Emit comments on system export default expressions on the surrounding export call epxression instead (microsoft#17970)

weswigham · web-flow · commit 72884b8f27ab · 2017-09-06T21:59:06.000-07:00
diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
@@ -2519,7 +2519,7 @@ namespace ts {
                 //          2
                 //          /* end of element 2 */
                 //       ];
-                if (previousSibling && delimiter && previousSibling.end !== parentNode.end) {
+                if (previousSibling && delimiter && previousSibling.end !== parentNode.end && !(getEmitFlags(previousSibling) & EmitFlags.NoTrailingComments)) {
                     emitLeadingCommentsOfPosition(previousSibling.end);
                 }
 
diff --git a/src/compiler/transformers/module/system.ts b/src/compiler/transformers/module/system.ts
@@ -1132,7 +1132,8 @@ namespace ts {
          */
         function createExportExpression(name: Identifier | StringLiteral, value: Expression) {
             const exportName = isIdentifier(name) ? createLiteral(name) : name;
-            return createCall(exportFunction, /*typeArguments*/ undefined, [exportName, value]);
+            setEmitFlags(value, getEmitFlags(value) | EmitFlags.NoComments);
+            return setCommentRange(createCall(exportFunction, /*typeArguments*/ undefined, [exportName, value]), value);
         }
 
         //
diff --git a/tests/baselines/reference/systemDefaultExportCommentValidity.js b/tests/baselines/reference/systemDefaultExportCommentValidity.js
@@ -0,0 +1,20 @@
+//// [systemDefaultExportCommentValidity.ts]
+const Home = {}
+
+export default Home
+// There is intentionally no semicolon on the prior line, this comment should not break emit
+
+//// [systemDefaultExportCommentValidity.js]
+System.register([], function (exports_1, context_1) {
+    "use strict";
+    var __moduleName = context_1 && context_1.id;
+    var Home;
+    return {
+        setters: [],
+        execute: function () {
+            Home = {};
+            exports_1("default", Home);
+            // There is intentionally no semicolon on the prior line, this comment should not break emit 
+        }
+    };
+});
diff --git a/tests/baselines/reference/systemDefaultExportCommentValidity.symbols b/tests/baselines/reference/systemDefaultExportCommentValidity.symbols
@@ -0,0 +1,8 @@
+=== tests/cases/compiler/systemDefaultExportCommentValidity.ts ===
+const Home = {}
+>Home : Symbol(Home, Decl(systemDefaultExportCommentValidity.ts, 0, 5))
+
+export default Home
+>Home : Symbol(Home, Decl(systemDefaultExportCommentValidity.ts, 0, 5))
+
+// There is intentionally no semicolon on the prior line, this comment should not break emit
diff --git a/tests/baselines/reference/systemDefaultExportCommentValidity.types b/tests/baselines/reference/systemDefaultExportCommentValidity.types
@@ -0,0 +1,9 @@
+=== tests/cases/compiler/systemDefaultExportCommentValidity.ts ===
+const Home = {}
+>Home : {}
+>{} : {}
+
+export default Home
+>Home : {}
+
+// There is intentionally no semicolon on the prior line, this comment should not break emit
diff --git a/tests/cases/compiler/systemDefaultExportCommentValidity.ts b/tests/cases/compiler/systemDefaultExportCommentValidity.ts
@@ -0,0 +1,5 @@
+// @module: system
+const Home = {}
+
+export default Home
+// There is intentionally no semicolon on the prior line, this comment should not break emit

Original file line number	Diff line number	Diff line change
`@@ -2519,7 +2519,7 @@ namespace ts {`
`2519`	`2519`	`// 2`
`2520`	`2520`	`// /* end of element 2 */`
`2521`	`2521`	`// ];`
`2522`		`- if (previousSibling && delimiter && previousSibling.end !== parentNode.end) {`
	`2522`	`+ if (previousSibling && delimiter && previousSibling.end !== parentNode.end && !(getEmitFlags(previousSibling) & EmitFlags.NoTrailingComments)) {`
`2523`	`2523`	`emitLeadingCommentsOfPosition(previousSibling.end);`
`2524`	`2524`	`}`
`2525`	`2525`
Original file line number	Diff line number	Diff line change
`@@ -1132,7 +1132,8 @@ namespace ts {`
`1132`	`1132`	`*/`
`1133`	`1133`	`function createExportExpression(name: Identifier \| StringLiteral, value: Expression) {`
`1134`	`1134`	`const exportName = isIdentifier(name) ? createLiteral(name) : name;`
`1135`		`- return createCall(exportFunction, /typeArguments/ undefined, [exportName, value]);`
	`1135`	`+ setEmitFlags(value, getEmitFlags(value) \| EmitFlags.NoComments);`
	`1136`	`+ return setCommentRange(createCall(exportFunction, /typeArguments/ undefined, [exportName, value]), value);`
`1136`	`1137`	`}`
`1137`	`1138`
`1138`	`1139`	`//`