diff --git a/package-lock.json b/package-lock.json
index 059554afd8..12fb4d00bd 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "svelte",
-  "version": "3.0.0-beta.20",
+  "version": "3.0.0-beta.21",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
diff --git a/package.json b/package.json
index 72e3785315..f9aa16656d 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "svelte",
-  "version": "3.0.0-beta.20",
+  "version": "3.0.0-beta.21",
   "description": "The magical disappearing UI framework",
   "module": "index.mjs",
   "main": "index",
diff --git a/site/content/blog/2018-12-27-virtual-dom-is-pure-overhead.md b/site/content/blog/2018-12-27-virtual-dom-is-pure-overhead.md
index 062745b192..f70bda43d5 100644
--- a/site/content/blog/2018-12-27-virtual-dom-is-pure-overhead.md
+++ b/site/content/blog/2018-12-27-virtual-dom-is-pure-overhead.md
@@ -121,7 +121,7 @@ function MoreRealisticComponent(props) {
 			<p>Selected {selected ? selected.name : 'nothing'}</p>
 
 			<ul>
-				${props.items.map(item =>
+				{props.items.map(item =>
 					<li>
 						<button onClick={() => setSelected(item)}>
 							{item.name}
@@ -147,4 +147,4 @@ Svelte is explicitly designed to prevent you from ending up in that situation.
 
 It's important to understand that virtual DOM *isn't a feature*. It's a means to an end, the end being declarative, state-driven UI development. Virtual DOM is valuable because it allows you to build apps without thinking about state transitions, with performance that is *generally good enough*. That means less buggy code, and more time spent on creative tasks instead of tedious ones.
 
-But it turns out that we can achieve a similar programming model without using virtual DOM — and that's where Svelte comes in.
\ No newline at end of file
+But it turns out that we can achieve a similar programming model without using virtual DOM — and that's where Svelte comes in.
diff --git a/site/content/tutorial/06-bindings/09-media-elements/app-a/App.svelte b/site/content/tutorial/06-bindings/09-media-elements/app-a/App.svelte
index a80588d398..ec01cd5476 100644
--- a/site/content/tutorial/06-bindings/09-media-elements/app-a/App.svelte
+++ b/site/content/tutorial/06-bindings/09-media-elements/app-a/App.svelte
@@ -109,8 +109,8 @@
 
 <div>
 	<video
-		poster="http://svelte-assets.surge.sh/caminandes-llamigos.jpg"
-		src="http://svelte-assets.surge.sh/caminandes-llamigos.mp4"
+		poster="https://svelte-assets.surge.sh/caminandes-llamigos.jpg"
+		src="https://svelte-assets.surge.sh/caminandes-llamigos.mp4"
 		on:mousemove={handleMousemove}
 		on:mousedown={handleMousedown}
 	></video>
diff --git a/site/content/tutorial/06-bindings/09-media-elements/app-b/App.svelte b/site/content/tutorial/06-bindings/09-media-elements/app-b/App.svelte
index 2cf819fca0..c304581a77 100644
--- a/site/content/tutorial/06-bindings/09-media-elements/app-b/App.svelte
+++ b/site/content/tutorial/06-bindings/09-media-elements/app-b/App.svelte
@@ -109,8 +109,8 @@
 
 <div>
 	<video
-		poster="http://svelte-assets.surge.sh/caminandes-llamigos.jpg"
-		src="http://svelte-assets.surge.sh/caminandes-llamigos.mp4"
+		poster="https://svelte-assets.surge.sh/caminandes-llamigos.jpg"
+		src="https://svelte-assets.surge.sh/caminandes-llamigos.mp4"
 		on:mousemove={handleMousemove}
 		on:mousedown={handleMousedown}
 		bind:currentTime={time}
diff --git a/site/src/routes/repl/index.svelte b/site/src/routes/repl/index.svelte
index 655b8144a8..2cd99db38e 100644
--- a/site/src/routes/repl/index.svelte
+++ b/site/src/routes/repl/index.svelte
@@ -10,14 +10,13 @@
 
 <script>
 	import { onMount } from 'svelte';
-	import { locate } from 'locate-character';
 	import { process_example } from '../../components/Repl/process_example.js';
 	import AppControls from './_components/AppControls/index.svelte';
 	import Repl from '../../components/Repl/index.svelte';
 
-	export let version, example, gist_id;
-
-	console.log({ example });
+	export let version;
+	export let example;
+	export let gist_id;
 
 	let repl;
 	let gist;
@@ -52,7 +51,7 @@
 			relaxed = false;
 			fetch(`gist/${gist_id}`).then(r => r.json()).then(data => {
 				gist = data;
-				const { id, description, files } = data;
+				const { description, files } = data;
 
 				name = description;
 
@@ -84,36 +83,28 @@
 
 				repl.set({ components });
 			});
-		}
-	});
+		} else {
+			relaxed = true;
+			fetch(`examples/${example}.json`).then(async response => {
+				if (response.ok) {
+					const data = await response.json();
 
-	function load_example(slug) {
-		console.log(`loading ${slug}`);
+					name = data.title;
 
-		relaxed = true;
-		fetch(`examples/${slug}.json`).then(async response => {
-			if (response.ok) {
-				const data = await response.json();
-
-				name = data.title;
-
-				const components = process_example(data.files);
-				repl.set({ components });
+					const components = process_example(data.files);
+					repl.set({ components });
 
-				gist = null;
-			}
-		});
-	}
+					gist = null;
+				}
+			});
+		}
+	});
 
 	function handle_fork(event) {
 		example = null;
 		gist = event.detail.gist;
 		gist_id = gist.id;
 	}
-
-	$: if (process.browser && example) {
-		load_example(example);
-	}
 </script>
 
 <style>
@@ -134,7 +125,7 @@
 		width: 100%;
 		height: 100%;
 		top: 0;
-		z-index: 11;
+		z-index: 111;
 	}
 
