feat: treated facade default export ref as never get reassigned (roll…

…down#2966)

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### Description

<!-- Please insert your description here and provide especially info
about the "what" this PR is solving -->

crates/rolldown/src/ast_scanner/mod.rs

@@ -117,6 +117,9 @@ impl<'me, 'ast: 'me> AstScanner<'me, 'ast> {
     let legitimized_repr_name = legitimize_identifier_name(repr_name);
     let default_export_ref = symbol_ref_db
       .create_facade_root_symbol_ref(concat_string!(legitimized_repr_name, "_default").into());
+    // This is used for converting "export default foo;" => "var [default_export_ref] = foo;"
+    // And we consider [default_export_ref] never get reassigned.
+    default_export_ref.flags_mut(&mut symbol_ref_db).insert(SymbolRefFlags::IS_NOT_REASSIGNED);
 
     let name = concat_string!(legitimized_repr_name, "_exports");
     let namespace_object_ref = symbol_ref_db.create_facade_root_symbol_ref(name.into());

crates/rolldown/tests/esbuild/default/export_forms_iife/artifacts.snap

@@ -1,5 +1,6 @@
 ---
 source: crates/rolldown_testing/src/integration_test.rs
+snapshot_kind: text
 ---
 # warnings
 
@@ -50,12 +51,7 @@ Object.defineProperty(exports, 'b', {
   }
 });
 exports.c = c
-Object.defineProperty(exports, 'default', {
-  enumerable: true,
-  get: function () {
-    return entry_default;
-  }
-});
+exports.default = entry_default
 exports.l = l
 exports.v = v
 return exports;

crates/rolldown/tests/esbuild/default/export_forms_iife/bypass.md

@@ -80,12 +80,7 @@ Object.defineProperty(exports, 'b', {
   }
 });
 exports.c = c
-Object.defineProperty(exports, 'default', {
-  enumerable: true,
-  get: function () {
-    return entry_default;
-  }
-});
+exports.default = entry_default
 exports.l = l
 exports.v = v
 return exports;
@@ -96,7 +91,7 @@ return exports;
 ===================================================================
 --- esbuild	/out.js
 +++ rolldown	entry.js
-@@ -1,27 +1,37 @@
+@@ -1,27 +1,32 @@
 -var globalName = (() => {
 -    var entry_exports = {};
 -    __export(entry_exports, {
@@ -142,12 +137,7 @@ return exports;
 +        }
 +    });
 +    exports.c = c;
-+    Object.defineProperty(exports, 'default', {
-+        enumerable: true,
-+        get: function () {
-+            return entry_default;
-+        }
-+    });
++    exports.default = entry_default;
 +    exports.l = l;
 +    exports.v = v;
 +    return exports;

crates/rolldown/tests/rolldown/function/es_module/if_default_prop_cjs_true/artifacts.snap

@@ -1,5 +1,6 @@
 ---
 source: crates/rolldown_testing/src/integration_test.rs
+snapshot_kind: text
 ---
 # Assets
 
@@ -14,11 +15,6 @@ var main_default = "if_default_prop_true";
 const value = true;
 
 //#endregion
-Object.defineProperty(exports, 'default', {
-  enumerable: true,
-  get: function () {
-    return main_default;
-  }
-});
+exports.default = main_default
 exports.value = value
 ```

crates/rolldown/tests/rolldown/function/es_module/if_default_prop_iife_true/artifacts.snap

@@ -1,5 +1,6 @@
 ---
 source: crates/rolldown_testing/src/integration_test.rs
+snapshot_kind: text
 ---
 # Assets
 
@@ -16,12 +17,7 @@ var main_default = "if_default_prop_true";
 const value = true;
 
 //#endregion
-Object.defineProperty(exports, 'default', {
-  enumerable: true,
-  get: function () {
-    return main_default;
-  }
-});
+exports.default = main_default
 exports.value = value
 return exports;
 })({});

crates/rolldown/tests/rolldown/function/export_mode/cjs/named/artifacts.snap

@@ -1,5 +1,6 @@
 ---
 source: crates/rolldown_testing/src/integration_test.rs
+snapshot_kind: text
 ---
 # Assets
 
@@ -23,10 +24,5 @@ var main_default = example();
 
 //#endregion
 exports.a = a
-Object.defineProperty(exports, 'default', {
-  enumerable: true,
-  get: function () {
-    return main_default;
-  }
-});
+exports.default = main_default
 ```

crates/rolldown/tests/rolldown/topics/cjs_module_lexer_compat/exports/artifacts.snap

