"line": 2,
+											"column": 10
+										},
+										"end": {
+											"line": 2,
+											"column": 16
+										}
+									},
 									"name": "animal"
 								}
 							}
diff --git a/test/parser/samples/each-block-keyed/output.json b/test/parser/samples/each-block-keyed/output.json
index 61b5442c0d..7dc8681453 100644
--- a/test/parser/samples/each-block-keyed/output.json
+++ b/test/parser/samples/each-block-keyed/output.json
@@ -40,6 +40,16 @@
 									"type": "Identifier",
 									"start": 37,
 									"end": 41,
+									"loc": {
+										"start": {
+											"line": 2,
+											"column": 5
+										},
+										"end": {
+											"line": 2,
+											"column": 9
+										}
+									},
 									"name": "todo"
 								}
 							}
diff --git a/test/parser/samples/each-block/output.json b/test/parser/samples/each-block/output.json
index 38bc7e1d04..6594fb50a6 100644
--- a/test/parser/samples/each-block/output.json
+++ b/test/parser/samples/each-block/output.json
@@ -40,6 +40,16 @@
 									"type": "Identifier",
 									"start": 31,
 									"end": 37,
+									"loc": {
+										"start": {
+											"line": 2,
+											"column": 5
+										},
+										"end": {
+											"line": 2,
+											"column": 11
+										}
+									},
 									"name": "animal"
 								}
 							}
diff --git a/test/parser/samples/element-with-mustache/output.json b/test/parser/samples/element-with-mustache/output.json
index f7c2e9936b..049e373100 100644
--- a/test/parser/samples/element-with-mustache/output.json
+++ b/test/parser/samples/element-with-mustache/output.json
@@ -26,6 +26,16 @@
 							"type": "Identifier",
 							"start": 11,
 							"end": 15,
+							"loc": {
+								"start": {
+									"line": 1,
+									"column": 11
+								},
+								"end": {
+									"line": 1,
+									"column": 15
+								}
+							},
 							"name": "name"
 						}
 					},
diff --git a/test/parser/samples/event-handler/output.json b/test/parser/samples/event-handler/output.json
index 44bb83de7d..95db9998f4 100644
--- a/test/parser/samples/event-handler/output.json
+++ b/test/parser/samples/event-handler/output.json
@@ -128,6 +128,16 @@
 					"type": "Identifier",
 					"start": 68,
 					"end": 75,
+					"loc": {
+						"start": {
+							"line": 3,
+							"column": 5
+						},
+						"end": {
+							"line": 3,
+							"column": 12
+						}
+					},
 					"name": "visible"
 				},
 				"children": [
diff --git a/test/parser/samples/if-block-else/output.json b/test/parser/samples/if-block-else/output.json
index 8b22cfa26b..1f2cff3ff9 100644
--- a/test/parser/samples/if-block-else/output.json
+++ b/test/parser/samples/if-block-else/output.json
@@ -12,6 +12,16 @@
 					"type": "Identifier",
 					"start": 5,
 					"end": 8,
+					"loc": {
+						"start": {
+							"line": 1,
+							"column": 5
+						},
+						"end": {
+							"line": 1,
+							"column": 8
+						}
+					},
 					"name": "foo"
 				},
 				"children": [
diff --git a/test/parser/samples/if-block/output.json b/test/parser/samples/if-block/output.json
index 1714bb7141..ef895a366a 100644
--- a/test/parser/samples/if-block/output.json
+++ b/test/parser/samples/if-block/output.json
@@ -12,6 +12,16 @@
 					"type": "Identifier",
 					"start": 5,
 					"end": 8,
+					"loc": {
+						"start": {
+							"line": 1,
+							"column": 5
+						},
+						"end": {
+							"line": 1,
+							"column": 8
+						}
+					},
 					"name": "foo"
 				},
 				"children": [
diff --git a/test/parser/samples/implicitly-closed-li-block/output.json b/test/parser/samples/implicitly-closed-li-block/output.json
index 4a75a34223..767f64053c 100644
--- a/test/parser/samples/implicitly-closed-li-block/output.json
+++ b/test/parser/samples/implicitly-closed-li-block/output.json
@@ -40,6 +40,16 @@
 									"type": "Literal",
 									"start": 18,
 									"end": 22,
+									"loc": {
+										"start": {
+											"line": 3,
+											"column": 6
+										},
+										"end": {
+											"line": 3,
+											"column": 10
+										}
+									},
 									"value": true,
 									"raw": "true"
 								},
diff --git a/test/parser/samples/refs/output.json b/test/parser/samples/refs/output.json
index 72a3d7689c..fb94ffd701 100644
--- a/test/parser/samples/refs/output.json
+++ b/test/parser/samples/refs/output.json
@@ -27,6 +27,16 @@
 							"type": "Identifier",
 							"start": 49,
 							"end": 52,
+							"loc": {
+								"start": {
+									"line": 5,
+									"column": 19
+								},
+								"end": {
+									"line": 5,
+									"column": 22
+								}
+							},
 							"name": "foo"
 						}
 					}
diff --git a/test/parser/samples/script-comment-trailing-multiline/output.json b/test/parser/samples/script-comment-trailing-multiline/output.json
index be83eeea8b..184a29978d 100644
--- a/test/parser/samples/script-comment-trailing-multiline/output.json
+++ b/test/parser/samples/script-comment-trailing-multiline/output.json
@@ -33,6 +33,16 @@
 							"type": "Identifier",
 							"start": 90,
 							"end": 94,
+							"loc": {
+								"start": {
+									"line": 9,
+									"column": 11
+								},
+								"end": {
+									"line": 9,
+									"column": 15
+								}
+							},
 							"name": "name"
 						}
 					},
diff --git a/test/parser/samples/script-comment-trailing/output.json b/test/parser/samples/script-comment-trailing/output.json
index a2bc00bc00..2aca23f667 100644
--- a/test/parser/samples/script-comment-trailing/output.json
+++ b/test/parser/samples/script-comment-trailing/output.json
@@ -33,6 +33,16 @@
 							"type": "Identifier",
 							"start": 79,
 							"end": 83,
+							"loc": {
+								"start": {
+									"line": 7,
+									"column": 11
+								},
+								"end": {
+									"line": 7,
+									"column": 15
+								}
+							},
 							"name": "name"
 						}
 					},
diff --git a/test/parser/samples/script/output.json b/test/parser/samples/script/output.json
index 00b7073a19..4d0aa9cf36 100644
--- a/test/parser/samples/script/output.json
+++ b/test/parser/samples/script/output.json
@@ -33,6 +33,16 @@
 							"type": "Identifier",
 							"start": 52,
 							"end": 56,
+							"loc": {
+								"start": {
+									"line": 5,
+									"column": 11
+								},
+								"end": {
+									"line": 5,
+									"column": 15
+								}
+							},
 							"name": "name"
 						}
 					},
diff --git a/test/parser/samples/space-between-mustaches/output.json b/test/parser/samples/space-between-mustaches/output.json
index 9a367bd2c1..b89f4d6c83 100644
--- a/test/parser/samples/space-between-mustaches/output.json
+++ b/test/parser/samples/space-between-mustaches/output.json
@@ -26,6 +26,16 @@
 							"type": "Identifier",
 							"start": 5,
 							"end": 6,
+							"loc": {
+								"start": {
+									"line": 1,
+									"column": 5
+								},
+								"end": {
+									"line": 1,
+									"column": 6
+								}
+							},
 							"name": "a"
 						}
 					},
@@ -44,6 +54,16 @@
 							"type": "Identifier",
 							"start": 9,
 							"end": 10,
+							"loc": {
+								"start": {
+									"line": 1,
+									"column": 9
+								},
+								"end": {
+									"line": 1,
+									"column": 10
+								}
+							},
 							"name": "b"
 						}
 					},
@@ -62,6 +82,16 @@
 							"type": "Identifier",
 							"start": 15,
 							"end": 16,
+							"loc": {
+								"start": {
+									"line": 1,
+									"column": 15
+								},
+								"end": {
+									"line": 1,
+									"column": 16
+								}
+							},
 							"name": "c"
 						}
 					},
diff --git a/test/parser/samples/spread/output.json b/test/parser/samples/spread/output.json
index 73a0dc9777..3a5c471905 100644
--- a/test/parser/samples/spread/output.json
+++ b/test/parser/samples/spread/output.json
@@ -18,6 +18,16 @@
 							"type": "Identifier",
 							"start": 9,
 							"end": 14,
+							"loc": {
+								"start": {
+									"line": 1,
+									"column": 9
+								},
+								"end": {
+									"line": 1,
+									"column": 14
+								}
+							},
 							"name": "props"
 						}
 					}
diff --git a/test/parser/samples/textarea-children/output.json b/test/parser/samples/textarea-children/output.json
index 90f31f3caf..919fa33fde 100644
--- a/test/parser/samples/textarea-children/output.json
+++ b/test/parser/samples/textarea-children/output.json
@@ -29,6 +29,16 @@
 									"type": "Identifier",
 									"start": 41,
 									"end": 44,
+									"loc": {
+										"start": {
+											"line": 2,
+											"column": 30
+										},
+										"end": {
+											"line": 2,
+											"column": 33
+										}
+									},
 									"name": "foo"
 								}
 							},
diff --git a/test/parser/samples/whitespace-normal/output.json b/test/parser/samples/whitespace-normal/output.json
index acbae7ae17..61eca1329f 100644
--- a/test/parser/samples/whitespace-normal/output.json
+++ b/test/parser/samples/whitespace-normal/output.json
@@ -33,6 +33,16 @@
 									"type": "Identifier",
 									"start": 19,
 									"end": 23,
+									"loc": {
+										"start": {
+											"line": 1,
+											"column": 19
+										},
+										"end": {
+											"line": 1,
+											"column": 23
+										}
+									},
 									"name": "name"
 								}
 							},
diff --git a/test/parser/samples/yield/input.svelte b/test/parser/samples/yield/input.svelte
deleted file mode 100644
index f5e8aad053..0000000000
--- a/test/parser/samples/yield/input.svelte
+++ /dev/null
@@ -1 +0,0 @@
-{yield}
\ No newline at end of file
diff --git a/test/parser/samples/yield/output.json b/test/parser/samples/yield/output.json
deleted file mode 100644
index b2e4b9430f..0000000000
--- a/test/parser/samples/yield/output.json
+++ /dev/null
@@ -1,20 +0,0 @@
-{
-	"html": {
-		"start": 0,
-		"end": 7,
-		"type": "Fragment",
-		"children": [
-			{
-				"start": 0,
-				"end": 7,
-				"type": "MustacheTag",
-				"expression": {
-					"type": "Identifier",
-					"start": 1,
-					"end": 6,
-					"name": "yield"
-				}
-			}
-		]
-	}
-}
\ No newline at end of file
diff --git a/test/runtime/samples/each-block-destructured-object-reserved-key/_config.js b/test/runtime/samples/each-block-destructured-object-reserved-key/_config.js
new file mode 100644
index 0000000000..c04e984691
--- /dev/null
+++ b/test/runtime/samples/each-block-destructured-object-reserved-key/_config.js
@@ -0,0 +1,5 @@
+export default {
+	html: `
+		<p>bar</p>
+	`
+};
diff --git a/test/runtime/samples/each-block-destructured-object-reserved-key/main.svelte b/test/runtime/samples/each-block-destructured-object-reserved-key/main.svelte
new file mode 100644
index 0000000000..c3e11c3ea1
--- /dev/null
+++ b/test/runtime/samples/each-block-destructured-object-reserved-key/main.svelte
@@ -0,0 +1,7 @@
+<script>
+	const foo = [{ in: 'bar' }];
+</script>
+
+{#each foo as { in: bar }}
+	<p>{bar}</p>
+{/each}
diff --git a/test/validator/samples/each-block-invalid-context-destructured-object/errors.json b/test/validator/samples/each-block-invalid-context-destructured-object/errors.json
new file mode 100644
index 0000000000..085021ff5a
--- /dev/null
+++ b/test/validator/samples/each-block-invalid-context-destructured-object/errors.json
@@ -0,0 +1,15 @@
+[{
+	"code": "unexpected-reserved-word",
+	"message": "'case' is a reserved word in JavaScript and cannot be used here",
+	"start": {
+		"line": 1,
+		"column": 18,
+		"character": 18
+	},
+	"end": {
+		"line": 1,
+		"column": 18,
+		"character": 18
+	},
+	"pos": 18
+}]
diff --git a/test/validator/samples/each-block-invalid-context-destructured-object/input.svelte b/test/validator/samples/each-block-invalid-context-destructured-object/input.svelte
new file mode 100644
index 0000000000..a891f131a0
--- /dev/null
+++ b/test/validator/samples/each-block-invalid-context-destructured-object/input.svelte
@@ -0,0 +1,3 @@
+{#each cases as { case }}
+	{case.title}
+{/each}

From 59a5d4a52c801b3c1b5b5033007ab8fad3fd9257 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Sun, 9 Feb 2020 06:48:22 -0500
Subject: [PATCH 56/82] fix tests

