diff --git a/src/compile/nodes/shared/Expression.ts b/src/compile/nodes/shared/Expression.ts
index e97cc610fa..30c6ccbc34 100644
--- a/src/compile/nodes/shared/Expression.ts
+++ b/src/compile/nodes/shared/Expression.ts
@@ -377,6 +377,7 @@ export default class Expression {
 							code.appendLeft(node.end, `; ${insert}`);
 						}
 
+						component.has_reactive_assignments = true;
 						pending_assignments = new Set();
 					}
 				}
diff --git a/src/utils/annotateWithScopes.ts b/src/utils/annotateWithScopes.ts
index 0ea4f60068..96459e1ede 100644
--- a/src/utils/annotateWithScopes.ts
+++ b/src/utils/annotateWithScopes.ts
@@ -30,7 +30,7 @@ export function createScopes(expression: Node) {
 						scope.declarations.set(name, node);
 					});
 				});
-			} else if (/For(?:In|Of)Statement/.test(node.type)) {
+			} else if (/For(?:In|Of)?Statement/.test(node.type)) {
 				scope = new Scope(scope, true);
 				map.set(node, scope);
 			} else if (node.type === 'BlockStatement') {
diff --git a/test/runtime/samples/instrumentation-script-loop-scope/_config.js b/test/runtime/samples/instrumentation-script-loop-scope/_config.js
new file mode 100644
index 0000000000..1195055c45
--- /dev/null
+++ b/test/runtime/samples/instrumentation-script-loop-scope/_config.js
@@ -0,0 +1,17 @@
+export default {
+	html: `
+		<button>foo</button>
+		<p>x: 0</p>
+	`,
+
+	async test({ assert, component, target, window }) {
+		const buttons = target.querySelectorAll('button');
+		const click = new window.MouseEvent('click');
+
+		await buttons[0].dispatchEvent(click);
+		assert.htmlEqual(target.innerHTML, `
+			<button>foo</button>
+			<p>x: 42</p>
+		`);
+	}
+};
\ No newline at end of file
diff --git a/test/runtime/samples/instrumentation-script-loop-scope/main.html b/test/runtime/samples/instrumentation-script-loop-scope/main.html
new file mode 100644
index 0000000000..d2ca75a82d
--- /dev/null
+++ b/test/runtime/samples/instrumentation-script-loop-scope/main.html
@@ -0,0 +1,14 @@
+<script>
+	let x = 0;
+
+	function foo() {
+		(() => {
+			for (let x = 0; x < 10; x++) {}
+			x = 42;
+		})();
+	}
+</script>
+
+<button on:click={foo}>foo</button>
+
+<p>x: {x}</p>
\ No newline at end of file
diff --git a/test/runtime/samples/instrumentation-template-loop-scope/_config.js b/test/runtime/samples/instrumentation-template-loop-scope/_config.js
new file mode 100644
index 0000000000..a2726934be
--- /dev/null
+++ b/test/runtime/samples/instrumentation-template-loop-scope/_config.js
@@ -0,0 +1,21 @@
+export default {
+	html: `
+		<button>foo</button>
+		<button>bar</button>
+
+		<p>x: 0</p>
+	`,
+
+	async test({ assert, component, target, window }) {
+		const buttons = target.querySelectorAll('button');
+		const click = new window.MouseEvent('click');
+
+		await buttons[0].dispatchEvent(click);
+		assert.htmlEqual(target.innerHTML, `
+			<button>foo</button>
+			<button>bar</button>
+
+			<p>x: 42</p>
+		`);
+	}
+};
\ No newline at end of file
diff --git a/test/runtime/samples/instrumentation-template-loop-scope/main.html b/test/runtime/samples/instrumentation-template-loop-scope/main.html
new file mode 100644
index 0000000000..6032067ff0
--- /dev/null
+++ b/test/runtime/samples/instrumentation-template-loop-scope/main.html
@@ -0,0 +1,12 @@
+<script>
+	let x = 0;
+</script>
+
+<button on:click="{() => {
+	(() => {
+		for (let x = 0; x < 10; x++) {}
+		x = 42;
+	})();
+}}">foo</button>
+
+<p>x: {x}</p>
\ No newline at end of file