fix instrumentation of auto-subscription self-assignments (#2681)

src/compile/render-dom/index.ts

@@ -182,7 +182,7 @@ export default function dom(
 
 					if (node.operator === '=' && nodes_match(node.left, node.right)) {
 						const dirty = names.filter(name => {
-							return scope.find_owner(name) === component.instance_scope;
+							return name[0] === '$' || scope.find_owner(name) === component.instance_scope;
 						});
 
 						if (dirty.length) component.has_reactive_assignments = true;

test/runtime/samples/instrumentation-auto-subscription-self-assignment/_config.js

@@ -0,0 +1,8 @@
+export default {
+	html: `[]`,
+
+	async test({ assert, component, target }) {
+		await component.go();
+		assert.htmlEqual(target.innerHTML, `[42]`);
+	}
+};

test/runtime/samples/instrumentation-auto-subscription-self-assignment/main.svelte

@@ -0,0 +1,11 @@
+<script>
+	import { writable } from 'svelte/store';
+	const foo = writable([]);
+	$: bar = $foo;
+	export function go() {
+		$foo.push(42);
+		$foo = $foo;
+	}
+</script>
+
+{JSON.stringify(bar)}