---
 .../no-error-if-before-closing/output.json    | 40 +++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/test/parser/samples/no-error-if-before-closing/output.json b/test/parser/samples/no-error-if-before-closing/output.json
index ad8ccd0f91..251cefc0ca 100644
--- a/test/parser/samples/no-error-if-before-closing/output.json
+++ b/test/parser/samples/no-error-if-before-closing/output.json
@@ -12,6 +12,16 @@
 					"type": "Literal",
 					"start": 5,
 					"end": 9,
+					"loc": {
+						"start": {
+							"line": 1,
+							"column": 5
+						},
+						"end": {
+							"line": 1,
+							"column": 9
+						}
+					},
 					"value": true,
 					"raw": "true"
 				},
@@ -47,6 +57,16 @@
 					"type": "Literal",
 					"start": 40,
 					"end": 44,
+					"loc": {
+						"start": {
+							"line": 6,
+							"column": 5
+						},
+						"end": {
+							"line": 6,
+							"column": 9
+						}
+					},
 					"value": true,
 					"raw": "true"
 				},
@@ -82,6 +102,16 @@
 					"type": "Literal",
 					"start": 75,
 					"end": 79,
+					"loc": {
+						"start": {
+							"line": 11,
+							"column": 8
+						},
+						"end": {
+							"line": 11,
+							"column": 12
+						}
+					},
 					"value": true,
 					"raw": "true"
 				},
@@ -155,6 +185,16 @@
 					"type": "Literal",
 					"start": 118,
 					"end": 122,
+					"loc": {
+						"start": {
+							"line": 16,
+							"column": 8
+						},
+						"end": {
+							"line": 16,
+							"column": 12
+						}
+					},
 					"value": true,
 					"raw": "true"
 				},

From 0625fc218bac769a2724454880e03b85202e37bc Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Sun, 9 Feb 2020 09:24:59 -0500
Subject: [PATCH 57/82] fix invalidation in ++foo.bar (#4395)

---
 CHANGELOG.md                                  |  1 +
 src/compiler/compile/render_dom/invalidate.ts |  2 +-
 .../_config.js                                | 31 +++++++++++++++++++
 .../main.svelte                               | 14 +++++++++
 4 files changed, 47 insertions(+), 1 deletion(-)
 create mode 100644 test/runtime/samples/instrumentation-update-expression/_config.js
 create mode 100644 test/runtime/samples/instrumentation-update-expression/main.svelte

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 16e6484ab3..ee84f7b799 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@
 * Permit reserved keywords as destructuring keys in `{#each}` ([#4372](https://github.com/sveltejs/svelte/issues/4372))
 * Disallow reserved keywords in `{expressions}` ([#4372](https://github.com/sveltejs/svelte/issues/4372))
 * Fix code generation error with precedence of arrow functions ([#4384](https://github.com/sveltejs/svelte/issues/4384))
+* Fix invalidation in expressions like `++foo.bar` ([#4393](https://github.com/sveltejs/svelte/issues/4393))
 
 ## 3.18.1
 
diff --git a/src/compiler/compile/render_dom/invalidate.ts b/src/compiler/compile/render_dom/invalidate.ts
index dc28501863..20aff05d1e 100644
--- a/src/compiler/compile/render_dom/invalidate.ts
+++ b/src/compiler/compile/render_dom/invalidate.ts
@@ -49,7 +49,7 @@ export function invalidate(renderer: Renderer, scope: Scope, node: Node, names:
 			const pass_value = (
 				extra_args.length > 0 ||
 				(node.type === 'AssignmentExpression' && node.left.type !== 'Identifier') ||
-				(node.type === 'UpdateExpression' && !node.prefix)
+				(node.type === 'UpdateExpression' && (!node.prefix || node.argument.type !== 'Identifier'))
 			);
 
 			if (pass_value) {
diff --git a/test/runtime/samples/instrumentation-update-expression/_config.js b/test/runtime/samples/instrumentation-update-expression/_config.js
new file mode 100644
index 0000000000..cc33422f6f
--- /dev/null
+++ b/test/runtime/samples/instrumentation-update-expression/_config.js
@@ -0,0 +1,31 @@
+export default {
+	html: `
+		<p>0</p>
+		<button>foo++</button>
+		<button>++foo</button>
+		<p>0</p>
+		<button>bar.bar++</button>
+		<button>++bar.bar</button>
+	`,
+	async test({ assert, target, window }) {
+		const [foo, bar] = target.querySelectorAll('p');
+		const [button1, button2, button3, button4] = target.querySelectorAll('button');
+		const event = new window.MouseEvent('click');
+
+		await button1.dispatchEvent(event);
+		assert.equal(foo.innerHTML, '1');
+		assert.equal(bar.innerHTML, '0');
+
+		await button2.dispatchEvent(event);
+		assert.equal(foo.innerHTML, '2');
+		assert.equal(bar.innerHTML, '0');
+
+		await button3.dispatchEvent(event);
+		assert.equal(foo.innerHTML, '2');
+		assert.equal(bar.innerHTML, '1');
+
+		await button4.dispatchEvent(event);
+		assert.equal(foo.innerHTML, '2');
+		assert.equal(bar.innerHTML, '2');
+	}
+};
diff --git a/test/runtime/samples/instrumentation-update-expression/main.svelte b/test/runtime/samples/instrumentation-update-expression/main.svelte
new file mode 100644
index 0000000000..0672f6330d
--- /dev/null
+++ b/test/runtime/samples/instrumentation-update-expression/main.svelte
@@ -0,0 +1,14 @@
+<script>
+	let foo = 0;
+	let bar = { bar: 0 };
+</script>
+
+<p>{foo}</p>
+
+<button on:click={() => foo++}>foo++</button>
+<button on:click={() => ++foo}>++foo</button>
+
+<p>{bar.bar}</p>
+
+<button on:click={() => bar.bar++}>bar.bar++</button>
+<button on:click={() => ++bar.bar}>++bar.bar</button>

From 7f2ffb29779581ad7ec26044fbf5aeda24523aeb Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Sun, 9 Feb 2020 09:30:57 -0500
Subject: [PATCH 58/82] fix event handlers that are dynamic via reactive
 declarations or stores (#4394)

---
 CHANGELOG.md                                  |  1 +
 src/compiler/compile/nodes/EventHandler.ts    |  7 ----
 .../event-handler-dynamic-2/_config.js        | 33 +++++++++++++++++++
 .../event-handler-dynamic-2/main.svelte       | 20 +++++++++++
 4 files changed, 54 insertions(+), 7 deletions(-)
 create mode 100644 test/runtime/samples/event-handler-dynamic-2/_config.js
 create mode 100644 test/runtime/samples/event-handler-dynamic-2/main.svelte

diff --git a/CHANGELOG.md b/CHANGELOG.md
index ee84f7b799..f6aa7eca07 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@
 * Permit reserved keywords as destructuring keys in `{#each}` ([#4372](https://github.com/sveltejs/svelte/issues/4372))
 * Disallow reserved keywords in `{expressions}` ([#4372](https://github.com/sveltejs/svelte/issues/4372))
 * Fix code generation error with precedence of arrow functions ([#4384](https://github.com/sveltejs/svelte/issues/4384))
+* Fix event handlers that are dynamic via reactive declarations or stores ([#4388](https://github.com/sveltejs/svelte/issues/4388))
 * Fix invalidation in expressions like `++foo.bar` ([#4393](https://github.com/sveltejs/svelte/issues/4393))
 
 ## 3.18.1
diff --git a/src/compiler/compile/nodes/EventHandler.ts b/src/compiler/compile/nodes/EventHandler.ts
index 4242c82394..110542d0b8 100644
--- a/src/compiler/compile/nodes/EventHandler.ts
+++ b/src/compiler/compile/nodes/EventHandler.ts
@@ -53,13 +53,6 @@ export default class EventHandler extends Node {
 		}
 		const node = this.expression.node;
 
-		if (node.type === 'Identifier') {
-			return (
-				this.component.node_for_declaration.get(node.name) &&
-				this.component.var_lookup.get(node.name).reassigned
-			);
-		}
-
 		if (/FunctionExpression/.test(node.type)) {
 			return false;
 		}
diff --git a/test/runtime/samples/event-handler-dynamic-2/_config.js b/test/runtime/samples/event-handler-dynamic-2/_config.js
new file mode 100644
index 0000000000..c996d8f2aa
--- /dev/null
+++ b/test/runtime/samples/event-handler-dynamic-2/_config.js
@@ -0,0 +1,33 @@
+export default {
+	html: `
+		<button>toggle</button>
+		<p>0</p>
+		<button>handler_a</button>
+		<button>handler_b</button>
+	`,
+
+	async test({ assert, target, window }) {
+		const [toggle, handler_a, handler_b] = target.querySelectorAll('button');
+		const p = target.querySelector('p');
+
+		const event = new window.MouseEvent('click');
+
+		await handler_a.dispatchEvent(event);
+		assert.equal(p.innerHTML, '1');
+
+		await toggle.dispatchEvent(event);
+
+		await handler_a.dispatchEvent(event);
+		assert.equal(p.innerHTML, '2');
+
+		await toggle.dispatchEvent(event);
+
+		await handler_b.dispatchEvent(event);
+		assert.equal(p.innerHTML, '1');
+
+		await toggle.dispatchEvent(event);
+
+		await handler_b.dispatchEvent(event);
+		assert.equal(p.innerHTML, '2');
+	},
+};
diff --git a/test/runtime/samples/event-handler-dynamic-2/main.svelte b/test/runtime/samples/event-handler-dynamic-2/main.svelte
new file mode 100644
index 0000000000..1b2041d3b8
--- /dev/null
+++ b/test/runtime/samples/event-handler-dynamic-2/main.svelte
@@ -0,0 +1,20 @@
+<script>
+	import { writable } from 'svelte/store';
+
+	let number = 0;
+	const handler_1 = () => number = 1;
+	const handler_2 = () => number = 2;
+
+	let flag = true;
+
+	$: handler_a = flag ? handler_1 : handler_2;
+	const handler_b = writable();
+	$: handler_b.set(flag ? handler_1 : handler_2);
+</script>
+
+<button on:click={() => flag = !flag}>toggle</button>
+
+<p>{number}</p>
+
+<button on:click={handler_a}>handler_a</button>
+<button on:click={$handler_b}>handler_b</button>

From c3232826d4690bcf9fea780bdb0b14a56e87c20c Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Sun, 9 Feb 2020 09:32:11 -0500
Subject: [PATCH 59/82] -> v3.18.2

---
 CHANGELOG.md      | 2 +-
 package-lock.json | 2 +-
 package.json      | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index f6aa7eca07..c94c24dd65 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,6 @@
 # Svelte changelog
 
-## Unreleased
+## 3.18.2
 
 * Fix binding to module-level variables ([#4086](https://github.com/sveltejs/svelte/issues/4086))
 * Improve parsing error messages when there is a pending unclosed tag ([#4131](https://github.com/sveltejs/svelte/issues/4131))
diff --git a/package-lock.json b/package-lock.json
index 73f49c08e8..8f0b7469f8 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "svelte",
-  "version": "3.18.1",
+  "version": "3.18.2",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
diff --git a/package.json b/package.json
index 4f7acb0fd7..6000e9d1c4 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "svelte",
-  "version": "3.18.1",
+  "version": "3.18.2",
   "description": "Cybernetically enhanced web apps",
   "module": "index.mjs",
   "main": "index",

From b6d80f485af9b2e383044efe3466e684c99620af Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Tue, 11 Feb 2020 21:01:30 -0500
Subject: [PATCH 60/82] fix indirect bindings on elements with spreads (#4398)

---
 CHANGELOG.md                                  |  4 ++
 .../render_dom/wrappers/Element/Attribute.ts  | 19 +++++---
 .../render_dom/wrappers/Element/index.ts      |  8 ++--
 src/runtime/internal/dom.ts                   |  2 +-
 .../binding-indirect-spread/_config.js        | 44 +++++++++++++++++++
 .../binding-indirect-spread/main.svelte       | 12 +++++
 6 files changed, 77 insertions(+), 12 deletions(-)
 create mode 100644 test/runtime/samples/binding-indirect-spread/_config.js
 create mode 100644 test/runtime/samples/binding-indirect-spread/main.svelte

diff --git a/CHANGELOG.md b/CHANGELOG.md
index c94c24dd65..74b16cc16f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Svelte changelog
 
+## Unreleased
+
+* Fix indirect bindings involving elements with spreads ([#3680](https://github.com/sveltejs/svelte/issues/3680))
+
 ## 3.18.2
 
 * Fix binding to module-level variables ([#4086](https://github.com/sveltejs/svelte/issues/4086))
diff --git a/src/compiler/compile/render_dom/wrappers/Element/Attribute.ts b/src/compiler/compile/render_dom/wrappers/Element/Attribute.ts
index ecddaaebaa..85f252f57e 100644
--- a/src/compiler/compile/render_dom/wrappers/Element/Attribute.ts
+++ b/src/compiler/compile/render_dom/wrappers/Element/Attribute.ts
@@ -39,20 +39,25 @@ export default class AttributeWrapper {
 		}
 	}
 
