From 28d0ff02910e8e68dc3a2def74166aece71a4ba0 Mon Sep 17 00:00:00 2001
From: ZHAO Jinxiang <xiaoxiangmoe@gmail.com>
Date: Fri, 18 Mar 2022 20:37:57 +0800
Subject: [PATCH] Fix export default expression comment

---
 src/compiler/transformers/declarations.ts     |  3 +++
 .../exportDefaultExpressionComments.js        | 22 +++++++++++++++++++
 .../exportDefaultExpressionComments.symbols   |  7 ++++++
 .../exportDefaultExpressionComments.types     |  7 ++++++
 .../exportDefaultExpressionComments.ts        |  6 +++++
 5 files changed, 45 insertions(+)
 create mode 100644 tests/baselines/reference/exportDefaultExpressionComments.js
 create mode 100644 tests/baselines/reference/exportDefaultExpressionComments.symbols
 create mode 100644 tests/baselines/reference/exportDefaultExpressionComments.types
 create mode 100644 tests/cases/conformance/declarationEmit/exportDefaultExpressionComments.ts

diff --git a/src/compiler/transformers/declarations.ts b/src/compiler/transformers/declarations.ts
index eae56dbaf1ae8..37814d4e3f2e0 100644
--- a/src/compiler/transformers/declarations.ts
+++ b/src/compiler/transformers/declarations.ts
@@ -1140,6 +1140,9 @@ namespace ts {
                         const varDecl = factory.createVariableDeclaration(newId, /*exclamationToken*/ undefined, resolver.createTypeOfExpression(input.expression, input, declarationEmitNodeBuilderFlags, symbolTracker), /*initializer*/ undefined);
                         errorFallbackNode = undefined;
                         const statement = factory.createVariableStatement(needsDeclare ? [factory.createModifier(SyntaxKind.DeclareKeyword)] : [], factory.createVariableDeclarationList([varDecl], NodeFlags.Const));
+
+                        preserveJsDoc(statement, input);
+                        removeAllComments(input);
                         return [statement, factory.updateExportAssignment(input, input.decorators, input.modifiers, newId)];
                     }
                 }
diff --git a/tests/baselines/reference/exportDefaultExpressionComments.js b/tests/baselines/reference/exportDefaultExpressionComments.js
new file mode 100644
index 0000000000000..c3a9bb61da611
--- /dev/null
+++ b/tests/baselines/reference/exportDefaultExpressionComments.js
@@ -0,0 +1,22 @@
+//// [exportDefaultExpressionComments.ts]
+/**
+ * JSDoc Comments
+ */
+export default null
+
+
+//// [exportDefaultExpressionComments.js]
+"use strict";
+exports.__esModule = true;
+/**
+ * JSDoc Comments
+ */
+exports["default"] = null;
+
+
+//// [exportDefaultExpressionComments.d.ts]
+/**
+ * JSDoc Comments
+ */
+declare const _default: any;
+export default _default;
diff --git a/tests/baselines/reference/exportDefaultExpressionComments.symbols b/tests/baselines/reference/exportDefaultExpressionComments.symbols
new file mode 100644
index 0000000000000..a3a94331a56cd
--- /dev/null
+++ b/tests/baselines/reference/exportDefaultExpressionComments.symbols
@@ -0,0 +1,7 @@
+=== tests/cases/conformance/declarationEmit/exportDefaultExpressionComments.ts ===
+/**
+No type information for this code. * JSDoc Comments
+No type information for this code. */
+No type information for this code.export default null
+No type information for this code.
+No type information for this code.
\ No newline at end of file
diff --git a/tests/baselines/reference/exportDefaultExpressionComments.types b/tests/baselines/reference/exportDefaultExpressionComments.types
new file mode 100644
index 0000000000000..012b8d32555ff
--- /dev/null
+++ b/tests/baselines/reference/exportDefaultExpressionComments.types
@@ -0,0 +1,7 @@
+=== tests/cases/conformance/declarationEmit/exportDefaultExpressionComments.ts ===
+/**
+ * JSDoc Comments
+ */
+export default null
+>null : null
+
diff --git a/tests/cases/conformance/declarationEmit/exportDefaultExpressionComments.ts b/tests/cases/conformance/declarationEmit/exportDefaultExpressionComments.ts
new file mode 100644
index 0000000000000..a7477cc7557ab
--- /dev/null
+++ b/tests/cases/conformance/declarationEmit/exportDefaultExpressionComments.ts
@@ -0,0 +1,6 @@
+// @declaration: true
+
+/**
+ * JSDoc Comments
+ */
+export default null