 	.pane { width: 100%; height: 100% }
diff --git a/src/compile/Component.ts b/src/compile/Component.ts
index 30a06ca50b..f8ee5a0b78 100644
--- a/src/compile/Component.ts
+++ b/src/compile/Component.ts
@@ -648,7 +648,7 @@ export default class Component {
 				this.add_reference(name.slice(1));
 
 				const variable = this.var_lookup.get(name.slice(1));
-				variable.subscribable = true;
+				if (variable) variable.subscribable = true;
 			} else {
 				this.add_var({
 					name,
@@ -1164,9 +1164,11 @@ export default class Component {
 		const variable = this.var_lookup.get(name);
 
 		if (!variable) return name;
-		if (variable && variable.hoistable) return name;
 
 		this.add_reference(name); // TODO we can probably remove most other occurrences of this
+
+		if (variable.hoistable) return name;
+
 		return `ctx.${name}`;
 	}
 
diff --git a/src/compile/nodes/Element.ts b/src/compile/nodes/Element.ts
index 536e1e729a..6d9c8059f5 100644
--- a/src/compile/nodes/Element.ts
+++ b/src/compile/nodes/Element.ts
@@ -493,11 +493,12 @@ export default class Element extends Node {
 					});
 				}
 
-				if (check_type_attribute() !== 'checkbox') {
-					component.error(binding, {
-						code: `invalid-binding`,
-						message: `'${name}' binding can only be used with <input type="checkbox">`
-					});
+				const type = check_type_attribute();
+
+				if (type !== 'checkbox') {
+					let message = `'${name}' binding can only be used with <input type="checkbox">`;
+					if (type === 'radio') message += ` — for <input type="radio">, use 'group' binding`;
+					component.error(binding, { code: `invalid-binding`, message });
 				}
 			} else if (name === 'group') {
 				if (this.name !== 'input') {
@@ -512,14 +513,14 @@ export default class Element extends Node {
 				if (type !== 'checkbox' && type !== 'radio') {
 					component.error(binding, {
 						code: `invalid-binding`,
-						message: `'checked' binding can only be used with <input type="checkbox"> or <input type="radio">`
+						message: `'group' binding can only be used with <input type="checkbox"> or <input type="radio">`
 					});
 				}
 			} else if (name == 'files') {
 				if (this.name !== 'input') {
 					component.error(binding, {
 						code: `invalid-binding`,
-						message: `'files' binding acn only be used with <input type="file">`
+						message: `'files' is not a valid binding on <${this.name}> elements`
 					});
 				}
 
@@ -635,23 +636,6 @@ export default class Element extends Node {
 		});
 	}
 
-	get_static_attribute_value(name: string) {
-		const attribute = this.attributes.find(
-			(attr: Attribute) => attr.type === 'Attribute' && attr.name.toLowerCase() === name
-		);
-
-		if (!attribute) return null;
-
-		if (attribute.is_true) return true;
-		if (attribute.chunks.length === 0) return '';
-
-		if (attribute.chunks.length === 1 && attribute.chunks[0].type === 'Text') {
-			return attribute.chunks[0].data;
-		}
-
-		return null;
-	}
-
 	is_media_node() {
 		return this.name === 'audio' || this.name === 'video';
 	}
diff --git a/src/compile/nodes/Slot.ts b/src/compile/nodes/Slot.ts
index 0a4f4af848..1540fa6271 100644
--- a/src/compile/nodes/Slot.ts
+++ b/src/compile/nodes/Slot.ts
@@ -5,6 +5,7 @@ import Attribute from './Attribute';
 export default class Slot extends Element {
 	type: 'Element';
 	name: string;
+	slot_name: string;
 	attributes: Attribute[];
 	children: Node[];
 
@@ -27,8 +28,8 @@ export default class Slot extends Element {
 					});
 				}
 
-				const slot_name = attr.value[0].data;
-				if (slot_name === 'default') {
+				this.slot_name = attr.value[0].data;
+				if (this.slot_name === 'default') {
 					component.error(attr, {
 						code: `invalid-slot-name`,
 						message: `default is a reserved word — it cannot be used as a slot name`
@@ -46,6 +47,8 @@ export default class Slot extends Element {
 			// validator.slots.add(slot_name);
 		});
 
+		if (!this.slot_name) this.slot_name = 'default';
+
 		// if (node.attributes.length === 0) && validator.slots.has('default')) {
 		// 	validator.error(node, {
 		// 		code: `duplicate-slot`,
@@ -53,21 +56,4 @@ export default class Slot extends Element {
 		// 	});
 		// }
 	}
-
-	get_static_attribute_value(name: string) {
-		const attribute = this.attributes.find(
-			attr => attr.name.toLowerCase() === name
-		);
-
-		if (!attribute) return null;
-
-		if (attribute.is_true) return true;
-		if (attribute.chunks.length === 0) return '';
-
-		if (attribute.chunks.length === 1 && attribute.chunks[0].type === 'Text') {
-			return attribute.chunks[0].data;
-		}
-
-		return null;
-	}
 }
\ No newline at end of file
diff --git a/src/compile/nodes/shared/Expression.ts b/src/compile/nodes/shared/Expression.ts
index 4d8e831078..22cb403f75 100644
--- a/src/compile/nodes/shared/Expression.ts
+++ b/src/compile/nodes/shared/Expression.ts
@@ -364,7 +364,18 @@ export default class Expression {
 					let body = code.slice(node.body.start, node.body.end).trim();
 					if (node.body.type !== 'BlockStatement') {
 						if (pending_assignments.size > 0) {
-							const insert = Array.from(pending_assignments).map(name => component.invalidate(name)).join('; ');
+							const dependencies = new Set();
+							pending_assignments.forEach(name => {
+								if (template_scope.names.has(name)) {
+									template_scope.dependencies_for_name.get(name).forEach(dependency => {
+										dependencies.add(dependency);
+									});
+								} else {
+									dependencies.add(name);
+								}
+							});
+
+							const insert = Array.from(dependencies).map(name => component.invalidate(name)).join('; ');
 							pending_assignments = new Set();
 
 							component.has_reactive_assignments = true;
diff --git a/src/compile/nodes/shared/Node.ts b/src/compile/nodes/shared/Node.ts
index 4317e23e4f..92c1cc40d7 100644
--- a/src/compile/nodes/shared/Node.ts
+++ b/src/compile/nodes/shared/Node.ts
@@ -37,17 +37,34 @@ export default class Node {
 		}
 	}
 