-	render(block: Block) {
+	is_indirectly_bound_value() {
 		const element = this.parent;
 		const name = fix_attribute_casing(this.node.name);
-
-		const metadata = this.get_metadata();
-
-		const is_indirectly_bound_value =
-			name === 'value' &&
+		return name === 'value' &&
 			(element.node.name === 'option' || // TODO check it's actually bound
 				(element.node.name === 'input' &&
-					element.node.bindings.find(
+					element.node.bindings.some(
 						(binding) =>
 							/checked|group/.test(binding.name)
 					)));
+	}
+
+	render(block: Block) {
+		const element = this.parent;
+		const name = fix_attribute_casing(this.node.name);
+
+		const metadata = this.get_metadata();
+
+		const is_indirectly_bound_value = this.is_indirectly_bound_value();
 
 		const property_name = is_indirectly_bound_value
 			? '__value'
diff --git a/src/compiler/compile/render_dom/wrappers/Element/index.ts b/src/compiler/compile/render_dom/wrappers/Element/index.ts
index 8894308fdf..9291f329b6 100644
--- a/src/compiler/compile/render_dom/wrappers/Element/index.ts
+++ b/src/compiler/compile/render_dom/wrappers/Element/index.ts
@@ -679,10 +679,10 @@ export default class ElementWrapper extends Wrapper {
 					updates.push(condition ? x`${condition} && ${snippet}` : snippet);
 				} else {
 					const metadata = attr.get_metadata();
-					const snippet = x`{ ${
-						(metadata && metadata.property_name) ||
-						fix_attribute_casing(attr.node.name)
-					}: ${attr.get_value(block)} }`;
+					const name = attr.is_indirectly_bound_value()
+						? '__value'
+						: (metadata && metadata.property_name) || fix_attribute_casing(attr.node.name);
+					const snippet = x`{ ${name}: ${attr.get_value(block)} }`;
 					initial_props.push(snippet);
 
 					updates.push(condition ? x`${condition} && ${snippet}` : snippet);
diff --git a/src/runtime/internal/dom.ts b/src/runtime/internal/dom.ts
index 5a165136ce..9ab9a4395f 100644
--- a/src/runtime/internal/dom.ts
+++ b/src/runtime/internal/dom.ts
@@ -98,7 +98,7 @@ export function set_attributes(node: Element & ElementCSSInlineStyle, attributes
 			node.removeAttribute(key);
 		} else if (key === 'style') {
 			node.style.cssText = attributes[key];
-		} else if (descriptors[key] && descriptors[key].set) {
+		} else if (key === '__value' || descriptors[key] && descriptors[key].set) {
 			node[key] = attributes[key];
 		} else {
 			attr(node, key, attributes[key]);
diff --git a/test/runtime/samples/binding-indirect-spread/_config.js b/test/runtime/samples/binding-indirect-spread/_config.js
new file mode 100644
index 0000000000..1f24fcdbcb
--- /dev/null
+++ b/test/runtime/samples/binding-indirect-spread/_config.js
@@ -0,0 +1,44 @@
+export default {
+	skip_if_ssr: true,
+	async test({ assert, component, target, window }) {
+		const event = new window.MouseEvent('click');
+
+		const [radio1, radio2, radio3] = target.querySelectorAll('input[type=radio]');
+
+		assert.ok(!radio1.checked);
+		assert.ok(radio2.checked);
+		assert.ok(!radio3.checked);
+
+		component.radio = 'radio1';
+
+		assert.ok(radio1.checked);
+		assert.ok(!radio2.checked);
+		assert.ok(!radio3.checked);
+
+		await radio3.dispatchEvent(event);
+
+		assert.equal(component.radio, 'radio3');
+		assert.ok(!radio1.checked);
+		assert.ok(!radio2.checked);
+		assert.ok(radio3.checked);
+
+		const [check1, check2, check3] = target.querySelectorAll('input[type=checkbox]');
+
+		assert.ok(!check1.checked);
+		assert.ok(check2.checked);
+		assert.ok(!check3.checked);
+
+		component.check = ['check1', 'check2'];
+
+		assert.ok(check1.checked);
+		assert.ok(check2.checked);
+		assert.ok(!check3.checked);
+
+		await check3.dispatchEvent(event);
+
+		assert.deepEqual(component.check, ['check1', 'check2', 'check3']);
+		assert.ok(check1.checked);
+		assert.ok(check2.checked);
+		assert.ok(check3.checked);
+	}
+};
diff --git a/test/runtime/samples/binding-indirect-spread/main.svelte b/test/runtime/samples/binding-indirect-spread/main.svelte
new file mode 100644
index 0000000000..43129b08b7
--- /dev/null
+++ b/test/runtime/samples/binding-indirect-spread/main.svelte
@@ -0,0 +1,12 @@
+<script>
+	export let radio = 'radio2';
+	export let check = ['check2'];
+</script>
+
+<input type='radio' bind:group={radio} value='radio1' {...{}}>
+<input type='radio' bind:group={radio} value='radio2' {...{}}>
+<input type='radio' bind:group={radio} value='radio3' {...{}}>
+
+<input type='checkbox' bind:group={check} value='check1' {...{}}>
+<input type='checkbox' bind:group={check} value='check2' {...{}}>
+<input type='checkbox' bind:group={check} value='check3' {...{}}>

From 7fdae5f8a85cb8bec2ea6ff13cc8956cb3256fad Mon Sep 17 00:00:00 2001
From: PKlknr <60601481+PKlknr@users.noreply.github.com>
Date: Wed, 12 Feb 2020 14:45:06 +0100
Subject: [PATCH 61/82] docs: add await in front of preprocess examples (#4404)

---
 site/content/docs/04-compile-time.md | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/site/content/docs/04-compile-time.md b/site/content/docs/04-compile-time.md
index c46cef117d..0cb2ac3caf 100644
--- a/site/content/docs/04-compile-time.md
+++ b/site/content/docs/04-compile-time.md
@@ -185,7 +185,7 @@ const ast = svelte.parse(source, { filename: 'App.svelte' });
 result: {
 	code: string,
 	dependencies: Array<string>
-} = svelte.preprocess(
+} = await svelte.preprocess(
 	source: string,
 	preprocessors: Array<{
 		markup?: (input: { content: string, filename: string }) => Promise<{
@@ -222,7 +222,7 @@ The `markup` function receives the entire component source text, along with the
 ```js
 const svelte = require('svelte/compiler');
 
-const { code } = svelte.preprocess(source, {
+const { code } = await svelte.preprocess(source, {
 	markup: ({ content, filename }) => {
 		return {
 			code: content.replace(/foo/g, 'bar')
@@ -244,7 +244,7 @@ const svelte = require('svelte/compiler');
 const sass = require('node-sass');
 const { dirname } = require('path');
 
-const { code, dependencies } = svelte.preprocess(source, {
+const { code, dependencies } = await svelte.preprocess(source, {
 	style: async ({ content, attributes, filename }) => {
 		// only process <style lang="sass">
 		if (attributes.lang !== 'sass') return;
@@ -277,7 +277,7 @@ Multiple preprocessors can be used together. The output of the first becomes the
 ```js
 const svelte = require('svelte/compiler');
 
-const { code } = svelte.preprocess(source, [
+const { code } = await svelte.preprocess(source, [
 	{
 		markup: () => {
 			console.log('this runs first');

From 6250046c052eb360e51b272c55870cff71f41a70 Mon Sep 17 00:00:00 2001
From: Tan Li Hau <tanhauhau@users.noreply.github.com>
Date: Sun, 16 Feb 2020 00:57:34 +0800
Subject: [PATCH 62/82] perform dirty check before updating keyed each blocks
 (#4413)

---
 CHANGELOG.md                                  |  1 +
 .../compile/render_dom/wrappers/EachBlock.ts  | 27 ++++++++++++-------
 .../each-block-keyed-animated/expected.js     | 10 ++++---
 test/js/samples/each-block-keyed/expected.js  |  6 +++--
 .../component-binding-blowback-c/main.svelte  |  4 +--
 .../each-block-keyed-dynamic-2/_config.js     | 23 ++++++++++++++++
 .../each-block-keyed-dynamic-2/main.svelte    | 20 ++++++++++++++
 7 files changed, 74 insertions(+), 17 deletions(-)
 create mode 100644 test/runtime/samples/each-block-keyed-dynamic-2/_config.js
 create mode 100644 test/runtime/samples/each-block-keyed-dynamic-2/main.svelte

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 74b16cc16f..406f2a591a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@
 ## Unreleased
 
 * Fix indirect bindings involving elements with spreads ([#3680](https://github.com/sveltejs/svelte/issues/3680))
+* Fix unneeded updating of keyed each blocks ([#4373](https://github.com/sveltejs/svelte/issues/4373))
 
 ## 3.18.2
 
diff --git a/src/compiler/compile/render_dom/wrappers/EachBlock.ts b/src/compiler/compile/render_dom/wrappers/EachBlock.ts
index 639a8831bd..8f8fe29564 100644
--- a/src/compiler/compile/render_dom/wrappers/EachBlock.ts
+++ b/src/compiler/compile/render_dom/wrappers/EachBlock.ts
@@ -412,16 +412,25 @@ export default class EachBlockWrapper extends Wrapper {
 				? `@outro_and_destroy_block`
 				: `@destroy_block`;
 
-		block.chunks.update.push(b`
-			const ${this.vars.each_block_value} = ${snippet};
+		const all_dependencies = new Set(this.block.dependencies); // TODO should be dynamic deps only
+		this.node.expression.dynamic_dependencies().forEach((dependency: string) => {
+			all_dependencies.add(dependency);
+		});
 
-			${this.block.has_outros && b`@group_outros();`}
-			${this.node.has_animation && b`for (let #i = 0; #i < ${view_length}; #i += 1) ${iterations}[#i].r();`}
-			${this.renderer.options.dev && b`@validate_each_keys(#ctx, ${this.vars.each_block_value}, ${this.vars.get_each_context}, ${get_key});`}
-			${iterations} = @update_keyed_each(${iterations}, #dirty, ${get_key}, ${dynamic ? 1 : 0}, #ctx, ${this.vars.each_block_value}, ${lookup}, ${update_mount_node}, ${destroy}, ${create_each_block}, ${update_anchor_node}, ${this.vars.get_each_context});
-			${this.node.has_animation && b`for (let #i = 0; #i < ${view_length}; #i += 1) ${iterations}[#i].a();`}
-			${this.block.has_outros && b`@check_outros();`}
-		`);
+		if (all_dependencies.size) {
+			block.chunks.update.push(b`
+				if (${block.renderer.dirty(Array.from(all_dependencies))}) {
+					const ${this.vars.each_block_value} = ${snippet};
+
+					${this.block.has_outros && b`@group_outros();`}
+					${this.node.has_animation && b`for (let #i = 0; #i < ${view_length}; #i += 1) ${iterations}[#i].r();`}
+					${this.renderer.options.dev && b`@validate_each_keys(#ctx, ${this.vars.each_block_value}, ${this.vars.get_each_context}, ${get_key});`}
+					${iterations} = @update_keyed_each(${iterations}, #dirty, ${get_key}, ${dynamic ? 1 : 0}, #ctx, ${this.vars.each_block_value}, ${lookup}, ${update_mount_node}, ${destroy}, ${create_each_block}, ${update_anchor_node}, ${this.vars.get_each_context});
+					${this.node.has_animation && b`for (let #i = 0; #i < ${view_length}; #i += 1) ${iterations}[#i].a();`}
+					${this.block.has_outros && b`@check_outros();`}
+				}
+			`);
+		}
 
 		if (this.block.has_outros) {
 			block.chunks.outro.push(b`
diff --git a/test/js/samples/each-block-keyed-animated/expected.js b/test/js/samples/each-block-keyed-animated/expected.js
index 3b697d6860..7fb81c27a2 100644
--- a/test/js/samples/each-block-keyed-animated/expected.js
+++ b/test/js/samples/each-block-keyed-animated/expected.js
@@ -92,10 +92,12 @@ function create_fragment(ctx) {
 			insert(target, each_1_anchor, anchor);
 		},
 		p(ctx, [dirty]) {
-			const each_value = /*things*/ ctx[0];
-			for (let i = 0; i < each_blocks.length; i += 1) each_blocks[i].r();
-			each_blocks = update_keyed_each(each_blocks, dirty, get_key, 1, ctx, each_value, each_1_lookup, each_1_anchor.parentNode, fix_and_destroy_block, create_each_block, each_1_anchor, get_each_context);
-			for (let i = 0; i < each_blocks.length; i += 1) each_blocks[i].a();
+			if (dirty & /*things*/ 1) {
+				const each_value = /*things*/ ctx[0];
+				for (let i = 0; i < each_blocks.length; i += 1) each_blocks[i].r();
+				each_blocks = update_keyed_each(each_blocks, dirty, get_key, 1, ctx, each_value, each_1_lookup, each_1_anchor.parentNode, fix_and_destroy_block, create_each_block, each_1_anchor, get_each_context);
+				for (let i = 0; i < each_blocks.length; i += 1) each_blocks[i].a();
+			}
 		},
 		i: noop,
 		o: noop,
diff --git a/test/js/samples/each-block-keyed/expected.js b/test/js/samples/each-block-keyed/expected.js
index 1cd9a31ece..ad8c074e99 100644
--- a/test/js/samples/each-block-keyed/expected.js
+++ b/test/js/samples/each-block-keyed/expected.js
@@ -77,8 +77,10 @@ function create_fragment(ctx) {
 			insert(target, each_1_anchor, anchor);
 		},
 		p(ctx, [dirty]) {
-			const each_value = /*things*/ ctx[0];
-			each_blocks = update_keyed_each(each_blocks, dirty, get_key, 1, ctx, each_value, each_1_lookup, each_1_anchor.parentNode, destroy_block, create_each_block, each_1_anchor, get_each_context);
+			if (dirty & /*things*/ 1) {
+				const each_value = /*things*/ ctx[0];
+				each_blocks = update_keyed_each(each_blocks, dirty, get_key, 1, ctx, each_value, each_1_lookup, each_1_anchor.parentNode, destroy_block, create_each_block, each_1_anchor, get_each_context);
+			}
 		},
 		i: noop,
 		o: noop,
diff --git a/test/runtime/samples/component-binding-blowback-c/main.svelte b/test/runtime/samples/component-binding-blowback-c/main.svelte
index 4876af13a8..75552bf358 100644
--- a/test/runtime/samples/component-binding-blowback-c/main.svelte
+++ b/test/runtime/samples/component-binding-blowback-c/main.svelte
@@ -4,7 +4,7 @@
 	export let count;
 	export let idToValue = Object.create(null);
 
