Retain comments inside return statements (microsoft#17557)

weswigham · web-flow · commit c399230767a4 · 2017-08-08T19:53:53.000-07:00
* Retain comments inside return statements by including the return keyword in the parse tree * Revert "Retain comments inside return statements by including the return keyword in the parse tree" This reverts commit 5d2142e. * Readd test * Function for handling printing comments on a token
diff --git a/src/compiler/comments.ts b/src/compiler/comments.ts
@@ -8,7 +8,7 @@ namespace ts {
         setWriter(writer: EmitTextWriter): void;
         emitNodeWithComments(hint: EmitHint, node: Node, emitCallback: (hint: EmitHint, node: Node) => void): void;
         emitBodyWithDetachedComments(node: Node, detachedRange: TextRange, emitCallback: (node: Node) => void): void;
-        emitTrailingCommentsOfPosition(pos: number): void;
+        emitTrailingCommentsOfPosition(pos: number, prefixSpace?: boolean): void;
         emitLeadingCommentsOfPosition(pos: number): void;
     }
 
@@ -306,7 +306,7 @@ namespace ts {
             }
         }
 
-        function emitTrailingCommentsOfPosition(pos: number) {
+        function emitTrailingCommentsOfPosition(pos: number, prefixSpace?: boolean) {
             if (disabled) {
                 return;
             }
@@ -315,7 +315,7 @@ namespace ts {
                 performance.mark("beforeEmitTrailingCommentsOfPosition");
             }
 
-            forEachTrailingCommentToEmit(pos, emitTrailingCommentOfPosition);
+            forEachTrailingCommentToEmit(pos, prefixSpace ? emitTrailingComment : emitTrailingCommentOfPosition);
 
             if (extendedDiagnostics) {
                 performance.measure("commentTime", "beforeEmitTrailingCommentsOfPosition");
diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
@@ -1572,8 +1572,20 @@ namespace ts {
             write(";");
         }
 
+        function emitTokenWithComment(token: SyntaxKind, pos: number, contextNode?: Node) {
+            const node = contextNode && getParseTreeNode(contextNode);
+            if (node && node.kind === contextNode.kind) {
+                pos = skipTrivia(currentSourceFile.text, pos);
+            }
+            pos = writeToken(token, pos, /*contextNode*/ contextNode);
+            if (node && node.kind === contextNode.kind) {
+                emitTrailingCommentsOfPosition(pos, /*prefixSpace*/ true);
+            }
+            return pos;
+        }
+
         function emitReturnStatement(node: ReturnStatement) {
-            writeToken(SyntaxKind.ReturnKeyword, node.pos, /*contextNode*/ node);
+            emitTokenWithComment(SyntaxKind.ReturnKeyword, node.pos, /*contextNode*/ node);
             emitExpressionWithPrefix(" ", node.expression);
             write(";");
         }
diff --git a/tests/baselines/reference/jsdocCastCommentEmit.js b/tests/baselines/reference/jsdocCastCommentEmit.js
@@ -0,0 +1,17 @@
+//// [jsdocCastCommentEmit.ts]
+// allowJs: true
+// checkJs: true
+// outDir: out/
+// filename: input.js
+function f() {
+    return /* @type {number} */ 42;
+}
+
+//// [jsdocCastCommentEmit.js]
+// allowJs: true
+// checkJs: true
+// outDir: out/
+// filename: input.js
+function f() {
+    return /* @type {number} */ 42;
+}
diff --git a/tests/baselines/reference/jsdocCastCommentEmit.symbols b/tests/baselines/reference/jsdocCastCommentEmit.symbols
@@ -0,0 +1,10 @@
+=== tests/cases/compiler/jsdocCastCommentEmit.ts ===
+// allowJs: true
+// checkJs: true
+// outDir: out/
+// filename: input.js
+function f() {
+>f : Symbol(f, Decl(jsdocCastCommentEmit.ts, 0, 0))
+
+    return /* @type {number} */ 42;
+}
diff --git a/tests/baselines/reference/jsdocCastCommentEmit.types b/tests/baselines/reference/jsdocCastCommentEmit.types
@@ -0,0 +1,11 @@
+=== tests/cases/compiler/jsdocCastCommentEmit.ts ===
+// allowJs: true
+// checkJs: true
+// outDir: out/
+// filename: input.js
+function f() {
+>f : () => number
+
+    return /* @type {number} */ 42;
+>42 : 42
+}
diff --git a/tests/cases/compiler/jsdocCastCommentEmit.ts b/tests/cases/compiler/jsdocCastCommentEmit.ts
@@ -0,0 +1,7 @@
+// allowJs: true
+// checkJs: true
+// outDir: out/
+// filename: input.js
+function f() {
+    return /* @type {number} */ 42;
+}

Original file line number	Diff line number	Diff line change
`@@ -8,7 +8,7 @@ namespace ts {`
`8`	`8`	`setWriter(writer: EmitTextWriter): void;`
`9`	`9`	`emitNodeWithComments(hint: EmitHint, node: Node, emitCallback: (hint: EmitHint, node: Node) => void): void;`
`10`	`10`	`emitBodyWithDetachedComments(node: Node, detachedRange: TextRange, emitCallback: (node: Node) => void): void;`
`11`		`- emitTrailingCommentsOfPosition(pos: number): void;`
	`11`	`+ emitTrailingCommentsOfPosition(pos: number, prefixSpace?: boolean): void;`
`12`	`12`	`emitLeadingCommentsOfPosition(pos: number): void;`
`13`	`13`	`}`
`14`	`14`
`@@ -306,7 +306,7 @@ namespace ts {`
`306`	`306`	`}`
`307`	`307`	`}`
`308`	`308`
`309`		`- function emitTrailingCommentsOfPosition(pos: number) {`
	`309`	`+ function emitTrailingCommentsOfPosition(pos: number, prefixSpace?: boolean) {`
`310`	`310`	`if (disabled) {`
`311`	`311`	`return;`
`312`	`312`	`}`
`@@ -315,7 +315,7 @@ namespace ts {`
`315`	`315`	`performance.mark("beforeEmitTrailingCommentsOfPosition");`
`316`	`316`	`}`
`317`	`317`
`318`		`- forEachTrailingCommentToEmit(pos, emitTrailingCommentOfPosition);`
	`318`	`+ forEachTrailingCommentToEmit(pos, prefixSpace ? emitTrailingComment : emitTrailingCommentOfPosition);`
`319`	`319`
`320`	`320`	`if (extendedDiagnostics) {`
`321`	`321`	`performance.measure("commentTime", "beforeEmitTrailingCommentsOfPosition");`