+	find_nearest(selector: RegExp) {
+		if (selector.test(this.type)) return this;
+		if (this.parent) return this.parent.find_nearest(selector);
+	}
+
+	get_static_attribute_value(name: string) {
+		const attribute = this.attributes.find(
+			(attr: Attribute) => attr.type === 'Attribute' && attr.name.toLowerCase() === name
+		);
+
+		if (!attribute) return null;
+
+		if (attribute.is_true) return true;
+		if (attribute.chunks.length === 0) return '';
+
+		if (attribute.chunks.length === 1 && attribute.chunks[0].type === 'Text') {
+			return attribute.chunks[0].data;
+		}
+
+		return null;
+	}
+
 	has_ancestor(type: string) {
 		return this.parent ?
 			this.parent.type === type || this.parent.has_ancestor(type) :
 			false;
 	}
 
-	find_nearest(selector: RegExp) {
-		if (selector.test(this.type)) return this;
-		if (this.parent) return this.parent.find_nearest(selector);
-	}
-
 	warn_if_empty_block() {
 		if (!/Block$/.test(this.type) || !this.children) return;
 		if (this.children.length > 1) return;
diff --git a/src/compile/render-dom/index.ts b/src/compile/render-dom/index.ts
index aef29a194b..363d807916 100644
--- a/src/compile/render-dom/index.ts
+++ b/src/compile/render-dom/index.ts
@@ -10,7 +10,6 @@ import add_to_set from '../utils/add_to_set';
 import get_object from '../utils/get_object';
 import { extract_names } from '../utils/scope';
 import { nodes_match } from '../../utils/nodes_match';
-import { sanitize } from '../../utils/names';
 
 export default function dom(
 	component: Component,
@@ -305,8 +304,7 @@ export default function dom(
 	const reactive_stores = component.vars.filter(variable => variable.name[0] === '$' && variable.name[1] !== '$');
 
 	if (renderer.slots.size > 0) {
-		const arr = Array.from(renderer.slots);
-		filtered_declarations.push(...arr.map(name => `$$slot_${sanitize(name)}`), '$$scope');
+		filtered_declarations.push('$$slots', '$$scope');
 	}
 
 	if (renderer.binding_groups.length > 0) {
@@ -399,7 +397,7 @@ export default function dom(
 
 				${component.javascript}
 
-				${renderer.slots.size && `let { ${[...renderer.slots].map(name => `$$slot_${sanitize(name)}`).join(', ')}, $$scope } = $$props;`}
+				${renderer.slots.size && `let { $$slots = {}, $$scope } = $$props;`}
 
 				${renderer.binding_groups.length > 0 && `const $$binding_groups = [${renderer.binding_groups.map(_ => `[]`).join(', ')}];`}
 
diff --git a/src/compile/render-dom/wrappers/EachBlock.ts b/src/compile/render-dom/wrappers/EachBlock.ts
index 4c2504e8c3..cc9ebed833 100644
--- a/src/compile/render-dom/wrappers/EachBlock.ts
+++ b/src/compile/render-dom/wrappers/EachBlock.ts
@@ -207,8 +207,8 @@ export default class EachBlockWrapper extends Wrapper {
 		if (needs_anchor) {
 			block.add_element(
 				this.vars.anchor,
-				`@comment()`,
-				parent_nodes && `@comment()`,
+				`@empty()`,
+				parent_nodes && `@empty()`,
 				parent_node
 			);
 		}
@@ -300,8 +300,8 @@ export default class EachBlockWrapper extends Wrapper {
 			this.block.first = this.block.get_unique_name('first');
 			this.block.add_element(
 				this.block.first,
-				`@comment()`,
-				parent_nodes && `@comment()`,
+				`@empty()`,
+				parent_nodes && `@empty()`,
 				null
 			);
 		}
diff --git a/src/compile/render-dom/wrappers/Element/Attribute.ts b/src/compile/render-dom/wrappers/Element/Attribute.ts
index 5b581677d8..c0c8327bb0 100644
--- a/src/compile/render-dom/wrappers/Element/Attribute.ts
+++ b/src/compile/render-dom/wrappers/Element/Attribute.ts
@@ -117,7 +117,7 @@ export default class AttributeWrapper {
 				updater = `@set_input_type(${element.var}, ${should_cache ? last : value});`;
 			} else if (is_select_value_attribute) {
 				// annoying special case
-				const is_multiple_select = element.get_static_attribute_value('multiple');
+				const is_multiple_select = element.node.get_static_attribute_value('multiple');
 				const i = block.get_unique_name('i');
 				const option = block.get_unique_name('option');
 
diff --git a/src/compile/render-dom/wrappers/Element/Binding.ts b/src/compile/render-dom/wrappers/Element/Binding.ts
index 8657a1b054..f2bf82a826 100644
--- a/src/compile/render-dom/wrappers/Element/Binding.ts
+++ b/src/compile/render-dom/wrappers/Element/Binding.ts
@@ -153,7 +153,7 @@ export default class BindingWrapper {
 				break;
 
 			case 'value':
-				if (parent.get_static_attribute_value('type') === 'file') {
+				if (parent.node.get_static_attribute_value('type') === 'file') {
 					update_dom = null;
 				}
 		}
diff --git a/src/compile/render-dom/wrappers/Element/index.ts b/src/compile/render-dom/wrappers/Element/index.ts
index d54a66dffa..fa025bacbe 100644
--- a/src/compile/render-dom/wrappers/Element/index.ts
+++ b/src/compile/render-dom/wrappers/Element/index.ts
@@ -20,6 +20,7 @@ import add_event_handlers from '../shared/add_event_handlers';
 import add_actions from '../shared/add_actions';
 import create_debugging_comment from '../shared/create_debugging_comment';
 import { get_context_merger } from '../shared/get_context_merger';
+import Slot from '../../../nodes/Slot';
 
 const events = [
 	{
@@ -213,8 +214,7 @@ export default class ElementWrapper extends Wrapper {
 		const { renderer } = this;
 
 		if (this.node.name === 'slot') {
-			const slotName = this.get_static_attribute_value('name') || 'default';
-			renderer.slots.add(slotName);
+			renderer.slots.add((this.node as Slot).slot_name);
 		}
 
 		if (this.node.name === 'noscript') return;
@@ -804,23 +804,6 @@ export default class ElementWrapper extends Wrapper {
 		});
 	}
 