-	function ids() {
+	function ids(count) {
 		return new Array(count)
 			.fill(null)
 			.map((_, i) => ({ id: 'id-' + i}))
@@ -15,7 +15,7 @@
 <input type='number' bind:value={count}>
 
 <ol>
-	{#each ids() as object (object.id)}
+	{#each ids(count) as object (object.id)}
 		<Nested bind:value={idToValue[object.id]} id={object.id}>
 			{object.id}: value is {idToValue[object.id]}
 		</Nested>
diff --git a/test/runtime/samples/each-block-keyed-dynamic-2/_config.js b/test/runtime/samples/each-block-keyed-dynamic-2/_config.js
new file mode 100644
index 0000000000..7eba75a5ff
--- /dev/null
+++ b/test/runtime/samples/each-block-keyed-dynamic-2/_config.js
@@ -0,0 +1,23 @@
+export default {
+	html: `
+	<button>Click Me</button>
+	0
+	<ul></ul>
+	`,
+
+	async test({ assert, component, target, window }) {
+		const button = target.querySelector("button");
+
+		const event = new window.MouseEvent("click");
+		await button.dispatchEvent(event);
+
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+			<button>Click Me</button>
+			1
+			<ul></ul>
+		`
+		);
+	}
+};
diff --git a/test/runtime/samples/each-block-keyed-dynamic-2/main.svelte b/test/runtime/samples/each-block-keyed-dynamic-2/main.svelte
new file mode 100644
index 0000000000..ab455a585e
--- /dev/null
+++ b/test/runtime/samples/each-block-keyed-dynamic-2/main.svelte
@@ -0,0 +1,20 @@
+<script>
+	let num = 0;
+	let cards = [];
+	
+	function click() {
+		// updating cards via push should have no effect to the ul,
+		// since its being mutated instead of reassigned
+		cards.push(num++);
+	}
+</script>
+<button on:click={click}>
+	Click Me
+</button>
+
+{num}
+<ul>
+	{#each cards as c, i (i)}
+		<li>{c}</li>
+  {/each}
+</ul>

From fdc89ebb6287747a0141347ed0f398a796e1ecfd Mon Sep 17 00:00:00 2001
From: Tan Li Hau <tanhauhau@users.noreply.github.com>
Date: Sun, 16 Feb 2020 01:33:33 +0800
Subject: [PATCH 63/82] warn if component is expected to be reactive (#4409)

---
 CHANGELOG.md                                  |  1 +
 .../wrappers/InlineComponent/index.ts         | 17 +++++++
 test/validator/index.js                       |  4 +-
 .../samples/component-dynamic/input.svelte    | 18 +++++++
 .../samples/component-dynamic/options.json    |  3 ++
 .../samples/component-dynamic/warnings.json   | 47 +++++++++++++++++++
 6 files changed, 89 insertions(+), 1 deletion(-)
 create mode 100644 test/validator/samples/component-dynamic/input.svelte
 create mode 100644 test/validator/samples/component-dynamic/options.json
 create mode 100644 test/validator/samples/component-dynamic/warnings.json

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 406f2a591a..759aabfd7d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@
 ## Unreleased
 
 * Fix indirect bindings involving elements with spreads ([#3680](https://github.com/sveltejs/svelte/issues/3680))
+* Warn when using `<Foo/>` and `Foo` is dynamic ([#4331](https://github.com/sveltejs/svelte/issues/4331))
 * Fix unneeded updating of keyed each blocks ([#4373](https://github.com/sveltejs/svelte/issues/4373))
 
 ## 3.18.2
diff --git a/src/compiler/compile/render_dom/wrappers/InlineComponent/index.ts b/src/compiler/compile/render_dom/wrappers/InlineComponent/index.ts
index 631c172576..f1c57ed094 100644
--- a/src/compiler/compile/render_dom/wrappers/InlineComponent/index.ts
+++ b/src/compiler/compile/render_dom/wrappers/InlineComponent/index.ts
@@ -106,11 +106,28 @@ export default class InlineComponentWrapper extends Wrapper {
 		block.add_outro();
 	}
 
+	warn_if_reactive() {
+		const { name } = this.node;
+		const variable = this.renderer.component.var_lookup.get(name);
+		if (!variable) {
+			return;
+		}
+
+		if (variable.reassigned || variable.export_name || variable.is_reactive_dependency) {
+			this.renderer.component.warn(this.node, {
+				code: 'reactive-component',
+				message: `<${name}/> will not be reactive if ${name} changes. Use <svelte:component this={${name}}/> if you want this reactivity.`,
+			});
+		}
+	}
+
 	render(
 		block: Block,
 		parent_node: Identifier,
 		parent_nodes: Identifier
 	) {
+		this.warn_if_reactive();
+
 		const { renderer } = this;
 		const { component } = renderer;
 
diff --git a/test/validator/index.js b/test/validator/index.js
index 8bf0400d7c..9bce5e149b 100644
--- a/test/validator/index.js
+++ b/test/validator/index.js
@@ -20,6 +20,7 @@ describe("validate", () => {
 			const input = fs.readFileSync(`${__dirname}/samples/${dir}/input.svelte`, "utf-8").replace(/\s+$/, "");
 			const expected_warnings = tryToLoadJson(`${__dirname}/samples/${dir}/warnings.json`) || [];
 			const expected_errors = tryToLoadJson(`${__dirname}/samples/${dir}/errors.json`);
+			const options = tryToLoadJson(`${__dirname}/samples/${dir}/options.json`);
 
 			let error;
 
@@ -28,7 +29,8 @@ describe("validate", () => {
 					dev: config.dev,
 					legacy: config.legacy,
 					generate: false,
-					customElement: config.customElement
+					customElement: config.customElement,
+					...options,
 				});
 
 				assert.deepEqual(warnings.map(w => ({
diff --git a/test/validator/samples/component-dynamic/input.svelte b/test/validator/samples/component-dynamic/input.svelte
new file mode 100644
index 0000000000..f591a84fe1
--- /dev/null
+++ b/test/validator/samples/component-dynamic/input.svelte
@@ -0,0 +1,18 @@
+<script>
+	import A from './A.svelte';
+	import B from './B.svelte';
+
+	let Let = A;
+	function update() {
+		Let = B;
+	}
+
+	export let ExportLet = B;
+
+	$: Reactive = random() ? A : B;
+</script>
+
+<Let />
+<ExportLet />
+<Reactive />
+<svelte:component this={Let} />
\ No newline at end of file
diff --git a/test/validator/samples/component-dynamic/options.json b/test/validator/samples/component-dynamic/options.json
new file mode 100644
index 0000000000..3a50892eba
--- /dev/null
+++ b/test/validator/samples/component-dynamic/options.json
@@ -0,0 +1,3 @@
+{
+  "generate": true
+}
\ No newline at end of file
diff --git a/test/validator/samples/component-dynamic/warnings.json b/test/validator/samples/component-dynamic/warnings.json
new file mode 100644
index 0000000000..457ef11a1e
--- /dev/null
+++ b/test/validator/samples/component-dynamic/warnings.json
@@ -0,0 +1,47 @@
+[
+	{
+		"code": "reactive-component",
+    "message": "<Let/> will not be reactive if Let changes. Use <svelte:component this={Let}/> if you want this reactivity.",
+    "pos": 190,
+		"end": {
+			"character": 197,
+			"column": 7,
+			"line": 15
+		},
+		"start": {
+			"character": 190,
+			"column": 0,
+			"line": 15
+		}
+	},
+	{
+    "message": "<ExportLet/> will not be reactive if ExportLet changes. Use <svelte:component this={ExportLet}/> if you want this reactivity.",
+		"code": "reactive-component",
+    "pos": 198,
+		"end": {
+			"character": 211,
+			"column": 13,
+			"line": 16
+		},
+		"start": {
+			"character": 198,
+			"column": 0,
+			"line": 16
+		}
+	},
+	{
+    "message": "<Reactive/> will not be reactive if Reactive changes. Use <svelte:component this={Reactive}/> if you want this reactivity.",
+		"code": "reactive-component",
+    "pos": 212,
+		"end": {
+			"character": 224,
+			"column": 12,
+			"line": 17
+		},
+		"start": {
+			"character": 212,
+			"column": 0,
+			"line": 17
+		}
+	}
+]

From 2b3c2daafb854d04100e0648910083d493bcb1d7 Mon Sep 17 00:00:00 2001
From: Kevin Tewouda <rollandkev@yahoo.fr>
Date: Sat, 15 Feb 2020 18:35:54 +0100
Subject: [PATCH 64/82] blog: svelte-for-new-developers: list commands for
 Windows (#4391)

---
 site/content/blog/2019-04-16-svelte-for-new-developers.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/site/content/blog/2019-04-16-svelte-for-new-developers.md b/site/content/blog/2019-04-16-svelte-for-new-developers.md
index fc8e993e88..796a6c11ab 100644
--- a/site/content/blog/2019-04-16-svelte-for-new-developers.md
+++ b/site/content/blog/2019-04-16-svelte-for-new-developers.md
@@ -18,7 +18,7 @@ You'll be using the *command line*, also known as the terminal. On Windows, you
 
 The command line is a way to interact with your computer (or another computer! but that's a topic for another time) with more power and control than the GUI (graphical user interface) that most people use day-to-day.
 
