Only emit comment only once in module declaration with identifier path name

Author: Kanchalai Tanglertsampan

src/compiler/transformers/ts.ts

@@ -2859,7 +2859,6 @@ namespace ts {
                 const moduleBlock = <ModuleBlock>getInnerMostModuleDeclarationFromDottedModule(node).body;
                 statementsLocation = moveRangePos(moduleBlock.statements, -1);
             }
-
             addRange(statements, endLexicalEnvironment());
 
             currentNamespaceContainerName = savedCurrentNamespaceContainerName;
@@ -2872,6 +2871,30 @@ namespace ts {
                 /*location*/ blockLocation,
                 /*multiLine*/ true
             );
+
+            // namespace hello.hi.world {
+            //      function foo() {}
+            //
+            //      // TODO, blah
+            // }
+            //
+            // should be emitted as
+            //
+            // var hello;
+            // (function (hello) {
+            //     var hi;
+            //     (function (hi) {
+            //         var world;
+            //         (function (world) {
+            //             function foo() { }
+            //             // TODO, blah
+            //         })(world = hi.world || (hi.world = {}));
+            //     })(hi = hello.hi || (hello.hi = {}));
+            // })(hello || (hello = {}));
+            // so if the block is a transformed module declaration, turn off the comment emit
+            if (body.kind !== SyntaxKind.ModuleBlock) {
+                setNodeEmitFlags(block, block.emitFlags | NodeEmitFlags.NoComments);
+            }
             return block;
         }
 

tests/baselines/reference/commentInNamespaceDeclarationWithIdentifierPathName.js

@@ -0,0 +1,20 @@
+//// [commentInNamespaceDeclarationWithIdentifierPathName.ts]
+namespace hello.hi.world
+{
+    function foo() {}
+
+    // TODO, blah
+}
+
+//// [commentInNamespaceDeclarationWithIdentifierPathName.js]
+var hello;
+(function (hello) {
+    var hi;
+    (function (hi) {
+        var world;
+        (function (world) {
+            function foo() { }
+            // TODO, blah
+        })(world = hi.world || (hi.world = {}));
+    })(hi = hello.hi || (hello.hi = {}));
+})(hello || (hello = {}));

tests/baselines/reference/commentInNamespaceDeclarationWithIdentifierPathName.symbols

@@ -0,0 +1,11 @@
+=== tests/cases/compiler/commentInNamespaceDeclarationWithIdentifierPathName.ts ===
+namespace hello.hi.world
+>hello : Symbol(hello, Decl(commentInNamespaceDeclarationWithIdentifierPathName.ts, 0, 0))
+>hi : Symbol(hi, Decl(commentInNamespaceDeclarationWithIdentifierPathName.ts, 0, 16))
+>world : Symbol(world, Decl(commentInNamespaceDeclarationWithIdentifierPathName.ts, 0, 19))
+{
+    function foo() {}
+>foo : Symbol(foo, Decl(commentInNamespaceDeclarationWithIdentifierPathName.ts, 1, 1))
+
+    // TODO, blah
+}

tests/baselines/reference/commentInNamespaceDeclarationWithIdentifierPathName.types

@@ -0,0 +1,11 @@
+=== tests/cases/compiler/commentInNamespaceDeclarationWithIdentifierPathName.ts ===
+namespace hello.hi.world
+>hello : typeof hello
+>hi : typeof hi
+>world : typeof world
+{
+    function foo() {}
+>foo : () => void
+
+    // TODO, blah
+}

tests/cases/compiler/commentInNamespaceDeclarationWithIdentifierPathName.ts

@@ -0,0 +1,6 @@
+namespace hello.hi.world
+{
+    function foo() {}
+
+    // TODO, blah
+}