-	get_static_attribute_value(name: string) {
-		const attribute = this.node.attributes.find(
-			(attr: Attribute) => attr.type === 'Attribute' && attr.name.toLowerCase() === name
-		);
-
-		if (!attribute) return null;
-
-		if (attribute.is_true) return true;
-		if (attribute.chunks.length === 0) return '';
-
-		if (attribute.chunks.length === 1 && attribute.chunks[0].type === 'Text') {
-			return attribute.chunks[0].data;
-		}
-
-		return null;
-	}
-
 	add_css_class(class_name = this.component.stylesheet.id) {
 		const class_attribute = this.attributes.find(a => a.name === 'class');
 		if (class_attribute && !class_attribute.is_true) {
diff --git a/src/compile/render-dom/wrappers/IfBlock.ts b/src/compile/render-dom/wrappers/IfBlock.ts
index 2051429fda..f3b5c7f2b2 100644
--- a/src/compile/render-dom/wrappers/IfBlock.ts
+++ b/src/compile/render-dom/wrappers/IfBlock.ts
@@ -185,8 +185,8 @@ export default class IfBlockWrapper extends Wrapper {
 		if (needs_anchor) {
 			block.add_element(
 				anchor,
-				`@comment()`,
-				parent_nodes && `@comment()`,
+				`@empty()`,
+				parent_nodes && `@empty()`,
 				parent_node
 			);
 		}
diff --git a/src/compile/render-dom/wrappers/InlineComponent/index.ts b/src/compile/render-dom/wrappers/InlineComponent/index.ts
index 958a98bcb5..bc13014a29 100644
--- a/src/compile/render-dom/wrappers/InlineComponent/index.ts
+++ b/src/compile/render-dom/wrappers/InlineComponent/index.ts
@@ -119,16 +119,19 @@ export default class InlineComponentWrapper extends Wrapper {
 
 		const uses_spread = !!this.node.attributes.find(a => a.is_spread);
 
-		const slot_props = Array.from(this.slots).map(([name, slot]) => `$$slot_${sanitize(name)}: [${slot.block.name}${slot.fn ? `, ${slot.fn}` : ''}]`);
-		if (slot_props.length > 0) slot_props.push(`$$scope: { ctx }`);
+		const slot_props = Array.from(this.slots).map(([name, slot]) => `${quote_name_if_necessary(name)}: [${slot.block.name}${slot.fn ? `, ${slot.fn}` : ''}]`);
+
+		const initial_props = slot_props.length > 0
+			? [`$$slots: ${stringify_props(slot_props)}`, `$$scope: { ctx }`]
+			: [];
 
 		const attribute_object = uses_spread
-			? stringify_props(slot_props)
+			? stringify_props(initial_props)
 			: stringify_props(
-				this.node.attributes.map(attr => `${quote_name_if_necessary(attr.name)}: ${attr.get_value(block)}`).concat(slot_props)
+				this.node.attributes.map(attr => `${quote_name_if_necessary(attr.name)}: ${attr.get_value(block)}`).concat(initial_props)
 			);
 
-		if (this.node.attributes.length || this.node.bindings.length || slot_props.length) {
+		if (this.node.attributes.length || this.node.bindings.length || initial_props.length) {
 			if (!uses_spread && this.node.bindings.length === 0) {
 				component_opts.push(`props: ${attribute_object}`);
 			} else {
diff --git a/src/compile/render-dom/wrappers/Slot.ts b/src/compile/render-dom/wrappers/Slot.ts
index e21baaa717..38896b4546 100644
--- a/src/compile/render-dom/wrappers/Slot.ts
+++ b/src/compile/render-dom/wrappers/Slot.ts
@@ -4,7 +4,7 @@ import Block from '../Block';
 import Slot from '../../nodes/Slot';
 import FragmentWrapper from './Fragment';
 import deindent from '../../utils/deindent';
-import { sanitize } from '../../../utils/names';
+import { sanitize, quote_prop_if_necessary } from '../../../utils/names';
 import add_to_set from '../../utils/add_to_set';
 import get_slot_data from '../../utils/get_slot_data';
 import { stringify_props } from '../../utils/stringify_props';
@@ -42,6 +42,10 @@ export default class SlotWrapper extends Wrapper {
 		});
 
 		block.add_dependencies(this.dependencies);
+
+		// we have to do this, just in case
+		block.add_intro();
+		block.add_outro();
 	}
 
 	render(
@@ -51,7 +55,7 @@ export default class SlotWrapper extends Wrapper {
 	) {
 		const { renderer } = this;
 
-		const slot_name = this.node.get_static_attribute_value('name') || 'default';
+		const { slot_name } = this.node;
 		renderer.slots.add(slot_name);
 
 		let get_slot_changes;
@@ -95,7 +99,7 @@ export default class SlotWrapper extends Wrapper {
 		const slot_definition = block.get_unique_name(`${sanitize(slot_name)}_slot`);
 
 		block.builders.init.add_block(deindent`
-			const ${slot_definition} = ctx.$$slot_${sanitize(slot_name)};
+			const ${slot_definition} = ctx.$$slots${quote_prop_if_necessary(slot_name)};
 			const ${slot} = @create_slot(${slot_definition}, ctx, ${get_slot_context});
 		`);
 
@@ -137,6 +141,14 @@ export default class SlotWrapper extends Wrapper {
 			}
 		`);
 