-Once on the command line, you can navigate the filesystem using `ls` to list the contents of your current directory, and `cd` to change the current directory. For example, if you had a `Development` directory of your projects inside your home directory, you would type
+Once on the command line, you can navigate the filesystem using `ls` (`dir` on Windows) to list the contents of your current directory, and `cd` to change the current directory. For example, if you had a `Development` directory of your projects inside your home directory, you would type
 
 ```bash
 cd Development
@@ -34,7 +34,7 @@ cd svelte-projects
 A full introduction to the command line is out of the scope of this guide, but here are a few more useful commands:
 
 * `cd ..` — navigates to the parent of the current directory
-* `cat my-file.txt` — on Mac/Linux, lists the contents of `my-file.txt`
+* `cat my-file.txt` — on Mac/Linux (`type my-file.txt` on Windows), lists the contents of `my-file.txt`
 * `open .` (or `start .` on Windows) — opens the current directory in Finder or File Explorer
 
 

From ad139bfb630ce00ffd95b7a07c25f901bb6b5a50 Mon Sep 17 00:00:00 2001
From: PKlknr <60601481+PKlknr@users.noreply.github.com>
Date: Tue, 18 Feb 2020 09:31:04 +0100
Subject: [PATCH 65/82] Log warnings in svelte/register when in dev-mode
 (#4365)

---
 register.js | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/register.js b/register.js
index 3278c1cbf5..25f8aa4309 100644
--- a/register.js
+++ b/register.js
@@ -36,7 +36,15 @@ function registerExtension(extension) {
 			format: 'cjs'
 		});
 
-		const { js } = compile(fs.readFileSync(filename, 'utf-8'), options);
+		const { js, warnings } = compile(fs.readFileSync(filename, 'utf-8'), options);
+		
+		if (options.dev) {
+			warnings.forEach(warning => {
+				console.warn(`\nSvelte Warning in ${warning.filename}:`);
+				console.warn(warning.message);
+				console.warn(warning.frame);
+			})
+		}
 
 		return module._compile(js.code, filename);
 	};

From 30b09f31820529eb718fb6c5abb8c3fc15431cd0 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Tue, 18 Feb 2020 03:32:42 -0500
Subject: [PATCH 66/82] update changelog

---
 CHANGELOG.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 759aabfd7d..fb8cada5e5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@
 
 * Fix indirect bindings involving elements with spreads ([#3680](https://github.com/sveltejs/svelte/issues/3680))
 * Warn when using `<Foo/>` and `Foo` is dynamic ([#4331](https://github.com/sveltejs/svelte/issues/4331))
+* Display compilation warnings in `svelte/register` in dev mode ([#4364](https://github.com/sveltejs/svelte/issues/4364))
 * Fix unneeded updating of keyed each blocks ([#4373](https://github.com/sveltejs/svelte/issues/4373))
 
 ## 3.18.2

From 3fbafe33c21184d090710d35a44aabf84744dc50 Mon Sep 17 00:00:00 2001
From: swyx <shawnthe1@gmail.com>
Date: Tue, 18 Feb 2020 01:49:40 -0800
Subject: [PATCH 67/82] implement Dev mode validation of {#each} block argument
 (#4419)

---
 src/compiler/compile/render_dom/wrappers/EachBlock.ts  |  5 +++++
 src/runtime/internal/dev.ts                            | 10 ++++++++++
 test/js/samples/debug-foo-bar-baz-things/expected.js   |  5 ++++-
 test/js/samples/debug-foo/expected.js                  |  5 ++++-
 test/js/samples/debug-no-dependencies/expected.js      |  5 ++++-
 .../dev-warning-each-block-no-sets-maps/_config.js     |  6 ++++++
 .../dev-warning-each-block-no-sets-maps/main.svelte    |  7 +++++++
 .../_config.js                                         |  6 ++++++
 .../main.svelte                                        |  3 +++
 9 files changed, 49 insertions(+), 3 deletions(-)
 create mode 100644 test/runtime/samples/dev-warning-each-block-no-sets-maps/_config.js
 create mode 100644 test/runtime/samples/dev-warning-each-block-no-sets-maps/main.svelte
 create mode 100644 test/runtime/samples/dev-warning-each-block-require-arraylike/_config.js
 create mode 100644 test/runtime/samples/dev-warning-each-block-require-arraylike/main.svelte

diff --git a/src/compiler/compile/render_dom/wrappers/EachBlock.ts b/src/compiler/compile/render_dom/wrappers/EachBlock.ts
index 8f8fe29564..f0dfa5fbcc 100644
--- a/src/compiler/compile/render_dom/wrappers/EachBlock.ts
+++ b/src/compiler/compile/render_dom/wrappers/EachBlock.ts
@@ -204,6 +204,9 @@ export default class EachBlockWrapper extends Wrapper {
 		const snippet = this.node.expression.manipulate(block);
 
 		block.chunks.init.push(b`let ${this.vars.each_block_value} = ${snippet};`);
+		if (this.renderer.options.dev) {
+			block.chunks.init.push(b`@validate_each_argument(${this.vars.each_block_value});`);
+		}
 
 		// TODO which is better — Object.create(array) or array.slice()?
 		renderer.blocks.push(b`
@@ -421,6 +424,7 @@ export default class EachBlockWrapper extends Wrapper {
 			block.chunks.update.push(b`
 				if (${block.renderer.dirty(Array.from(all_dependencies))}) {
 					const ${this.vars.each_block_value} = ${snippet};
+					${this.renderer.options.dev && b`@validate_each_argument(${this.vars.each_block_value});`}
 
 					${this.block.has_outros && b`@group_outros();`}
 					${this.node.has_animation && b`for (let #i = 0; #i < ${view_length}; #i += 1) ${iterations}[#i].r();`}
@@ -572,6 +576,7 @@ export default class EachBlockWrapper extends Wrapper {
 			const update = b`
 				${!this.block.has_update_method && b`const #old_length = ${this.vars.each_block_value}.length;`}
 				${this.vars.each_block_value} = ${snippet};
+				${this.renderer.options.dev && b`@validate_each_argument(${this.vars.each_block_value});`}
 
 				let #i;
 				for (#i = ${start}; #i < ${data_length}; #i += 1) {
diff --git a/src/runtime/internal/dev.ts b/src/runtime/internal/dev.ts
index 1829225ad9..7f4b52eb3b 100644
--- a/src/runtime/internal/dev.ts
+++ b/src/runtime/internal/dev.ts
@@ -79,6 +79,16 @@ export function set_data_dev(text, data) {
 	text.data = data;
 }
 
+export function validate_each_argument(arg) {
+	if (!arg || !('length' in arg)) {
+		let msg = '{#each} only iterates over array-like objects.';
+		if (typeof Symbol === 'function' && arg && Symbol.iterator in arg) {
+			msg += ' You can use a spread to convert this iterable into an array.';
+		}
+		throw new Error(msg);
+	}
+}
+
 
 type Props = Record<string, any>;
 export interface SvelteComponentDev {
diff --git a/test/js/samples/debug-foo-bar-baz-things/expected.js b/test/js/samples/debug-foo-bar-baz-things/expected.js
index fc65c59eda..3209afe8a2 100644
--- a/test/js/samples/debug-foo-bar-baz-things/expected.js
+++ b/test/js/samples/debug-foo-bar-baz-things/expected.js
@@ -13,7 +13,8 @@ import {
 	safe_not_equal,
 	set_data_dev,
 	space,
-	text
+	text,
+	validate_each_argument
 } from "svelte/internal";
 
 const file = undefined;
@@ -88,6 +89,7 @@ function create_fragment(ctx) {
 	let t1;
 	let t2;
 	let each_value = /*things*/ ctx[0];
+	validate_each_argument(each_value);
 	let each_blocks = [];
 
 	for (let i = 0; i < each_value.length; i += 1) {
@@ -122,6 +124,7 @@ function create_fragment(ctx) {
 		p: function update(ctx, [dirty]) {
 			if (dirty & /*things*/ 1) {
 				each_value = /*things*/ ctx[0];
+				validate_each_argument(each_value);
 				let i;
 
 				for (i = 0; i < each_value.length; i += 1) {
diff --git a/test/js/samples/debug-foo/expected.js b/test/js/samples/debug-foo/expected.js
index 710d6b2232..4b08be44d9 100644
--- a/test/js/samples/debug-foo/expected.js
+++ b/test/js/samples/debug-foo/expected.js
@@ -13,7 +13,8 @@ import {
 	safe_not_equal,
 	set_data_dev,
 	space,
-	text
+	text,
+	validate_each_argument
 } from "svelte/internal";
 
 const file = undefined;
@@ -82,6 +83,7 @@ function create_fragment(ctx) {
 	let t1;
 	let t2;
 	let each_value = /*things*/ ctx[0];
+	validate_each_argument(each_value);
 	let each_blocks = [];
 
 	for (let i = 0; i < each_value.length; i += 1) {
@@ -116,6 +118,7 @@ function create_fragment(ctx) {
 		p: function update(ctx, [dirty]) {
 			if (dirty & /*things*/ 1) {
 				each_value = /*things*/ ctx[0];
+				validate_each_argument(each_value);
 				let i;
 
 				for (i = 0; i < each_value.length; i += 1) {
diff --git a/test/js/samples/debug-no-dependencies/expected.js b/test/js/samples/debug-no-dependencies/expected.js
index 054dda7953..9985c814a2 100644
--- a/test/js/samples/debug-no-dependencies/expected.js
+++ b/test/js/samples/debug-no-dependencies/expected.js
@@ -10,7 +10,8 @@ import {
 	noop,
 	safe_not_equal,
 	space,
-	text
+	text,
+	validate_each_argument
 } from "svelte/internal";
 
 const file = undefined;
@@ -64,6 +65,7 @@ function create_each_block(ctx) {
 function create_fragment(ctx) {
 	let each_1_anchor;
 	let each_value = things;
+	validate_each_argument(each_value);
 	let each_blocks = [];
 
 	for (let i = 0; i < each_value.length; i += 1) {
@@ -91,6 +93,7 @@ function create_fragment(ctx) {
 		p: function update(ctx, [dirty]) {
 			if (dirty & /*things*/ 0) {
 				each_value = things;
+				validate_each_argument(each_value);
 				let i;
 
 				for (i = 0; i < each_value.length; i += 1) {
diff --git a/test/runtime/samples/dev-warning-each-block-no-sets-maps/_config.js b/test/runtime/samples/dev-warning-each-block-no-sets-maps/_config.js
new file mode 100644
index 0000000000..83481d9ebe
--- /dev/null
+++ b/test/runtime/samples/dev-warning-each-block-no-sets-maps/_config.js
@@ -0,0 +1,6 @@
+export default {
+	compileOptions: {
+		dev: true
+	},
+	error: `{#each} only iterates over array-like objects. You can use a spread to convert this iterable into an array.`
+};
diff --git a/test/runtime/samples/dev-warning-each-block-no-sets-maps/main.svelte b/test/runtime/samples/dev-warning-each-block-no-sets-maps/main.svelte
new file mode 100644
index 0000000000..e1aae26d12
--- /dev/null
+++ b/test/runtime/samples/dev-warning-each-block-no-sets-maps/main.svelte
@@ -0,0 +1,7 @@
+<script>
+	const foo = new Set([1, 2, 3]);
+</script>
+
+{#each foo as item}
+	<div>{item}</div>
+{/each}
\ No newline at end of file
diff --git a/test/runtime/samples/dev-warning-each-block-require-arraylike/_config.js b/test/runtime/samples/dev-warning-each-block-require-arraylike/_config.js
new file mode 100644
index 0000000000..62e5fc209b
--- /dev/null
+++ b/test/runtime/samples/dev-warning-each-block-require-arraylike/_config.js
@@ -0,0 +1,6 @@
+export default {
+	compileOptions: {
+		dev: true
+	},
+	error: `{#each} only iterates over array-like objects.`
+};
diff --git a/test/runtime/samples/dev-warning-each-block-require-arraylike/main.svelte b/test/runtime/samples/dev-warning-each-block-require-arraylike/main.svelte
new file mode 100644
index 0000000000..f85df8d84b
--- /dev/null
+++ b/test/runtime/samples/dev-warning-each-block-require-arraylike/main.svelte
@@ -0,0 +1,3 @@
+{#each {} as item}
+	<div>{item}</div>
+{/each}
\ No newline at end of file

From 423d1fe14ece0defb2f68fd3709a77991890aa28 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Tue, 18 Feb 2020 04:52:37 -0500
Subject: [PATCH 68/82] update changelog

---
 CHANGELOG.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index fb8cada5e5..922bc08c92 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,7 @@
 * Warn when using `<Foo/>` and `Foo` is dynamic ([#4331](https://github.com/sveltejs/svelte/issues/4331))
 * Display compilation warnings in `svelte/register` in dev mode ([#4364](https://github.com/sveltejs/svelte/issues/4364))
 * Fix unneeded updating of keyed each blocks ([#4373](https://github.com/sveltejs/svelte/issues/4373))
+* Throw runtime error in dev mode for non-array-like values in `{#each}` blocks ([#4408](https://github.com/sveltejs/svelte/issues/4408))
 
 ## 3.18.2
 

From c992f7a2d2351dcd754d03c66e0b191e96c60511 Mon Sep 17 00:00:00 2001
From: Jesse Skinner <jesse@thefutureoftheweb.com>
Date: Thu, 20 Feb 2020 08:49:34 -0500
Subject: [PATCH 69/82] docs: reword to avoid "outroing" (#4434)

---
 site/content/docs/02-template-syntax.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/site/content/docs/02-template-syntax.md b/site/content/docs/02-template-syntax.md
index 0a4ca2ee1a..1d71dfe9a2 100644
--- a/site/content/docs/02-template-syntax.md
+++ b/site/content/docs/02-template-syntax.md
@@ -795,7 +795,7 @@ transition = (node: HTMLElement, params: any) => {
 
 A transition is triggered by an element entering or leaving the DOM as a result of a state change.
 
-Elements inside an *outroing* block are kept in the DOM until all current transitions have completed.
+When a block is transitioning out, elements inside the block are kept in the DOM until all current transitions have completed.
 
 The `transition:` directive indicates a *bidirectional* transition, which means it can be smoothly reversed while the transition is in progress.
 

From 1772c3f7f14fbca8d75f8c76bdeeb440fb85ac54 Mon Sep 17 00:00:00 2001
From: Rich Harris <richard.a.harris@gmail.com>
Date: Fri, 21 Feb 2020 08:55:38 -0500
Subject: [PATCH 70/82] Remove CI badge (#4438)

---
 README.md | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/README.md b/README.md
index e05154bd7c..3a43725637 100644
--- a/README.md
+++ b/README.md
@@ -7,11 +7,6 @@
     <img src="https://img.shields.io/npm/v/svelte.svg" alt="npm version">
   </a>
 
-  <a href="https://github.com/sveltejs/svelte/actions">
-    <img src="https://github.com/sveltejs/svelte/workflows/CI/badge.svg?branch=master"
-         alt="build status">
-  </a>
-
   <a href="https://github.com/sveltejs/svelte/blob/master/LICENSE">
     <img src="https://img.shields.io/npm/l/svelte.svg" alt="license">
   </a>

From 9a747e3b5abcc1c8ec357634e52cdb1dd9f9314d Mon Sep 17 00:00:00 2001
From: Alexandre CANTIN <cantin.alexandre@gmail.com>
Date: Sun, 23 Feb 2020 05:37:21 +0100
Subject: [PATCH 71/82] site: fix loading REPL with filename containing
 multiple '.'s (#4441)

---
 site/src/routes/repl/[id]/index.svelte | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/site/src/routes/repl/[id]/index.svelte b/site/src/routes/repl/[id]/index.svelte
index 4d05ac28ea..b237e19967 100644
--- a/site/src/routes/repl/[id]/index.svelte
+++ b/site/src/routes/repl/[id]/index.svelte
@@ -57,7 +57,10 @@
 					is_relaxed_gist = data.relaxed;
 
 					const components = data.files.map(file => {
-						let [name, type] = file.name.split('.');
+						const dot = file.name.lastIndexOf(".");
+						let name = file.name.slice(0, dot);
+						let type = file.name.slice(dot + 1);
+
 						if (type === 'html') type = 'svelte'; // TODO do this on the server
 						return { name, type, source: file.source };
 					});

From a53da7e4b062a12f7cf6003416bdf383e087eb36 Mon Sep 17 00:00:00 2001
From: Matthew Dempsky <matthew@dempsky.org>
Date: Sat, 22 Feb 2020 20:40:07 -0800
Subject: [PATCH 72/82] site: clearer examples for <slot let:name> (#4125)

---
 site/content/docs/02-template-syntax.md | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/site/content/docs/02-template-syntax.md b/site/content/docs/02-template-syntax.md
index 1d71dfe9a2..55b913ca94 100644
--- a/site/content/docs/02-template-syntax.md
+++ b/site/content/docs/02-template-syntax.md
@@ -1249,15 +1249,15 @@ The usual shorthand rules apply — `let:item` is equivalent to `let:item={item}
 
