diff --git a/packages/language-server/test/plugins/typescript/features/diagnostics/fixtures/generics-runes.v5/ValueComponent.svelte b/packages/language-server/test/plugins/typescript/features/diagnostics/fixtures/generics-runes.v5/ValueComponent.svelte
new file mode 100644
index 000000000..7d2dd5ebc
--- /dev/null
+++ b/packages/language-server/test/plugins/typescript/features/diagnostics/fixtures/generics-runes.v5/ValueComponent.svelte
@@ -0,0 +1,6 @@
+<script lang="ts" generics="T">
+    let { value, defaultValue }: { value: T; defaultValue?: T } = $props();
+</script>
+
+{value}
+{defaultValue}
\ No newline at end of file
diff --git a/packages/language-server/test/plugins/typescript/features/diagnostics/fixtures/generics-runes.v5/expectedv2.json b/packages/language-server/test/plugins/typescript/features/diagnostics/fixtures/generics-runes.v5/expectedv2.json
new file mode 100644
index 000000000..90f0fd771
--- /dev/null
+++ b/packages/language-server/test/plugins/typescript/features/diagnostics/fixtures/generics-runes.v5/expectedv2.json
@@ -0,0 +1,19 @@
+[
+    {
+        "code": 2322,
+        "message": "Type 'number' is not assignable to type 'string'.",
+        "range": {
+            "end": {
+                "character": 36,
+                "line": 10
+            },
+            "start": {
+                "character": 24,
+                "line": 10
+            }
+        },
+        "severity": 1,
+        "source": "ts",
+        "tags": []
+    }
+]
diff --git a/packages/language-server/test/plugins/typescript/features/diagnostics/fixtures/generics-runes.v5/input.svelte b/packages/language-server/test/plugins/typescript/features/diagnostics/fixtures/generics-runes.v5/input.svelte
new file mode 100644
index 000000000..d2442ff89
--- /dev/null
+++ b/packages/language-server/test/plugins/typescript/features/diagnostics/fixtures/generics-runes.v5/input.svelte
@@ -0,0 +1,11 @@
+<script lang="ts">
+    import ValueComponent from './ValueComponent.svelte';
+
+    let value = $state("test");
+</script>
+
+<!-- ok -->
+<ValueComponent {value} defaultValue={"foo"} />
+
+<!-- error -->
+<ValueComponent {value} defaultValue={1} />
\ No newline at end of file
diff --git a/packages/svelte2tsx/svelte-shims-v4.d.ts b/packages/svelte2tsx/svelte-shims-v4.d.ts
index 71bfbac6d..2d36a539d 100644
--- a/packages/svelte2tsx/svelte-shims-v4.d.ts
+++ b/packages/svelte2tsx/svelte-shims-v4.d.ts
@@ -207,7 +207,7 @@ declare type ATypedSvelteComponent = {
      */
     $$slot_def: any;
 
-    $on(event: string, handler: ((e: any) => any) | null | undefined): () => void;
+    $on(event: string, handler: any): () => void;
 }
 /**
  * Ambient type only used for intellisense, DO NOT USE IN YOUR PROJECT.