+		block.builders.intro.add_line(
+			`if (${slot} && ${slot}.i) ${slot}.i(#local);`
+		);
+
+		block.builders.outro.add_line(
+			`if (${slot} && ${slot}.o) ${slot}.o(#local);`
+		);
+
 		let update_conditions = [...this.dependencies].map(name => `changed.${name}`).join(' || ');
 		if (this.dependencies.size > 1) update_conditions = `(${update_conditions})`;
 
diff --git a/src/compile/render-dom/wrappers/shared/Wrapper.ts b/src/compile/render-dom/wrappers/shared/Wrapper.ts
index 7ec5868b20..2a9394415f 100644
--- a/src/compile/render-dom/wrappers/shared/Wrapper.ts
+++ b/src/compile/render-dom/wrappers/shared/Wrapper.ts
@@ -53,8 +53,8 @@ export default class Wrapper {
 		if (needs_anchor) {
 			block.add_element(
 				anchor,
-				`@comment()`,
-				parent_nodes && `@comment()`,
+				`@empty()`,
+				parent_nodes && `@empty()`,
 				parent_node
 			);
 		}
diff --git a/src/compile/render-ssr/handlers/Slot.ts b/src/compile/render-ssr/handlers/Slot.ts
index 51e37ab9cf..77273e8009 100644
--- a/src/compile/render-ssr/handlers/Slot.ts
+++ b/src/compile/render-ssr/handlers/Slot.ts
@@ -2,10 +2,7 @@ import { quote_prop_if_necessary } from '../../../utils/names';
 import get_slot_data from '../../utils/get_slot_data';
 
 export default function(node, renderer, options) {
-	const name = node.attributes.find(attribute => attribute.name === 'name');
-
-	const slot_name = name && name.chunks[0].data || 'default';
-	const prop = quote_prop_if_necessary(slot_name);
+	const prop = quote_prop_if_necessary(node.slot_name);
 
 	const slot_data = get_slot_data(node.attributes, true);
 
diff --git a/src/internal/dom.js b/src/internal/dom.js
index 1c22bf4c70..2d661b5958 100644
--- a/src/internal/dom.js
+++ b/src/internal/dom.js
@@ -50,8 +50,8 @@ export function space() {
 	return text(' ');
 }
 
-export function comment() {
-	return document.createComment('');
+export function empty() {
+	return text('');
 }
 
 export function listen(node, event, handler, options) {
diff --git a/src/parse/state/tag.ts b/src/parse/state/tag.ts
index dc7c0c3d5a..3747d2d482 100644
--- a/src/parse/state/tag.ts
+++ b/src/parse/state/tag.ts
@@ -191,8 +191,7 @@ export default function tag(parser: Parser) {
 	}
 
 	if (name === 'svelte:component') {
-		// TODO post v2, treat this just as any other attribute
-		const index = element.attributes.findIndex(attr => attr.name === 'this');
+		const index = element.attributes.findIndex(attr => attr.type === 'Attribute' && attr.name === 'this');
 		if (!~index) {
 			parser.error({
 				code: `missing-component-definition`,
diff --git a/src/utils/names.ts b/src/utils/names.ts
index 5047fe850c..1f0a9cc29e 100644
--- a/src/utils/names.ts
+++ b/src/utils/names.ts
@@ -111,5 +111,9 @@ export function quote_prop_if_necessary(name: string) {
 }
 
 export function sanitize(name: string) {
-	return name.replace(/[^a-zA-Z]+/g, '_').replace(/^_/, '').replace(/_$/, '');
-}
\ No newline at end of file
+	return name
+		.replace(/[^a-zA-Z0-9_]+/g, '_')
+		.replace(/^_/, '')
+		.replace(/_$/, '')
+		.replace(/^[0-9]/, '_$&');
+}
diff --git a/store.mjs b/store.mjs
index faafe31575..c4b98e9072 100644
--- a/store.mjs
+++ b/store.mjs
@@ -1,8 +1,9 @@
 import { run_all, noop, get_store_value, safe_not_equal } from './internal';
 
-export function readable(start, value) {
-	const { set, subscribe } = writable(value, () => start(set));
-	return { subscribe };
+export function readable(value, start) {
+	return {
+		subscribe: writable(value, start).subscribe
+	};
 }
 
 export function writable(value, start = noop) {
@@ -25,7 +26,7 @@ export function writable(value, start = noop) {
 	function subscribe(run, invalidate = noop) {
 		const subscriber = [run, invalidate];
 		subscribers.push(subscriber);
-		if (subscribers.length === 1) stop = start() || noop;
+		if (subscribers.length === 1) stop = start(set) || noop;
 		run(value);
 
 		return () => {
@@ -45,7 +46,7 @@ export function derive(stores, fn) {
 	const auto = fn.length < 2;
 	let value = {};
 
-	return readable(set => {
+	return readable(undefined, set => {
 		let inited = false;
 		const values = [];
 
diff --git a/test/js/samples/deconflict-builtins/expected.js b/test/js/samples/deconflict-builtins/expected.js
index 32bbdb4394..3985faa362 100644
--- a/test/js/samples/deconflict-builtins/expected.js
+++ b/test/js/samples/deconflict-builtins/expected.js
@@ -2,10 +2,10 @@
 import {
 	SvelteComponent as SvelteComponent_1,
 	append,
-	comment,
 	destroy_each,
 	detach,
 	element,
+	empty,
 	init,
 	insert,
 	noop,
@@ -66,7 +66,7 @@ function create_fragment(ctx) {
 				each_blocks[i].c();
 			}
 
-			each_1_anchor = comment();
+			each_1_anchor = empty();
 		},
 
 		m(target, anchor) {
diff --git a/test/js/samples/each-block-array-literal/expected.js b/test/js/samples/each-block-array-literal/expected.js
index be3b4a3b45..766cfceb71 100644
--- a/test/js/samples/each-block-array-literal/expected.js
+++ b/test/js/samples/each-block-array-literal/expected.js
@@ -2,10 +2,10 @@
 import {
 	SvelteComponent as SvelteComponent_1,
 	append,
-	comment,
 	destroy_each,
 	detach,
 	element,
+	empty,
 	init,
 	insert,
 	noop,
@@ -66,7 +66,7 @@ function create_fragment(ctx) {
 				each_blocks[i].c();
 			}
 