 ```html
 <!-- App.svelte -->
-<FancyList {items} let:item={item}>
-	<div>{item.text}</div>
+<FancyList {items} let:prop={thing}>
+	<div>{thing.text}</div>
 </FancyList>
 
 <!-- FancyList.svelte -->
 <ul>
 	{#each items as item}
 		<li class="fancy">
-			<slot item={item}></slot>
+			<slot prop={item}></slot>
 		</li>
 	{/each}
 </ul>
@@ -1270,7 +1270,7 @@ Named slots can also expose values. The `let:` directive goes on the element wit
 ```html
 <!-- App.svelte -->
 <FancyList {items}>
-	<div slot="item" let:item={item}>{item.text}</div>
+	<div slot="item" let:item>{item.text}</div>
 	<p slot="footer">Copyright (c) 2019 Svelte Industries</p>
 </FancyList>
 
@@ -1278,7 +1278,7 @@ Named slots can also expose values. The `let:` directive goes on the element wit
 <ul>
 	{#each items as item}
 		<li class="fancy">
-			<slot name="item" item={item}></slot>
+			<slot name="item" {item}></slot>
 		</li>
 	{/each}
 </ul>

From cb64fb2ac94b3f0a579f75abbbbbe4f4d4a6eef3 Mon Sep 17 00:00:00 2001
From: rixo <eric@rixo.fr>
Date: Sun, 23 Feb 2020 05:13:59 -0800
Subject: [PATCH 73/82] make $capture_state/$inject_state act on entire state
 (#3822)

Previously, these methods only applied to exported props.

Also, add $$inject option to constructor, which injects state before
running the update loop.
---
 src/compiler/compile/render_dom/index.ts      |  61 ++++--
 src/runtime/internal/dev.ts                   |   4 +
 .../samples/capture-inject-state/_config.js   |   5 +
 .../samples/capture-inject-state/expected.js  | 197 ++++++++++++++++++
 .../samples/capture-inject-state/input.svelte |  23 ++
 test/js/samples/debug-empty/expected.js       |   8 +-
 .../debug-foo-bar-baz-things/expected.js      |   8 +-
 test/js/samples/debug-foo/expected.js         |   8 +-
 test/js/samples/debug-hoisted/expected.js     |  11 +-
 .../expected.js                               |   8 +-
 test/js/samples/loop-protect/expected.js      |   8 +-
 11 files changed, 298 insertions(+), 43 deletions(-)
 create mode 100644 test/js/samples/capture-inject-state/_config.js
 create mode 100644 test/js/samples/capture-inject-state/expected.js
 create mode 100644 test/js/samples/capture-inject-state/input.svelte

diff --git a/src/compiler/compile/render_dom/index.ts b/src/compiler/compile/render_dom/index.ts
index a7a55b8843..17e5eaf750 100644
--- a/src/compiler/compile/render_dom/index.ts
+++ b/src/compiler/compile/render_dom/index.ts
@@ -91,7 +91,10 @@ export default function dom(
 	const accessors = [];
 
 	const not_equal = component.component_options.immutable ? x`@not_equal` : x`@safe_not_equal`;
-	let dev_props_check; let inject_state; let capture_state;
+	let dev_props_check: Node[] | Node;
+	let inject_state: Expression;
+	let capture_state: Expression;
+	let props_inject: Node[] | Node;
 
 	props.forEach(prop => {
 		const variable = component.var_lookup.get(prop.name);
@@ -164,27 +167,30 @@ export default function dom(
 			`;
 		}
 
-		capture_state = (uses_props || writable_props.length > 0) ? x`
-			() => {
-				return { ${component.vars.filter(prop => prop.writable).map(prop => p`${prop.name}`)} };
-			}
-		` : x`
-			() => {
-				return {};
-			}
-		`;
+		const capturable_vars = component.vars.filter(v => !v.internal && !v.name.startsWith('$$'));
 
-		const writable_vars = component.vars.filter(variable => !variable.module && variable.writable);
-		inject_state = (uses_props || writable_vars.length > 0) ? x`
-			${$$props} => {
-				${uses_props && renderer.invalidate('$$props', x`$$props = @assign(@assign({}, $$props), $$new_props)`)}
-				${writable_vars.map(prop => b`
-					if ('${prop.name}' in $$props) ${renderer.invalidate(prop.name, x`${prop.name} = ${$$props}.${prop.name}`)};
-				`)}
-			}
-		` : x`
-			${$$props} => {}
-		`;
+		if (capturable_vars.length > 0) {
+			capture_state = x`() => ({ ${capturable_vars.map(prop => p`${prop.name}`)} })`;
+		}
+
+		const injectable_vars = capturable_vars.filter(v => !v.module && v.writable && v.name[0] !== '$');
+
+		if (uses_props || injectable_vars.length > 0) {
+			inject_state = x`
+				${$$props} => {
+					${uses_props && renderer.invalidate('$$props', x`$$props = @assign(@assign({}, $$props), $$new_props)`)}
+					${injectable_vars.map(
+						v => b`if ('${v.name}' in $$props) ${renderer.invalidate(v.name, x`${v.name} = ${$$props}.${v.name}`)};`
+					)}
+				}
+			`;
+
+			props_inject = b`
+				if ($$props && "$$inject" in $$props) {
+					$$self.$inject_state($$props.$$inject);
+				}
+			`;
+		}
 	}
 
 	// instrument assignments
@@ -246,7 +252,12 @@ export default function dom(
 	}
 
 	const args = [x`$$self`];
-	if (props.length > 0 || component.has_reactive_assignments || component.slots.size > 0) {
+	const has_invalidate = props.length > 0 ||
+		component.has_reactive_assignments ||
+		component.slots.size > 0 ||
+		capture_state ||
+		inject_state;
+	if (has_invalidate) {
 		args.push(x`$$props`, x`$$invalidate`);
 	}
 
@@ -294,7 +305,9 @@ export default function dom(
 		uses_props ||
 		component.partly_hoisted.length > 0 ||
 		initial_context.length > 0 ||
-		component.reactive_declarations.length > 0
+		component.reactive_declarations.length > 0 ||
+		capture_state ||
+		inject_state
 	);
 
 	const definition = has_definition
@@ -409,6 +422,8 @@ export default function dom(
 
 				${injected.map(name => b`let ${name};`)}
 
+				${/* before reactive declarations */ props_inject}
+
 				${reactive_declarations.length > 0 && b`
 				$$self.$$.update = () => {
 					${reactive_declarations}
diff --git a/src/runtime/internal/dev.ts b/src/runtime/internal/dev.ts
index 7f4b52eb3b..2d60ffb985 100644
--- a/src/runtime/internal/dev.ts
+++ b/src/runtime/internal/dev.ts
@@ -120,6 +120,10 @@ export class SvelteComponentDev extends SvelteComponent {
 			console.warn(`Component was already destroyed`); // eslint-disable-line no-console
 		};
 	}
+
+	$capture_state() {}
+
+	$inject_state() {}
 }
 
 export function loop_guard(timeout) {
diff --git a/test/js/samples/capture-inject-state/_config.js b/test/js/samples/capture-inject-state/_config.js
new file mode 100644
index 0000000000..414b026a97
--- /dev/null
+++ b/test/js/samples/capture-inject-state/_config.js
@@ -0,0 +1,5 @@
+export default {
+	options: {
+		dev: true
+	}
+};
diff --git a/test/js/samples/capture-inject-state/expected.js b/test/js/samples/capture-inject-state/expected.js
new file mode 100644
index 0000000000..8593145565
--- /dev/null
+++ b/test/js/samples/capture-inject-state/expected.js
@@ -0,0 +1,197 @@
+/* generated by Svelte vX.Y.Z */
+import {
+	SvelteComponentDev,
+	add_location,
+	append_dev,
+	detach_dev,
+	dispatch_dev,
+	element,
+	init,
+	insert_dev,
+	noop,
+	safe_not_equal,
+	set_data_dev,
+	space,
+	subscribe,
+	text,
+	validate_store
+} from "svelte/internal";
+
+const file = undefined;
+
+function create_fragment(ctx) {
+	let p;
+	let t0;
+	let t1;
+	let t2;
+	let t3;
+	let t4;
+	let t5;
+	let t6;
+	let t7;
+	let t8;
+	let t9;
+	let t10;
+
+	const block = {
+		c: function create() {
+			p = element("p");
+			t0 = text(/*prop*/ ctx[0]);
+			t1 = space();
+			t2 = text(/*realName*/ ctx[1]);
+			t3 = space();
+			t4 = text(/*local*/ ctx[3]);
+			t5 = space();
+			t6 = text(priv);
+			t7 = space();
+			t8 = text(/*$prop*/ ctx[2]);
+			t9 = space();
+			t10 = text(/*shadowedByModule*/ ctx[4]);
+			add_location(p, file, 22, 0, 430);
+		},
+		l: function claim(nodes) {
+			throw new Error("options.hydrate only works if the component was compiled with the `hydratable: true` option");
+		},
+		m: function mount(target, anchor) {
+			insert_dev(target, p, anchor);
+			append_dev(p, t0);
+			append_dev(p, t1);
+			append_dev(p, t2);
+			append_dev(p, t3);
+			append_dev(p, t4);
+			append_dev(p, t5);
+			append_dev(p, t6);
+			append_dev(p, t7);
+			append_dev(p, t8);
+			append_dev(p, t9);
+			append_dev(p, t10);
+		},
+		p: function update(ctx, [dirty]) {
+			if (dirty & /*prop*/ 1) set_data_dev(t0, /*prop*/ ctx[0]);
+			if (dirty & /*realName*/ 2) set_data_dev(t2, /*realName*/ ctx[1]);
+			if (dirty & /*$prop*/ 4) set_data_dev(t8, /*$prop*/ ctx[2]);
+		},
+		i: noop,
+		o: noop,
+		d: function destroy(detaching) {
+			if (detaching) detach_dev(p);
+		}
+	};
+
+	dispatch_dev("SvelteRegisterBlock", {
+		block,
+		id: create_fragment.name,
+		type: "component",
+		source: "",
+		ctx
+	});
+
+	return block;
+}
+
+let moduleLiveBinding;
+const moduleContantProps = 4;
+let moduleLet;
+const moduleConst = 2;
+let shadowedByModule;
+const priv = "priv";
+
+function instance($$self, $$props, $$invalidate) {
+	let $prop,
+		$$unsubscribe_prop = noop,
+		$$subscribe_prop = () => ($$unsubscribe_prop(), $$unsubscribe_prop = subscribe(prop, $$value => $$invalidate(2, $prop = $$value)), prop);
+
+	$$self.$$.on_destroy.push(() => $$unsubscribe_prop());
+	let { prop } = $$props;
+	validate_store(prop, "prop");
+	$$subscribe_prop();
+	let { alias: realName } = $$props;
+	let local;
+	let shadowedByModule;
+	const writable_props = ["prop", "alias"];
+
+	Object.keys($$props).forEach(key => {
+		if (!~writable_props.indexOf(key) && key.slice(0, 2) !== "$$") console.warn(`<Component> was created with unknown prop '${key}'`);
+	});
+
+	$$self.$set = $$props => {
+		if ("prop" in $$props) $$subscribe_prop($$invalidate(0, prop = $$props.prop));
+		if ("alias" in $$props) $$invalidate(1, realName = $$props.alias);
+	};
+
+	$$self.$capture_state = () => ({
+		moduleLiveBinding,
+		moduleContantProps,
+		moduleLet,
+		moduleConst,
+		shadowedByModule,
+		prop,
+		realName,
+		local,
+		priv,
+		shadowedByModule,
+		computed,
+		$prop
+	});
+
+	$$self.$inject_state = $$props => {
+		if ("prop" in $$props) $$subscribe_prop($$invalidate(0, prop = $$props.prop));
+		if ("realName" in $$props) $$invalidate(1, realName = $$props.realName);
+		if ("local" in $$props) $$invalidate(3, local = $$props.local);
+		if ("shadowedByModule" in $$props) $$invalidate(4, shadowedByModule = $$props.shadowedByModule);
+		if ("computed" in $$props) computed = $$props.computed;
+	};
+
+	let computed;
+
+	if ($$props && "$$inject" in $$props) {
+		$$self.$inject_state($$props.$$inject);
+	}
+
+	$: computed = local * 2;
+	return [prop, realName, $prop, local, shadowedByModule];
+}
+
+class Component extends SvelteComponentDev {
+	constructor(options) {
+		super(options);
+		init(this, options, instance, create_fragment, safe_not_equal, { prop: 0, alias: 1 });
+
+		dispatch_dev("SvelteRegisterComponent", {
+			component: this,
+			tagName: "Component",
+			options,
+			id: create_fragment.name
+		});
+
+		const { ctx } = this.$$;
+		const props = options.props || {};
+
+		if (/*prop*/ ctx[0] === undefined && !("prop" in props)) {
+			console.warn("<Component> was created without expected prop 'prop'");
+		}
+
+		if (/*realName*/ ctx[1] === undefined && !("alias" in props)) {
+			console.warn("<Component> was created without expected prop 'alias'");
+		}
+	}
+
+	get prop() {
+		throw new Error("<Component>: Props cannot be read directly from the component instance unless compiling with 'accessors: true' or '<svelte:options accessors/>'");
+	}
+
+	set prop(value) {
+		throw new Error("<Component>: Props cannot be set directly on the component instance unless compiling with 'accessors: true' or '<svelte:options accessors/>'");
+	}
+
+	get alias() {
+		throw new Error("<Component>: Props cannot be read directly from the component instance unless compiling with 'accessors: true' or '<svelte:options accessors/>'");
+	}
+
+	set alias(value) {
+		throw new Error("<Component>: Props cannot be set directly on the component instance unless compiling with 'accessors: true' or '<svelte:options accessors/>'");
+	}
+}
+
+export default Component;
+export { moduleLiveBinding, moduleContantProps };
\ No newline at end of file
diff --git a/test/js/samples/capture-inject-state/input.svelte b/test/js/samples/capture-inject-state/input.svelte
new file mode 100644
index 0000000000..a1051bc147
--- /dev/null
+++ b/test/js/samples/capture-inject-state/input.svelte
@@ -0,0 +1,23 @@
+<script context="module">
+  export let moduleLiveBinding;
+  export const moduleContantProps = 4;
+  let moduleLet;
+  const moduleConst = 2;
+  let shadowedByModule;
+</script>
+<script>
+  export let prop;
+
+  let realName;
+  export { realName as alias };
+
+  let local;
+
+  const priv = 'priv';
+
+  $: computed = local * 2;
+
+  let shadowedByModule;
+</script>
+<!-- NOTE $prop ensures store subscriptions are not part of captured state -->
+<p>{prop} {realName} {local} {priv} {$prop} {shadowedByModule}</p>
diff --git a/test/js/samples/debug-empty/expected.js b/test/js/samples/debug-empty/expected.js
index 358363c661..87d78bd698 100644
--- a/test/js/samples/debug-empty/expected.js
+++ b/test/js/samples/debug-empty/expected.js
@@ -79,14 +79,16 @@ function instance($$self, $$props, $$invalidate) {
 		if ("name" in $$props) $$invalidate(0, name = $$props.name);
 	};
 
-	$$self.$capture_state = () => {
-		return { name };
-	};
+	$$self.$capture_state = () => ({ name });
 
 	$$self.$inject_state = $$props => {
 		if ("name" in $$props) $$invalidate(0, name = $$props.name);
 	};
 
+	if ($$props && "$$inject" in $$props) {
+		$$self.$inject_state($$props.$$inject);
+	}
+
 	return [name];
 }
 
diff --git a/test/js/samples/debug-foo-bar-baz-things/expected.js b/test/js/samples/debug-foo-bar-baz-things/expected.js
index 3209afe8a2..589c4a7832 100644
--- a/test/js/samples/debug-foo-bar-baz-things/expected.js
+++ b/test/js/samples/debug-foo-bar-baz-things/expected.js
@@ -186,9 +186,7 @@ function instance($$self, $$props, $$invalidate) {
 		if ("baz" in $$props) $$invalidate(3, baz = $$props.baz);
 	};
 
-	$$self.$capture_state = () => {
-		return { things, foo, bar, baz };
-	};
+	$$self.$capture_state = () => ({ things, foo, bar, baz });
 
 	$$self.$inject_state = $$props => {
 		if ("things" in $$props) $$invalidate(0, things = $$props.things);
@@ -197,6 +195,10 @@ function instance($$self, $$props, $$invalidate) {
 		if ("baz" in $$props) $$invalidate(3, baz = $$props.baz);
 	};
 
+	if ($$props && "$$inject" in $$props) {
+		$$self.$inject_state($$props.$$inject);
+	}
+
 	return [things, foo, bar, baz];
 }
 
diff --git a/test/js/samples/debug-foo/expected.js b/test/js/samples/debug-foo/expected.js
index 4b08be44d9..10129e1b28 100644
--- a/test/js/samples/debug-foo/expected.js
+++ b/test/js/samples/debug-foo/expected.js
@@ -176,15 +176,17 @@ function instance($$self, $$props, $$invalidate) {
 		if ("foo" in $$props) $$invalidate(1, foo = $$props.foo);
 	};
 
-	$$self.$capture_state = () => {
-		return { things, foo };
-	};
+	$$self.$capture_state = () => ({ things, foo });
 
 	$$self.$inject_state = $$props => {
 		if ("things" in $$props) $$invalidate(0, things = $$props.things);
 		if ("foo" in $$props) $$invalidate(1, foo = $$props.foo);
 	};
 
+	if ($$props && "$$inject" in $$props) {
+		$$self.$inject_state($$props.$$inject);
+	}
+
 	return [things, foo];
 }
 
diff --git a/test/js/samples/debug-hoisted/expected.js b/test/js/samples/debug-hoisted/expected.js
index eeb9465499..c77168ef4f 100644
--- a/test/js/samples/debug-hoisted/expected.js
+++ b/test/js/samples/debug-hoisted/expected.js
@@ -47,19 +47,20 @@ function create_fragment(ctx) {
 	return block;
 }
 
-function instance($$self) {
+function instance($$self, $$props, $$invalidate) {
 	let obj = { x: 5 };
 	let kobzol = 5;
-
-	$$self.$capture_state = () => {
-		return {};
-	};
+	$$self.$capture_state = () => ({ obj, kobzol });
 
 	$$self.$inject_state = $$props => {
 		if ("obj" in $$props) $$invalidate(0, obj = $$props.obj);
 		if ("kobzol" in $$props) $$invalidate(1, kobzol = $$props.kobzol);
 	};
 
+	if ($$props && "$$inject" in $$props) {
+		$$self.$inject_state($$props.$$inject);
+	}
+
 	return [obj, kobzol];
 }
 