@@ -1,5 +1,6 @@
 ---
 source: crates/rolldown_testing/src/integration_test.rs
+snapshot_kind: text
 ---
 # Assets
 
@@ -18,11 +19,6 @@ var main_default = "default";
 //#endregion
 exports.a = a
 exports.b = b
-Object.defineProperty(exports, 'default', {
-  enumerable: true,
-  get: function () {
-    return main_default;
-  }
-});
+exports.default = main_default
 exports["😈"] = devil
 ```

crates/rolldown/tests/rolldown/topics/live_bindings/default_export_expr_cjs/artifacts.snap

@@ -1,5 +1,6 @@
 ---
 source: crates/rolldown_testing/src/integration_test.rs
+snapshot_kind: text
 ---
 # Assets
 
@@ -20,12 +21,7 @@ function inc() {
 var main_default = count;
 
 //#endregion
-Object.defineProperty(exports, 'default', {
-  enumerable: true,
-  get: function () {
-    return main_default;
-  }
-});
+exports.default = main_default
 exports.inc = inc
 exports.reset = reset
 ```

crates/rolldown/tests/rolldown/topics/preserve_semantic_of_entries_exports/named_export_cjs/artifacts.snap

@@ -1,5 +1,6 @@
 ---
 source: crates/rolldown_testing/src/integration_test.rs
+snapshot_kind: text
 ---
 # Assets
 
@@ -14,11 +15,6 @@ const foo = "foo";
 var main_default = "main";
 
 //#endregion
-Object.defineProperty(exports, 'default', {
-  enumerable: true,
-  get: function () {
-    return main_default;
-  }
-});
+exports.default = main_default
 exports.foo = foo
 ```

crates/rolldown/tests/rolldown/topics/preserve_semantic_of_entries_exports/named_export_in_shared_entries_cjs/artifacts.snap

@@ -9,25 +9,15 @@ snapshot_kind: text
 ```js
 const require_main = require('./main.js');
 
-Object.defineProperty(exports, 'default', {
-  enumerable: true,
-  get: function () {
-    return require_main.main_default;
-  }
-});
+exports.default = require_main.main_default
 exports.foo = require_main.foo
 ```
 ## entry2.js
 
 ```js
 const require_main = require('./main.js');
 
-Object.defineProperty(exports, 'default', {
-  enumerable: true,
-  get: function () {
-    return require_main.main_default;
-  }
-});
+exports.default = require_main.main_default
 exports.foo = require_main.foo
 ```
 ## main.js

crates/rolldown/tests/rolldown/topics/preserve_semantic_of_entries_exports/named_export_in_wrapped_cjs/artifacts.snap

@@ -1,5 +1,6 @@
 ---
 source: crates/rolldown_testing/src/integration_test.rs
+snapshot_kind: text
 ---
 # Assets
 
@@ -25,11 +26,6 @@ var init_main = __esm({ "main.js"() {
 
 //#endregion
 init_main();
-Object.defineProperty(exports, 'default', {
-  enumerable: true,
-  get: function () {
-    return main_default;
-  }
-});
+exports.default = main_default
 exports.foo = foo
 ```

crates/rolldown/tests/rolldown/warnings/mixed_export/artifacts.snap

@@ -1,5 +1,6 @@
 ---
 source: crates/rolldown_testing/src/integration_test.rs
+snapshot_kind: text
 ---
 # warnings
 
@@ -25,12 +26,7 @@ const a = 2;
 
