fix: compile typed catches and reject event loop syntax

packages/syntax/test/v060.test.ts

@@ -1,5 +1,5 @@
 import { expect, test } from "bun:test";
-import { diagnose, parse } from "../src/index.ts";
+import { diagnose, eraseFunctionTypes, parse } from "../src/index.ts";
 
 const source = `import type { PublicUser } from "@/types/user.ts"
 import PublicLayout from "@/layouts/PublicLayout.wrn"
@@ -118,3 +118,20 @@ test("readonly prop diagnostics still reject direct prop assignments", () => {
   }`);
   expect(diagnostics.some((diagnostic) => diagnostic.code === "WRN-PROP-READONLY")).toBe(true);
 });
+
+test("browser type erasure removes typed catch bindings", () => {
+  const source = `async function load(): Promise<void> {
+    try { await fetch("/api") } catch (error: any) { console.error(error) }
+  }`;
+  expect(eraseFunctionTypes(source)).toContain("catch (error)");
+  expect(eraseFunctionTypes(source)).not.toContain(": any");
+});
+
+test("diagnoses event syntax mistakenly used for loop directives", () => {
+  const diagnostics = diagnose(`component Rows {
+    view { <ul><li @for="row in rows" @key="row.id">{row.name}</li></ul> }
+  }`);
+  expect(diagnostics.filter((entry) => entry.code === "WRN-TEMPLATE-LOOP-DIRECTIVE")).toHaveLength(
+    2,
+  );
+});