diff --git a/test/js/samples/dev-warning-missing-data-computed/expected.js b/test/js/samples/dev-warning-missing-data-computed/expected.js
index cc16de67e6..9c28e04064 100644
--- a/test/js/samples/dev-warning-missing-data-computed/expected.js
+++ b/test/js/samples/dev-warning-missing-data-computed/expected.js
@@ -76,15 +76,17 @@ function instance($$self, $$props, $$invalidate) {
 		if ("foo" in $$props) $$invalidate(0, foo = $$props.foo);
 	};
 
-	$$self.$capture_state = () => {
-		return { foo, bar };
-	};
+	$$self.$capture_state = () => ({ foo, bar });
 
 	$$self.$inject_state = $$props => {
 		if ("foo" in $$props) $$invalidate(0, foo = $$props.foo);
 		if ("bar" in $$props) $$invalidate(1, bar = $$props.bar);
 	};
 
+	if ($$props && "$$inject" in $$props) {
+		$$self.$inject_state($$props.$$inject);
+	}
+
 	$$self.$$.update = () => {
 		if ($$self.$$.dirty & /*foo*/ 1) {
 			$: $$invalidate(1, bar = foo * 2);
diff --git a/test/js/samples/loop-protect/expected.js b/test/js/samples/loop-protect/expected.js
index 554ccf23b1..127addf1d1 100644
--- a/test/js/samples/loop-protect/expected.js
+++ b/test/js/samples/loop-protect/expected.js
@@ -108,14 +108,16 @@ function instance($$self, $$props, $$invalidate) {
 		});
 	}
 
-	$$self.$capture_state = () => {
-		return {};
-	};
+	$$self.$capture_state = () => ({ node, foo, console });
 
 	$$self.$inject_state = $$props => {
 		if ("node" in $$props) $$invalidate(0, node = $$props.node);
 	};
 
+	if ($$props && "$$inject" in $$props) {
+		$$self.$inject_state($$props.$$inject);
+	}
+
 	$: {
 		const guard_4 = loop_guard(100);
 

From a7ffceefdd007a933eedd93dae53aed55b6290b9 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Sun, 23 Feb 2020 08:16:27 -0500
Subject: [PATCH 74/82] update changelog

---
 CHANGELOG.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 922bc08c92..05468d7368 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@
 ## Unreleased
 
 * Fix indirect bindings involving elements with spreads ([#3680](https://github.com/sveltejs/svelte/issues/3680))
+* `$capture_state`/`$inject_state` now act on the component's entire state, rather than its props ([#3822](https://github.com/sveltejs/svelte/pull/3822))
 * Warn when using `<Foo/>` and `Foo` is dynamic ([#4331](https://github.com/sveltejs/svelte/issues/4331))
 * Display compilation warnings in `svelte/register` in dev mode ([#4364](https://github.com/sveltejs/svelte/issues/4364))
 * Fix unneeded updating of keyed each blocks ([#4373](https://github.com/sveltejs/svelte/issues/4373))

From a972a47e14b110c50ca31993fae28e8ddf677a4b Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Sun, 23 Feb 2020 08:41:22 -0500
Subject: [PATCH 75/82] -> v3.19.0

---
 CHANGELOG.md      | 2 +-
 package-lock.json | 2 +-
 package.json      | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 05468d7368..f81b198154 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,6 @@
 # Svelte changelog
 
-## Unreleased
+## 3.19.0
 
 * Fix indirect bindings involving elements with spreads ([#3680](https://github.com/sveltejs/svelte/issues/3680))
 * `$capture_state`/`$inject_state` now act on the component's entire state, rather than its props ([#3822](https://github.com/sveltejs/svelte/pull/3822))
diff --git a/package-lock.json b/package-lock.json
index 8f0b7469f8..2454010c0d 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "svelte",
-  "version": "3.18.2",
+  "version": "3.19.0",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
diff --git a/package.json b/package.json
index 6000e9d1c4..1cb0d10eeb 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "svelte",
-  "version": "3.18.2",
+  "version": "3.19.0",
   "description": "Cybernetically enhanced web apps",
   "module": "index.mjs",
   "main": "index",

From 138213ca3c1ca91998461e961933d630aeb45b15 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Sun, 23 Feb 2020 16:35:25 -0500
Subject: [PATCH 76/82] fix dev mode each block validation when using strings
 (#4451)

---
 CHANGELOG.md                                       |  4 ++++
 src/runtime/internal/dev.ts                        |  2 +-
 test/runtime/samples/each-block-string/_config.js  | 10 ++++++++++
 test/runtime/samples/each-block-string/main.svelte |  3 +++
 4 files changed, 18 insertions(+), 1 deletion(-)
 create mode 100644 test/runtime/samples/each-block-string/_config.js
 create mode 100644 test/runtime/samples/each-block-string/main.svelte

diff --git a/CHANGELOG.md b/CHANGELOG.md
index f81b198154..3f4460cde4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Svelte changelog
 
+## Unreleased
+
+* Fix dev mode validation of `{#each}` blocks using strings ([#4450](https://github.com/sveltejs/svelte/issues/4450))
+
 ## 3.19.0
 
 * Fix indirect bindings involving elements with spreads ([#3680](https://github.com/sveltejs/svelte/issues/3680))
diff --git a/src/runtime/internal/dev.ts b/src/runtime/internal/dev.ts
index 2d60ffb985..8aefc88ba7 100644
--- a/src/runtime/internal/dev.ts
+++ b/src/runtime/internal/dev.ts
@@ -80,7 +80,7 @@ export function set_data_dev(text, data) {
 }
 
 export function validate_each_argument(arg) {
-	if (!arg || !('length' in arg)) {
+	if (typeof arg !== 'string' && !(arg && typeof arg === 'object' && 'length' in arg)) {
 		let msg = '{#each} only iterates over array-like objects.';
 		if (typeof Symbol === 'function' && arg && Symbol.iterator in arg) {
 			msg += ' You can use a spread to convert this iterable into an array.';
diff --git a/test/runtime/samples/each-block-string/_config.js b/test/runtime/samples/each-block-string/_config.js
new file mode 100644
index 0000000000..7366c964eb
--- /dev/null
+++ b/test/runtime/samples/each-block-string/_config.js
@@ -0,0 +1,10 @@
+export default {
+	compileOptions: {
+		dev: true
+	},
+	html: `
+		<div>f</div>
+		<div>o</div>
+		<div>o</div>
+	`
+};
diff --git a/test/runtime/samples/each-block-string/main.svelte b/test/runtime/samples/each-block-string/main.svelte
new file mode 100644
index 0000000000..ae60f0f6b3
--- /dev/null
+++ b/test/runtime/samples/each-block-string/main.svelte
@@ -0,0 +1,3 @@
+{#each 'foo' as c}
+	<div>{c}</div>
+{/each}

From 3bfa0e5cd6219ce6408a7bfa6689b3afa1945388 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Sun, 23 Feb 2020 17:50:57 -0500
Subject: [PATCH 77/82] deconflict `value` parameter in contextual bindings
 (#4452)

---
 CHANGELOG.md                                        |  1 +
 .../render_dom/wrappers/InlineComponent/index.ts    | 13 ++++++-------
 .../deconflict-contextual-bind/Widget.svelte        |  3 +++
 .../samples/deconflict-contextual-bind/_config.js   |  3 +++
 .../samples/deconflict-contextual-bind/main.svelte  |  8 ++++++++
 5 files changed, 21 insertions(+), 7 deletions(-)
 create mode 100644 test/runtime/samples/deconflict-contextual-bind/Widget.svelte
 create mode 100644 test/runtime/samples/deconflict-contextual-bind/_config.js
 create mode 100644 test/runtime/samples/deconflict-contextual-bind/main.svelte

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3f4460cde4..2166ca4c9c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+* Deconflict `value` parameter name used in contextual bindings ([#4445](https://github.com/sveltejs/svelte/issues/4445))
 * Fix dev mode validation of `{#each}` blocks using strings ([#4450](https://github.com/sveltejs/svelte/issues/4450))
 
 ## 3.19.0
diff --git a/src/compiler/compile/render_dom/wrappers/InlineComponent/index.ts b/src/compiler/compile/render_dom/wrappers/InlineComponent/index.ts
index f1c57ed094..28b3c938f9 100644
--- a/src/compiler/compile/render_dom/wrappers/InlineComponent/index.ts
+++ b/src/compiler/compile/render_dom/wrappers/InlineComponent/index.ts
@@ -332,8 +332,7 @@ export default class InlineComponentWrapper extends Wrapper {
 				contextual_dependencies.push(object.name, property.name);
 			}
 
-			const value = block.get_unique_name('value');
-			const params: any[] = [value];
+			const params = [x`#value`];
 			if (contextual_dependencies.length > 0) {
 				const args = [];
 
@@ -349,23 +348,23 @@ export default class InlineComponentWrapper extends Wrapper {
 
 
 				block.chunks.init.push(b`
-					function ${id}(${value}) {
-						${callee}.call(null, ${value}, ${args});
+					function ${id}(#value) {
+						${callee}.call(null, #value, ${args});
 					}
 				`);
 
 				block.maintain_context = true; // TODO put this somewhere more logical
 			} else {
 				block.chunks.init.push(b`
-					function ${id}(${value}) {
-						${callee}.call(null, ${value});
+					function ${id}(#value) {
+						${callee}.call(null, #value);
 					}
 				`);
 			}
 
 			const body = b`
 				function ${id}(${params}) {
-					${lhs} = ${value};
+					${lhs} = #value;
 					${renderer.invalidate(dependencies[0])};
 				}
 			`;
diff --git a/test/runtime/samples/deconflict-contextual-bind/Widget.svelte b/test/runtime/samples/deconflict-contextual-bind/Widget.svelte
new file mode 100644
index 0000000000..3aaa59b747
--- /dev/null
+++ b/test/runtime/samples/deconflict-contextual-bind/Widget.svelte
@@ -0,0 +1,3 @@
+<script>
+	export let prop;
+</script>
diff --git a/test/runtime/samples/deconflict-contextual-bind/_config.js b/test/runtime/samples/deconflict-contextual-bind/_config.js
new file mode 100644
index 0000000000..7602cde023
--- /dev/null
+++ b/test/runtime/samples/deconflict-contextual-bind/_config.js
@@ -0,0 +1,3 @@
+export default {
+	preserveIdentifiers: true
+};
diff --git a/test/runtime/samples/deconflict-contextual-bind/main.svelte b/test/runtime/samples/deconflict-contextual-bind/main.svelte
new file mode 100644
index 0000000000..fe91deca17
--- /dev/null
+++ b/test/runtime/samples/deconflict-contextual-bind/main.svelte
@@ -0,0 +1,8 @@
+<script>
+	import Widget from './Widget.svelte';
+	const values = ['foo', 'bar'];
+</script>
+
+{#each values as value}
+	<Widget bind:value/>
+{/each}

From 19f1c9cb7c4818fdb10e56b650465e1b2f40c6bc Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Sun, 23 Feb 2020 18:19:06 -0500
Subject: [PATCH 78/82] don't treat $$-names as stores during invalidation
 (#4453)

---
 CHANGELOG.md                                  | 1 +
 src/compiler/compile/render_dom/invalidate.ts | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2166ca4c9c..d3687b3d2a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+* Do not treat modifications to `$$props` as updates to a store called `$props` ([#4368](https://github.com/sveltejs/svelte/issues/4368))
 * Deconflict `value` parameter name used in contextual bindings ([#4445](https://github.com/sveltejs/svelte/issues/4445))
 * Fix dev mode validation of `{#each}` blocks using strings ([#4450](https://github.com/sveltejs/svelte/issues/4450))
 
diff --git a/src/compiler/compile/render_dom/invalidate.ts b/src/compiler/compile/render_dom/invalidate.ts
index 20aff05d1e..28e4f37e3f 100644
--- a/src/compiler/compile/render_dom/invalidate.ts
+++ b/src/compiler/compile/render_dom/invalidate.ts
@@ -43,7 +43,7 @@ export function invalidate(renderer: Renderer, scope: Scope, node: Node, names:
 		if (node.type === 'AssignmentExpression' && node.operator === '=' && nodes_match(node.left, node.right) && tail.length === 0) {
 			return get_invalidated(head, node);
 		} else {
-			const is_store_value = head.name[0] === '$';
+			const is_store_value = head.name[0] === '$' && head.name[1] !== '$';
 			const extra_args = tail.map(variable => get_invalidated(variable));
 
 			const pass_value = (

From b8bf3643d4590fee3afe5aae733e2ccc4547c110 Mon Sep 17 00:00:00 2001
From: Conduitry <git@chor.date>
Date: Sun, 23 Feb 2020 18:28:30 -0500
Subject: [PATCH 79/82] -> v3.19.1

---
 CHANGELOG.md      | 2 +-
 package-lock.json | 2 +-
 package.json      | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index d3687b3d2a..28c24fa066 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,6 @@
 # Svelte changelog
 
-## Unreleased
+## 3.19.1
 
 * Do not treat modifications to `$$props` as updates to a store called `$props` ([#4368](https://github.com/sveltejs/svelte/issues/4368))
 * Deconflict `value` parameter name used in contextual bindings ([#4445](https://github.com/sveltejs/svelte/issues/4445))
diff --git a/package-lock.json b/package-lock.json
index 2454010c0d..3b275078ec 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "svelte",
-  "version": "3.19.0",
+  "version": "3.19.1",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
diff --git a/package.json b/package.json
index 1cb0d10eeb..7a02f1da10 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "svelte",
-  "version": "3.19.0",
+  "version": "3.19.1",
   "description": "Cybernetically enhanced web apps",
   "module": "index.mjs",
   "main": "index",

From e1d2cfb74873f3dc5f1234fb31fef3be5415fb24 Mon Sep 17 00:00:00 2001
From: Jesse Skinner <jesse@thefutureoftheweb.com>
Date: Mon, 24 Feb 2020 20:39:42 -0500
Subject: [PATCH 80/82] Update wording to include prop behaviour

In regards to #4442, this adds wording to explain that props are set to undefined when they are removed by the consumer.
---
 site/content/docs/01-component-format.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/site/content/docs/01-component-format.md b/site/content/docs/01-component-format.md
index 026a2da5b3..2101a0c7de 100644
--- a/site/content/docs/01-component-format.md
+++ b/site/content/docs/01-component-format.md
@@ -42,7 +42,7 @@ Svelte uses the `export` keyword to mark a variable declaration as a *property*
 
 ---
 
-You can specify a default value, which will be used if the component's consumer doesn't specify a prop.
+You can specify a default value for a prop. It will be used if the component's consumer doesn't specify the prop on the component. Note that whenever a specified prop is removed by the consumer, the value is set to `undefined` rather than the default value.
 
 In development mode (see the [compiler options](docs#svelte_compile)), a warning will be printed if no default is provided and the consumer does not specify a value. To squelch this warning, ensure that a default is specified, even if it is `undefined`.
 

From e496e81d6fce78f3799acc7938776ab272accef3 Mon Sep 17 00:00:00 2001
From: Jesse Skinner <jesse@thefutureoftheweb.com>
Date: Thu, 27 Feb 2020 08:42:20 -0500
Subject: [PATCH 81/82] Change 'default value' to 'initial value' to set
 expectations about behaviour, for issue #4442

---
 site/content/docs/01-component-format.md | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/site/content/docs/01-component-format.md b/site/content/docs/01-component-format.md
index 2101a0c7de..f202dd355c 100644
--- a/site/content/docs/01-component-format.md
+++ b/site/content/docs/01-component-format.md
@@ -42,13 +42,13 @@ Svelte uses the `export` keyword to mark a variable declaration as a *property*
 
 ---
 
-You can specify a default value for a prop. It will be used if the component's consumer doesn't specify the prop on the component. Note that whenever a specified prop is removed by the consumer, the value is set to `undefined` rather than the default value.
+You can specify an initial value for a prop. It will be used if the component's consumer doesn't specify the prop on the component. Note that whenever a specified prop is removed by the consumer, the value is set to `undefined` rather than the initial value.
 
-In development mode (see the [compiler options](docs#svelte_compile)), a warning will be printed if no default is provided and the consumer does not specify a value. To squelch this warning, ensure that a default is specified, even if it is `undefined`.
+In development mode (see the [compiler options](docs#svelte_compile)), a warning will be printed if no initial value is provided and the consumer does not specify a value. To squelch this warning, ensure that an initial value is specified, even if it is `undefined`.
 