-			each_1_anchor = comment();
+			each_1_anchor = empty();
 		},
 
 		m(target, anchor) {
diff --git a/test/js/samples/each-block-keyed-animated/expected.js b/test/js/samples/each-block-keyed-animated/expected.js
index fd879530ea..aa9215b56d 100644
--- a/test/js/samples/each-block-keyed-animated/expected.js
+++ b/test/js/samples/each-block-keyed-animated/expected.js
@@ -3,10 +3,10 @@ import {
 	SvelteComponent as SvelteComponent_1,
 	append,
 	blank_object,
-	comment,
 	create_animation,
 	detach,
 	element,
+	empty,
 	fix_and_outro_and_destroy_block,
 	fix_position,
 	init,
@@ -89,7 +89,7 @@ function create_fragment(ctx) {
 		c() {
 			for (i = 0; i < each_blocks.length; i += 1) each_blocks[i].c();
 
-			each_1_anchor = comment();
+			each_1_anchor = empty();
 		},
 
 		m(target, anchor) {
diff --git a/test/js/samples/each-block-keyed/expected.js b/test/js/samples/each-block-keyed/expected.js
index c20a43d4d4..8688d3af9a 100644
--- a/test/js/samples/each-block-keyed/expected.js
+++ b/test/js/samples/each-block-keyed/expected.js
@@ -3,10 +3,10 @@ import {
 	SvelteComponent as SvelteComponent_1,
 	append,
 	blank_object,
-	comment,
 	destroy_block,
 	detach,
 	element,
+	empty,
 	init,
 	insert,
 	noop,
@@ -73,7 +73,7 @@ function create_fragment(ctx) {
 		c() {
 			for (i = 0; i < each_blocks.length; i += 1) each_blocks[i].c();
 
-			each_1_anchor = comment();
+			each_1_anchor = empty();
 		},
 
 		m(target, anchor) {
diff --git a/test/js/samples/if-block-no-update/expected.js b/test/js/samples/if-block-no-update/expected.js
index 11fbf604b1..1605696736 100644
--- a/test/js/samples/if-block-no-update/expected.js
+++ b/test/js/samples/if-block-no-update/expected.js
@@ -1,9 +1,9 @@
 /* generated by Svelte vX.Y.Z */
 import {
 	SvelteComponent as SvelteComponent_1,
-	comment,
 	detach,
 	element,
+	empty,
 	init,
 	insert,
 	noop,
@@ -68,7 +68,7 @@ function create_fragment(ctx) {
 	return {
 		c() {
 			if_block.c();
-			if_block_anchor = comment();
+			if_block_anchor = empty();
 		},
 
 		m(target, anchor) {
diff --git a/test/js/samples/if-block-simple/expected.js b/test/js/samples/if-block-simple/expected.js
index af8d45974f..44c8ed31db 100644
--- a/test/js/samples/if-block-simple/expected.js
+++ b/test/js/samples/if-block-simple/expected.js
@@ -1,9 +1,9 @@
 /* generated by Svelte vX.Y.Z */
 import {
 	SvelteComponent as SvelteComponent_1,
-	comment,
 	detach,
 	element,
+	empty,
 	init,
 	insert,
 	noop,
@@ -40,7 +40,7 @@ function create_fragment(ctx) {
 	return {
 		c() {
 			if (if_block) if_block.c();
-			if_block_anchor = comment();
+			if_block_anchor = empty();
 		},
 
 		m(target, anchor) {
diff --git a/test/js/samples/transition-local/expected.js b/test/js/samples/transition-local/expected.js
index b98d2a4520..85979e9959 100644
--- a/test/js/samples/transition-local/expected.js
+++ b/test/js/samples/transition-local/expected.js
@@ -2,10 +2,10 @@
 import {
 	SvelteComponent as SvelteComponent_1,
 	add_render_callback,
-	comment,
 	create_in_transition,
 	detach,
 	element,
+	empty,
 	init,
 	insert,
 	noop,
@@ -21,7 +21,7 @@ function create_if_block(ctx) {
 	return {
 		c() {
 			if (if_block) if_block.c();
-			if_block_anchor = comment();
+			if_block_anchor = empty();
 		},
 
 		m(target, anchor) {
@@ -98,7 +98,7 @@ function create_fragment(ctx) {
 	return {
 		c() {
 			if (if_block) if_block.c();
-			if_block_anchor = comment();
+			if_block_anchor = empty();
 		},
 
 		m(target, anchor) {
diff --git a/test/js/samples/use-elements-as-anchors/expected.js b/test/js/samples/use-elements-as-anchors/expected.js
index 7277dc8b7d..bb708284b4 100644
--- a/test/js/samples/use-elements-as-anchors/expected.js
+++ b/test/js/samples/use-elements-as-anchors/expected.js
@@ -2,9 +2,9 @@
 import {
 	SvelteComponent as SvelteComponent_1,
 	append,
-	comment,
 	detach,
 	element,
+	empty,
 	init,
 	insert,
 	noop,
@@ -153,7 +153,7 @@ function create_fragment(ctx) {
 			if (if_block3) if_block3.c();
 			t7 = space();
 			if (if_block4) if_block4.c();
-			if_block4_anchor = comment();
+			if_block4_anchor = empty();
 		},
 
