fix contextual dynamic bind:this in {#each} (#4759)

src/compiler/compile/render_dom/wrappers/shared/bind_this.ts

@@ -55,6 +55,9 @@ export default function bind_this(component: Component, block: Block, binding: B
 		const args = [];
 		for (const id of contextual_dependencies) {
 			args.push(id);
+			if (block.variables.has(id.name)) {
+				if (block.renderer.context_lookup.get(id.name).is_contextual) continue;
+			}
 			block.add_variable(id, block.renderer.reference(id.name));
 		}
 

test/runtime/samples/binding-this-each-object-props/_config.js

@@ -0,0 +1,14 @@
+export default {
+	html: ``,
+
+	async test({ assert, component, target }) {
+		component.visible = true;
+		assert.htmlEqual(target.innerHTML, `
+			<div>b</div><div>b</div><div>c</div><div>c</div>
+		`);
+		assert.equal(component.items1[1], target.querySelector('div'));
+		assert.equal(component.items2[1], target.querySelector('div:nth-child(2)'));
+		assert.equal(component.items1[2], target.querySelector('div:nth-child(3)'));
+		assert.equal(component.items2[2], target.querySelector('div:last-child'));
+	}
+};

test/runtime/samples/binding-this-each-object-props/main.svelte

@@ -0,0 +1,13 @@
+<script>
+	export const items1 = {};
+	export const items2 = {};
+	export let data = [
+		{id: 1, text: "b"},
+		{id: 2, text: "c"},
+	];
+</script>
+
+{#each data as item (item.id)}
+	<div bind:this={items1[item.id]}>{item.text}</div>
+	<div bind:this={items2[item.id]}>{item.text}</div>
+{/each}

test/runtime/samples/binding-this-each-object-spread/_config.js

@@ -0,0 +1,14 @@
+export default {
+	html: ``,
+
+	async test({ assert, component, target }) {
+		component.visible = true;
+		assert.htmlEqual(target.innerHTML, `
+			<div>a</div><div>a</div><div>b</div><div>b</div>
+		`);
+		assert.equal(component.items1[1], target.querySelector('div'));
+		assert.equal(component.items2[1], target.querySelector('div:nth-child(2)'));
+		assert.equal(component.items1[2], target.querySelector('div:nth-child(3)'));
+		assert.equal(component.items2[2], target.querySelector('div:last-child'));
+	}
+};

test/runtime/samples/binding-this-each-object-spread/main.svelte

@@ -0,0 +1,13 @@
+<script>
+	export const items1 = {};
+	export const items2 = {};
+	var data = [
+		{id: 1, text: "a"},
+		{id: 2, text: "b"},
+	];
+</script>
+
+{#each data as {id, text} (id)}
+	<div bind:this={items1[id]}>{text}</div>
+	<div bind:this={items2[id]}>{text}</div>
+{/each}