 ```html
 <script>
-	export let bar = 'optional default value';
+	export let bar = 'optional initial value';
 	export let baz = undefined;
 </script>
 ```

From bfe1b2c5306053999d006d7f7bc1af5af607e9b4 Mon Sep 17 00:00:00 2001
From: Jesse Skinner <jesse@thefutureoftheweb.com>
Date: Thu, 27 Feb 2020 12:11:16 -0500
Subject: [PATCH 82/82] Update site/content/docs/01-component-format.md

Co-Authored-By: Luca Bonavita <mindrones@users.noreply.github.com>
---
 site/content/docs/01-component-format.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/site/content/docs/01-component-format.md b/site/content/docs/01-component-format.md
index f202dd355c..95689c1a59 100644
--- a/site/content/docs/01-component-format.md
+++ b/site/content/docs/01-component-format.md
@@ -42,7 +42,7 @@ Svelte uses the `export` keyword to mark a variable declaration as a *property*
 
 ---
 
-You can specify an initial value for a prop. It will be used if the component's consumer doesn't specify the prop on the component. Note that whenever a specified prop is removed by the consumer, the value is set to `undefined` rather than the initial value.
+You can specify a default initial value for a prop. It will be used if the component's consumer doesn't specify the prop on the component (or if its initial value is `undefined`). Note that whenever a prop is removed by the consumer, its value is set to `undefined` rather than the initial value.
 
 In development mode (see the [compiler options](docs#svelte_compile)), a warning will be printed if no initial value is provided and the consumer does not specify a value. To squelch this warning, ensure that an initial value is specified, even if it is `undefined`.