 		m(target, anchor) {
diff --git a/test/runtime/samples/component-slot-names-sanitized/Nested.svelte b/test/runtime/samples/component-slot-names-sanitized/Nested.svelte
new file mode 100644
index 0000000000..ca8328920d
--- /dev/null
+++ b/test/runtime/samples/component-slot-names-sanitized/Nested.svelte
@@ -0,0 +1,8 @@
+<div>
+	<slot name="header1" />
+	<slot name="-header2_" />
+	<slot name="3header" />
+	<slot name="_header4" />
+	<slot name="header-5" />
+	<slot name="header&5" />
+</div>
diff --git a/test/runtime/samples/component-slot-names-sanitized/_config.js b/test/runtime/samples/component-slot-names-sanitized/_config.js
new file mode 100644
index 0000000000..d75beb1b05
--- /dev/null
+++ b/test/runtime/samples/component-slot-names-sanitized/_config.js
@@ -0,0 +1,12 @@
+export default {
+	html: `
+		<div>
+			<h1 slot="header1">Header 1</h1>
+			<h2 slot="-header2_">Header 2</h2>
+			<h3 slot="3header">Header 3</h3>
+			<h4 slot="_header4">Header 4</h4>
+			<h5 slot="header-5">Header 5</h5>
+			<h5 slot="header&5">Header 5b</h5>
+		</div>
+	`
+};
diff --git a/test/runtime/samples/component-slot-names-sanitized/main.svelte b/test/runtime/samples/component-slot-names-sanitized/main.svelte
new file mode 100644
index 0000000000..3e607de5fa
--- /dev/null
+++ b/test/runtime/samples/component-slot-names-sanitized/main.svelte
@@ -0,0 +1,12 @@
+<script>
+	import Nested from './Nested.svelte';
+</script>
+
+<Nested>
+	<h1 slot="header1">Header 1</h1>
+	<h2 slot="-header2_">Header 2</h2>
+	<h3 slot="3header">Header 3</h3>
+	<h4 slot="_header4">Header 4</h4>
+	<h5 slot="header-5">Header 5</h5>
+	<h5 slot="header&5">Header 5b</h5>
+</Nested>
diff --git a/test/runtime/samples/dynamic-component-ref/main.svelte b/test/runtime/samples/dynamic-component-ref/main.svelte
index 984f34fc7b..a7e8643cc4 100644
--- a/test/runtime/samples/dynamic-component-ref/main.svelte
+++ b/test/runtime/samples/dynamic-component-ref/main.svelte
@@ -4,4 +4,4 @@
 	export let test;
 </script>
 
-<svelte:component this={Foo} bind:this={test}/>
+<svelte:component bind:this={test} this={Foo}/>
diff --git a/test/runtime/samples/event-handler-each-context-invalidation/_config.js b/test/runtime/samples/event-handler-each-context-invalidation/_config.js
new file mode 100644
index 0000000000..07e7170357
--- /dev/null
+++ b/test/runtime/samples/event-handler-each-context-invalidation/_config.js
@@ -0,0 +1,35 @@
+export default {
+	html: `
+		<button>off</button>
+		<button>on</button>
+		<button>off</button>
+		<p>on: 1</p>
+	`,
+
+	async test({ assert, component, target, window }) {
+		const buttons = target.querySelectorAll('button');
+		const event = new window.MouseEvent('click');
+
+		await buttons[0].dispatchEvent(event);
+		assert.htmlEqual(target.innerHTML, `
+			<button>on</button>
+			<button>on</button>
+			<button>off</button>
+			<p>on: 2</p>
+		`);
+
+		await buttons[2].dispatchEvent(event);
+		assert.htmlEqual(target.innerHTML, `
+			<button>on</button>
+			<button>on</button>
+			<button>on</button>
+			<p>on: 3</p>
+		`);
+
+		assert.deepEqual(component.switches, [
+			{ on: true },
+			{ on: true },
+			{ on: true }
+		]);
+	}
+};
diff --git a/test/runtime/samples/event-handler-each-context-invalidation/main.svelte b/test/runtime/samples/event-handler-each-context-invalidation/main.svelte
new file mode 100644
index 0000000000..77c6b7f197
--- /dev/null
+++ b/test/runtime/samples/event-handler-each-context-invalidation/main.svelte
@@ -0,0 +1,15 @@
+<script>
+	export let switches = [
+		{ on: false },
+		{ on: true },
+		{ on: false }
+	];
+</script>
+
+{#each switches as s}
+	<button on:click="{() => s.on = !s.on}">
+		{s.on ? 'on' : 'off'}
+	</button>
+{/each}
+
+<p>on: {switches.filter(s => !!s.on).length}</p>
\ No newline at end of file
diff --git a/test/runtime/samples/store-auto-subscribe-missing-global/_config.js b/test/runtime/samples/store-auto-subscribe-missing-global-script/_config.js
similarity index 100%
rename from test/runtime/samples/store-auto-subscribe-missing-global/_config.js
rename to test/runtime/samples/store-auto-subscribe-missing-global-script/_config.js
diff --git a/test/runtime/samples/store-auto-subscribe-missing-global-script/main.svelte b/test/runtime/samples/store-auto-subscribe-missing-global-script/main.svelte
new file mode 100644
index 0000000000..210734b71d
--- /dev/null
+++ b/test/runtime/samples/store-auto-subscribe-missing-global-script/main.svelte
@@ -0,0 +1,3 @@
+<script>
+	$: $missingGlobal;
+</script>
diff --git a/test/runtime/samples/store-auto-subscribe-missing-global-template/_config.js b/test/runtime/samples/store-auto-subscribe-missing-global-template/_config.js
new file mode 100644
index 0000000000..c4eb72b553
--- /dev/null
+++ b/test/runtime/samples/store-auto-subscribe-missing-global-template/_config.js
@@ -0,0 +1,3 @@
+export default {
+	error: 'missingGlobal is not defined'
+};
\ No newline at end of file
diff --git a/test/runtime/samples/store-auto-subscribe-missing-global/main.svelte b/test/runtime/samples/store-auto-subscribe-missing-global-template/main.svelte
similarity index 100%
rename from test/runtime/samples/store-auto-subscribe-missing-global/main.svelte
rename to test/runtime/samples/store-auto-subscribe-missing-global-template/main.svelte
diff --git a/test/runtime/samples/transition-js-slot/Nested.svelte b/test/runtime/samples/transition-js-slot/Nested.svelte
new file mode 100644
index 0000000000..bc67b3c221
--- /dev/null
+++ b/test/runtime/samples/transition-js-slot/Nested.svelte
@@ -0,0 +1,9 @@
+<script>
+	export let visible;
+</script>
+
+<div>
+	{#if visible}
+		<slot/>
+	{/if}
+</div>
\ No newline at end of file
diff --git a/test/runtime/samples/transition-js-slot/_config.js b/test/runtime/samples/transition-js-slot/_config.js
new file mode 100644
index 0000000000..a32e4bda72
--- /dev/null
+++ b/test/runtime/samples/transition-js-slot/_config.js
@@ -0,0 +1,26 @@
+export default {
+	props: {
+		visible: false
+	},
+
+	html: `
+		<div></div>
+	`,
+
+	test({ assert, component, target, window, raf }) {
+		component.visible = true;
+		const p = target.querySelector('p');
+		assert.equal(p.foo, 0);
+
+		raf.tick(50);
+		assert.equal(p.foo, 0.5);
+
+		component.visible = false;
+
+		raf.tick(75);
+		assert.equal(p.foo, 0.25);
+
+		raf.tick(100);
+		assert.equal(p.foo, 0);
+	}
+};
\ No newline at end of file
diff --git a/test/runtime/samples/transition-js-slot/main.svelte b/test/runtime/samples/transition-js-slot/main.svelte
new file mode 100644
index 0000000000..afbcd68167
--- /dev/null
+++ b/test/runtime/samples/transition-js-slot/main.svelte
@@ -0,0 +1,18 @@
+<script>
+	import Nested from './Nested.svelte';
+
+	export let visible;
+
+	function foo(node, params) {
+		return {
+			duration: 100,
+			tick: t => {
+				node.foo = t;
+			}
+		};
+	}
+</script>
+
+<Nested {visible}>
+	<p transition:foo>slotted</p>
+</Nested>
\ No newline at end of file
diff --git a/test/store/index.js b/test/store/index.js
index f993c3a253..f077b183e1 100644
--- a/test/store/index.js
+++ b/test/store/index.js
@@ -66,7 +66,7 @@ describe('store', () => {
 			let running;
 			let tick;
 
