From cb1a76b08c1766b7f68191583352d7a3ef7c5f04 Mon Sep 17 00:00:00 2001
From: Richard Harris <richard.a.harris@gmail.com>
Date: Mon, 27 May 2019 12:09:21 +0200
Subject: [PATCH] dont create unknown prop warnings for $$scope etc, or if
 component has $$props - fixes #2878

---
 src/compile/render-dom/index.ts                            | 4 ++--
 .../dev-warning-unknown-props-with-$$props/Foo.svelte      | 7 +++++++
 .../dev-warning-unknown-props-with-$$props/_config.js      | 7 +++++++
 .../dev-warning-unknown-props-with-$$props/main.svelte     | 5 +++++
 .../dev-warning-unknown-props-with-$$scope/Foo.svelte      | 6 ++++++
 .../dev-warning-unknown-props-with-$$scope/_config.js      | 7 +++++++
 .../dev-warning-unknown-props-with-$$scope/main.svelte     | 7 +++++++
 7 files changed, 41 insertions(+), 2 deletions(-)
 create mode 100644 test/runtime/samples/dev-warning-unknown-props-with-$$props/Foo.svelte
 create mode 100644 test/runtime/samples/dev-warning-unknown-props-with-$$props/_config.js
 create mode 100644 test/runtime/samples/dev-warning-unknown-props-with-$$props/main.svelte
 create mode 100644 test/runtime/samples/dev-warning-unknown-props-with-$$scope/Foo.svelte
 create mode 100644 test/runtime/samples/dev-warning-unknown-props-with-$$scope/_config.js
 create mode 100644 test/runtime/samples/dev-warning-unknown-props-with-$$scope/main.svelte

diff --git a/src/compile/render-dom/index.ts b/src/compile/render-dom/index.ts
index 1432813e9d..2bf8935150 100644
--- a/src/compile/render-dom/index.ts
+++ b/src/compile/render-dom/index.ts
@@ -395,11 +395,11 @@ export default function dom(
 		});
 
 		let unknown_props_check;
-		if (component.compile_options.dev && writable_props.length) {
+		if (component.compile_options.dev && !component.var_lookup.has('$$props') && writable_props.length) {
 			unknown_props_check = deindent`
 				const writable_props = [${writable_props.map(prop => `'${prop.export_name}'`).join(', ')}];
 				Object.keys($$props).forEach(key => {
-					if (!writable_props.includes(key)) console.warn(\`<${component.tag}> was created with unknown prop '\${key}'\`);
+					if (!writable_props.includes(key) && !key.startsWith('$$')) console.warn(\`<${component.tag}> was created with unknown prop '\${key}'\`);
 				});
 			`;
 		}
diff --git a/test/runtime/samples/dev-warning-unknown-props-with-$$props/Foo.svelte b/test/runtime/samples/dev-warning-unknown-props-with-$$props/Foo.svelte
new file mode 100644
index 0000000000..9e5c62339d
--- /dev/null
+++ b/test/runtime/samples/dev-warning-unknown-props-with-$$props/Foo.svelte
@@ -0,0 +1,7 @@
+<script>
+	export let foo = undefined;
+
+</script>
+
+<div>{foo}</div>
+<div>{JSON.stringify($$props)}</div>
diff --git a/test/runtime/samples/dev-warning-unknown-props-with-$$props/_config.js b/test/runtime/samples/dev-warning-unknown-props-with-$$props/_config.js
new file mode 100644
index 0000000000..62ad08624d
--- /dev/null
+++ b/test/runtime/samples/dev-warning-unknown-props-with-$$props/_config.js
@@ -0,0 +1,7 @@
+export default {
+	compileOptions: {
+		dev: true
+	},
+
+	warnings: []
+};
diff --git a/test/runtime/samples/dev-warning-unknown-props-with-$$props/main.svelte b/test/runtime/samples/dev-warning-unknown-props-with-$$props/main.svelte
new file mode 100644
index 0000000000..1566cf3e41
--- /dev/null
+++ b/test/runtime/samples/dev-warning-unknown-props-with-$$props/main.svelte
@@ -0,0 +1,5 @@
+<script>
+	import Foo from './Foo.svelte';
+</script>
+
+<Foo fo="sho"/>
diff --git a/test/runtime/samples/dev-warning-unknown-props-with-$$scope/Foo.svelte b/test/runtime/samples/dev-warning-unknown-props-with-$$scope/Foo.svelte
new file mode 100644
index 0000000000..b9f7feec24
--- /dev/null
+++ b/test/runtime/samples/dev-warning-unknown-props-with-$$scope/Foo.svelte
@@ -0,0 +1,6 @@
+<script>
+	export let answer;
+</script>
+
+<h1>{answer}</h1>
+<div><slot></slot></div>
diff --git a/test/runtime/samples/dev-warning-unknown-props-with-$$scope/_config.js b/test/runtime/samples/dev-warning-unknown-props-with-$$scope/_config.js
new file mode 100644
index 0000000000..62ad08624d
--- /dev/null
+++ b/test/runtime/samples/dev-warning-unknown-props-with-$$scope/_config.js
@@ -0,0 +1,7 @@
+export default {
+	compileOptions: {
+		dev: true
+	},
+
+	warnings: []
+};
diff --git a/test/runtime/samples/dev-warning-unknown-props-with-$$scope/main.svelte b/test/runtime/samples/dev-warning-unknown-props-with-$$scope/main.svelte
new file mode 100644
index 0000000000..a1656e86e0
--- /dev/null
+++ b/test/runtime/samples/dev-warning-unknown-props-with-$$scope/main.svelte
@@ -0,0 +1,7 @@
+<script>
+	import Foo from './Foo.svelte';
+</script>
+
+<Foo answer={42}>
+	bar
+</Foo>