From 0357428c339cf41b63c6570ef12e89af0d7307fe Mon Sep 17 00:00:00 2001
From: NullVoxPopuli-ai-agent
 <268630448+NullVoxPopuli-ai-agent@users.noreply.github.com>
Date: Tue, 25 Aug 2026 13:53:57 -0400
Subject: [PATCH] Keep the export default wrapper around a default-exported
 template

`export default <template>...</template>` spliced the GlimmerTemplate in
place of the whole ExportDefaultDeclaration, so the tree and `print()`
both lost the `export default`. The declaration is now what gets spliced.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FsXgxh6vNRWMCNcAQ3g6TN
---
 src/parse.js             | 22 ++++++++++++++++++----
 tests/parse.test.js      |  8 ++++++++
 tests/print-file.test.js |  5 +++++
 3 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/src/parse.js b/src/parse.js
index 4ce476c..f36a1f9 100644
--- a/src/parse.js
+++ b/src/parse.js
@@ -237,9 +237,25 @@ export function toTree(source, options = {}) {
   function walkWithKeys(node, parentPath) {
     if (!node || !node.type) return;
 
+    const path = { node, parent: parentPath?.node ?? null, parentPath };
+
     if (hasTemplates && PLACEHOLDER_TYPES.has(node.type)) {
       const parseResult = matchPlaceholder(node);
-      if (parseResult) {
+      if (parseResult && node.type === "ExportDefaultDeclaration") {
+        // `export default <template>...</template>`: keep the export wrapper
+        // and splice its declaration, so the tree (and `print`) still carry
+        // the `export default`.
+        const ast = processPlaceholder(parseResult, node.declaration);
+        node.declaration = ast;
+        setParent(ast, node);
+        if (hasVisitors && !seen.has(node)) {
+          seen.add(node);
+          const handler = visitors[node.type];
+          if (handler) handler(node, path);
+          walkWithKeys(ast, path);
+        }
+        return;
+      } else if (parseResult) {
         // Splice in place: write the GlimmerTemplate directly into the parent's
         // slot instead of allocating new ancestor objects. This preserves node
         // identity for every ancestor, which matters for WeakMap-keyed data
@@ -250,14 +266,12 @@ export function toTree(source, options = {}) {
         setParent(ast, parent);
         // Recurse into the Glimmer subtree so visitors fire on its nodes too.
         // The Glimmer root's parentPath reflects its true JS parent — the
-        // placeholder (UnaryExpression / StaticBlock) is an internal artifact.
+        // placeholder (`void` expression / StaticBlock) is an internal artifact.
         if (hasVisitors) walkWithKeys(ast, parentPath);
         return;
       }
     }
 
-    const path = { node, parent: parentPath?.node ?? null, parentPath };
-
     if (hasVisitors && !seen.has(node)) {
       seen.add(node);
       const handler = visitors[node.type];
diff --git a/tests/parse.test.js b/tests/parse.test.js
index cc37a64..a78419b 100644
--- a/tests/parse.test.js
+++ b/tests/parse.test.js
@@ -184,6 +184,14 @@ describe("parse", () => {
     ]);
   });
 
+  it("keeps the export default wrapper around a default-exported template", () => {
+    const source = `export default <template>hi</template>;\n`;
+    const ast = parse(source);
+
+    expect(ast.program.body.map((node) => node.type)).toEqual(["ExportDefaultDeclaration"]);
+    expect(ast.program.body[0].declaration.type).toBe("GlimmerTemplate");
+  });
+
   it("handles multiple classes with templates", () => {
     const source = `class A extends Component {
   <template><div>A</div></template>
diff --git a/tests/print-file.test.js b/tests/print-file.test.js
index a301f47..00031b0 100644
--- a/tests/print-file.test.js
+++ b/tests/print-file.test.js
@@ -11,6 +11,11 @@ describe("print(File)", () => {
     `);
   });
 
+  it("round-trips a default-exported template", () => {
+    const source = `export default <template>hi</template>;`;
+    expect(print(toTree(source))).toBe("export default <template>hi</template>");
+  });
+
   it("prints an empty File", () => {
     const tree = toTree(``, { filePath: "m.js" });