-			const store = readable(set => {
+			const store = readable(undefined, set => {
 				tick = set;
 				running = true;
 
@@ -192,7 +192,7 @@ describe('store', () => {
 
 	describe('get', () => {
 		it('gets the current value of a store', () => {
-			const store = readable(() => {}, 42);
+			const store = readable(42, () => {});
 			assert.equal(get(store), 42);
 		});
 	});
diff --git a/test/vars/samples/actions/_config.js b/test/vars/samples/actions/_config.js
index 2cda8889c9..6b6f8696e7 100644
--- a/test/vars/samples/actions/_config.js
+++ b/test/vars/samples/actions/_config.js
@@ -1,6 +1,16 @@
 export default {
 	test(assert, vars) {
 		assert.deepEqual(vars, [
+			{
+				export_name: null,
+				injected: false,
+				module: false,
+				mutated: false,
+				name: 'hoistable_foo',
+				reassigned: false,
+				referenced: true,
+				writable: false
+			},
 			{
 				export_name: null,
 				injected: false,
diff --git a/test/vars/samples/actions/input.svelte b/test/vars/samples/actions/input.svelte
index fe614c760c..8ba8f0f21f 100644
--- a/test/vars/samples/actions/input.svelte
+++ b/test/vars/samples/actions/input.svelte
@@ -1,5 +1,7 @@
 <script>
+	import hoistable_foo from '';
 	let foo;
 </script>
 
+<div use:hoistable_foo/>
 <div use:foo/>
diff --git a/test/vars/samples/animations/_config.js b/test/vars/samples/animations/_config.js
index 2cda8889c9..6b6f8696e7 100644
--- a/test/vars/samples/animations/_config.js
+++ b/test/vars/samples/animations/_config.js
@@ -1,6 +1,16 @@
 export default {
 	test(assert, vars) {
 		assert.deepEqual(vars, [
+			{
+				export_name: null,
+				injected: false,
+				module: false,
+				mutated: false,
+				name: 'hoistable_foo',
+				reassigned: false,
+				referenced: true,
+				writable: false
+			},
 			{
 				export_name: null,
 				injected: false,
diff --git a/test/vars/samples/animations/input.svelte b/test/vars/samples/animations/input.svelte
index 7843ab928d..02967d0fa8 100644
--- a/test/vars/samples/animations/input.svelte
+++ b/test/vars/samples/animations/input.svelte
@@ -1,7 +1,11 @@
 <script>
+	import hoistable_foo from '';
 	let foo;
 </script>
 
+{#each [] as x (x)}
+	<div animate:hoistable_foo/>
+{/each}
 {#each [] as x (x)}
 	<div animate:foo/>
 {/each}
diff --git a/test/vars/samples/transitions/_config.js b/test/vars/samples/transitions/_config.js
index e42faf7d19..b2522a1b56 100644
--- a/test/vars/samples/transitions/_config.js
+++ b/test/vars/samples/transitions/_config.js
@@ -1,6 +1,36 @@
 export default {
 	test(assert, vars) {
 		assert.deepEqual(vars, [
+			{
+				export_name: null,
+				injected: false,
+				module: false,
+				mutated: false,
+				name: 'hoistable_foo',
+				reassigned: false,
+				referenced: true,
+				writable: false
+			},
+			{
+				export_name: null,
+				injected: false,
+				module: false,
+				mutated: false,
+				name: 'hoistable_bar',
+				reassigned: false,
+				referenced: true,
+				writable: false
+			},
+			{
+				export_name: null,
+				injected: false,
+				module: false,
+				mutated: false,
+				name: 'hoistable_baz',
+				reassigned: false,
+				referenced: true,
+				writable: false
+			},
 			{
 				export_name: null,
 				injected: false,
diff --git a/test/vars/samples/transitions/input.svelte b/test/vars/samples/transitions/input.svelte
index 1dac9bc5ec..0db2b5289e 100644
--- a/test/vars/samples/transitions/input.svelte
+++ b/test/vars/samples/transitions/input.svelte
@@ -1,9 +1,13 @@
 <script>
+	import { hoistable_foo, hoistable_bar, hoistable_baz } from '';
 	let foo;
 	let bar;
 	let baz;
 </script>
 
+<div in:hoistable_foo/>
+<div out:hoistable_bar/>
+<div transition:hoistable_baz/>
 <div in:foo/>
 <div out:bar/>
 <div transition:baz/>