 //#endregion
 exports.a = a
-Object.defineProperty(exports, 'default', {
-  enumerable: true,
-  get: function () {
-    return main_default;
-  }
-});
+exports.default = main_default
 return exports;
 })({});
 ```

crates/rolldown/tests/snapshots/integration_rolldown__filename_with_hash.snap

@@ -798,7 +798,7 @@ snapshot_kind: text
 
 # tests/esbuild/default/export_forms_iife
 
-- entry-!~{000}~.js => entry-B6vlME3I.js
+- entry-!~{000}~.js => entry-BA-K-SNR.js
 
 # tests/esbuild/default/export_forms_with_minify_identifiers_and_no_bundle
 
@@ -3935,15 +3935,15 @@ snapshot_kind: text
 
 # tests/rolldown/function/es_module/if_default_prop_cjs_true
 
-- main-!~{000}~.js => main-CsgEFrlH.js
+- main-!~{000}~.js => main-cgJDF9TZ.js
 
 # tests/rolldown/function/es_module/if_default_prop_iife_false
 
 - main-!~{000}~.js => main-B_AS4TD4.js
 
 # tests/rolldown/function/es_module/if_default_prop_iife_true
 
-- main-!~{000}~.js => main-IwFiE4Ff.js
+- main-!~{000}~.js => main-D9LdNfYj.js
 
 # tests/rolldown/function/es_module/never
 
@@ -3995,7 +3995,7 @@ snapshot_kind: text
 
 # tests/rolldown/function/export_mode/cjs/named
 
-- main-!~{000}~.js => main-B0d7SG5w.js
+- main-!~{000}~.js => main-BwzQ9T-O.js
 
 # tests/rolldown/function/export_mode/iife/auto/none
 
@@ -4939,7 +4939,7 @@ snapshot_kind: text
 
 # tests/rolldown/topics/cjs_module_lexer_compat/exports
 
-- main-!~{000}~.js => main-C_LhPujj.js
+- main-!~{000}~.js => main-ncpt5xmU.js
 
 # tests/rolldown/topics/css/align_vite
 
@@ -5043,7 +5043,7 @@ snapshot_kind: text
 
 # tests/rolldown/topics/live_bindings/default_export_expr_cjs
 
-- main-!~{000}~.js => main-DURgDUYH.js
+- main-!~{000}~.js => main-B_iLbtpg.js
 
 # tests/rolldown/topics/live_bindings/default_export_expr_in_common_chunks
 
@@ -5117,7 +5117,7 @@ snapshot_kind: text
 
 # tests/rolldown/topics/preserve_semantic_of_entries_exports/named_export_cjs
 
-- main-!~{000}~.js => main-Cmb9Qu4e.js
+- main-!~{000}~.js => main-SgusirFn.js
 
 # tests/rolldown/topics/preserve_semantic_of_entries_exports/named_export_in_shared_entries
 
@@ -5127,8 +5127,8 @@ snapshot_kind: text
 
 # tests/rolldown/topics/preserve_semantic_of_entries_exports/named_export_in_shared_entries_cjs
 
-- entry-!~{000}~.js => entry-D8lyh8F8.js
-- entry2-!~{001}~.js => entry2-CoQWESLQ.js
+- entry-!~{000}~.js => entry-DSxxgWLd.js
+- entry2-!~{001}~.js => entry2-CXxnJInr.js
 - main-!~{002}~.js => main-DallkI37.js
 
 # tests/rolldown/topics/preserve_semantic_of_entries_exports/named_export_in_wrapped
@@ -5143,7 +5143,7 @@ snapshot_kind: text
 
 # tests/rolldown/topics/preserve_semantic_of_entries_exports/named_export_in_wrapped_cjs
 
-- main-!~{000}~.js => main-D4BrWgkl.js
+- main-!~{000}~.js => main-BfW_etaZ.js
 
 # tests/rolldown/tree_shaking/advanced_barrel_exports
 
@@ -5268,7 +5268,7 @@ snapshot_kind: text
 
 # tests/rolldown/warnings/mixed_export
 
-- main-!~{000}~.js => main-BO4-4DlB.js
+- main-!~{000}~.js => main-BMoXN5sO.js
 
 # tests/rolldown/warnings/none-ascii-content
 

packages/rolldown/tests/fixtures/output/format/iife/exports/_config.ts

@@ -44,12 +44,7 @@ export default defineTest({
       var main_default = node_path.join;
 
       //#endregion
-      Object.defineProperty(exports, 'default', {
-        enumerable: true,
-        get: function () {
-          return main_default;
-        }
-      });
+      exports.default = main_default
       return exports;
       })({}, node_path);"
     `)