diff --git a/src/compiler/compile/render_dom/wrappers/shared/create_debugging_comment.ts b/src/compiler/compile/render_dom/wrappers/shared/create_debugging_comment.ts
index 1bdc473df0db..6e295f99c125 100644
--- a/src/compiler/compile/render_dom/wrappers/shared/create_debugging_comment.ts
+++ b/src/compiler/compile/render_dom/wrappers/shared/create_debugging_comment.ts
@@ -29,7 +29,7 @@ export default function create_debugging_comment(
 	} else {
 		// @ts-ignore
 		d = node.expression ? node.expression.node.end : c;
-		while (source[d] !== '}') d += 1;
+		while (source[d] !== '}' && d <= source.length) d += 1;
 		while (source[d] === '}') d += 1;
 	}
 
diff --git a/test/runtime/samples/component-slot-slot/Component.svelte b/test/runtime/samples/component-slot-slot/Component.svelte
new file mode 100644
index 000000000000..fdcb8e7f2b7d
--- /dev/null
+++ b/test/runtime/samples/component-slot-slot/Component.svelte
@@ -0,0 +1,3 @@
+<div>
+	<slot name="test" />
+</div>
diff --git a/test/runtime/samples/component-slot-slot/Forward.svelte b/test/runtime/samples/component-slot-slot/Forward.svelte
new file mode 100644
index 000000000000..320be9df2506
--- /dev/null
+++ b/test/runtime/samples/component-slot-slot/Forward.svelte
@@ -0,0 +1,7 @@
+<script>
+	import Component from './Component.svelte';
+</script>
+
+<Component>
+	<slot slot="test" />
+</Component>
diff --git a/test/runtime/samples/component-slot-slot/_config.js b/test/runtime/samples/component-slot-slot/_config.js
new file mode 100644
index 000000000000..32af774fac2a
--- /dev/null
+++ b/test/runtime/samples/component-slot-slot/_config.js
@@ -0,0 +1,3 @@
+export default {
+	html: '<div><span>lol</span></div>'
+};
diff --git a/test/runtime/samples/component-slot-slot/main.svelte b/test/runtime/samples/component-slot-slot/main.svelte
new file mode 100644
index 000000000000..1718494b16dc
--- /dev/null
+++ b/test/runtime/samples/component-slot-slot/main.svelte
@@ -0,0 +1,9 @@
+<script>
+	import Forward from './Forward.svelte';
+</script>
+
+<Forward>
+	<span>
+		lol
+	</span>
+</Forward>