fix do not warn about missing props for bindings

src/compiler/compile/render_dom/index.ts

@@ -180,12 +180,14 @@ export default function dom(
 
 		if (expected.length) {
 			dev_props_check = b`
-				const { ctx: #ctx } = this.$$;
-				const props = ${options.customElement ? x`this.attributes` : x`options.props || {}`};
-				${expected.map(prop => b`
-				if (${renderer.reference(prop.name)} === undefined && !('${prop.export_name}' in props)) {
-					@_console.warn("<${component.tag}> was created without expected prop '${prop.export_name}'");
-				}`)}
+				const { ctx: #ctx, on_mount: #on_mount, bound: #bound, props: #props } = this.$$;
+				#on_mount.push(function () {
+					const props = ${options.customElement ? x`this.attributes` : x`options.props || {}`};
+					${expected.map(prop => b`
+					if (${renderer.reference(prop.name)} === undefined && !('${prop.export_name}' in props || #bound[#props['${prop.export_name}']])) {
+						@_console.warn("<${component.tag}> was created without expected prop '${prop.export_name}'");
+					}`)}
+				});
 			`;
 		}
 

test/runtime/samples/dev-warning-missing-data-component-bind/Foo.svelte

@@ -0,0 +1,8 @@
+<script>
+	export let w;
+	export let x;
+	export let y;
+	export let z = undefined;
+</script>
+
+<div>{w} {x} {y}</div>

test/runtime/samples/dev-warning-missing-data-component-bind/_config.js

@@ -0,0 +1,9 @@
+export default {
+	compileOptions: {
+		dev: true
+	},
+
+	warnings: [
+		"<Foo> was created without expected prop 'y'"
+	]
+};

test/runtime/samples/dev-warning-missing-data-component-bind/main.svelte

@@ -0,0 +1,8 @@
+<script>
+	import Foo from './Foo.svelte';
+
+	let x = undefined;
+	let w = 'w';
+</script>
+
+<Foo bind:w bind:x />