fix compiler hanging on <slot slot="..."> (#5536)

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;
 	}
 

test/runtime/samples/component-slot-slot/Component.svelte

@@ -0,0 +1,3 @@
+<div>
+	<slot name="test" />
+</div>

test/runtime/samples/component-slot-slot/Forward.svelte

@@ -0,0 +1,7 @@
+<script>
+	import Component from './Component.svelte';
+</script>
+
+<Component>
+	<slot slot="test" />
+</Component>

test/runtime/samples/component-slot-slot/_config.js

@@ -0,0 +1,3 @@
+export default {
+	html: '<div><span>lol</span></div>'
+};

test/runtime/samples/component-slot-slot/main.svelte

@@ -0,0 +1,9 @@
+<script>
+	import Forward from './Forward.svelte';
+</script>
+
+<Forward>
+	<span>
+		lol
+	</span>
+</Forward>