Fix for dropped/extra comments

src/compiler/emitter.ts

@@ -2845,6 +2845,26 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
                 }
             }
 
+            function emitEmptyBlockComments(node: Node) {
+                // special handling for empty blocks
+                let pos = node.pos;
+
+                // skipping leading comments
+                const comments = getLeadingCommentRanges(currentText, node.pos);
+
+                if (comments) {
+                    const lastComment = lastOrUndefined(comments);
+                    if (lastComment) {
+                        pos = lastComment.end;
+                    }
+                }
+
+                pos = currentText.indexOf("{", pos) + 1;
+                // emitting all comments after '{'
+                emitTrailingCommentsOfPosition(pos);
+                emitLeadingCommentsOfPosition(pos);
+            }
+
             function emitBlock(node: Block) {
                 if (isSingleLineEmptyBlock(node)) {
                     emitToken(SyntaxKind.OpenBraceToken, node.pos);
@@ -2855,6 +2875,15 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
 
                 emitToken(SyntaxKind.OpenBraceToken, node.pos);
                 increaseIndent();
+
+                if (!!node.statements.length) {
+                    const firstStatementNode = node.statements[0];
+                    emitTrailingCommentsOfPosition(firstStatementNode.pos);
+                }
+                else {
+                    emitEmptyBlockComments(node);
+                }
+
                 if (node.kind === SyntaxKind.ModuleBlock) {
                     Debug.assert(node.parent.kind === SyntaxKind.ModuleDeclaration);
                     emitCaptureThisForNodeIfNecessary(node.parent);
@@ -2863,6 +2892,12 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
                 if (node.kind === SyntaxKind.ModuleBlock) {
                     emitTempDeclarations(/*newLine*/ true);
                 }
+
+                if (!!node.statements.length) {
+                    const lastStatementNode = lastOrUndefined(node.statements);
+                    emitLeadingCommentsOfPosition(lastStatementNode.end);
+                }
+
                 decreaseIndent();
                 writeLine();
                 emitToken(SyntaxKind.CloseBraceToken, node.statements.end);
@@ -2894,6 +2929,7 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
                 emitToken(SyntaxKind.CloseParenToken, node.expression.end);
                 emitEmbeddedStatement(node.thenStatement);
                 if (node.elseStatement) {
+                    emitLeadingCommentsOfPosition(node.thenStatement.end);
                     writeLine();
                     emitToken(SyntaxKind.ElseKeyword, node.thenStatement.end);
                     if (node.elseStatement.kind === SyntaxKind.IfStatement) {
@@ -4558,6 +4594,7 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
                 const { kind, parent } = node;
                 if (kind !== SyntaxKind.MethodDeclaration &&
                     kind !== SyntaxKind.MethodSignature &&
+                    kind !== SyntaxKind.ArrowFunction &&
                     parent &&
                     parent.kind !== SyntaxKind.PropertyAssignment &&
                     parent.kind !== SyntaxKind.CallExpression &&

tests/baselines/reference/amdImportAsPrimaryExpression.js

@@ -26,5 +26,6 @@ define(["require", "exports"], function (require, exports) {
 define(["require", "exports", "./foo_0"], function (require, exports, foo) {
     "use strict";
     if (foo.E1.A === 0) {
+        // Should cause runtime import - interesting optimization possibility, as gets inlined to 0.
     }
 });

tests/baselines/reference/argsInScope.js

@@ -17,6 +17,7 @@ var C = (function () {
     }
     C.prototype.P = function (ii, j, k) {
         for (var i = 0; i < arguments.length; i++) {
+            // WScript.Echo("param: " + arguments[i]);
         }
     };
     return C;

tests/baselines/reference/augmentedTypesModules.js

@@ -111,7 +111,7 @@ var m1b;
 var m1b = 1; // error
 var m1c = 1; // Should be allowed
 var m1d;
-(function (m1d) {
+(function (m1d) {// error
     var I = (function () {
         function I() {
         }

tests/baselines/reference/collisionCodeGenModuleWithAccessorChildren.js

@@ -79,7 +79,7 @@ var M;
     }());
 })(M || (M = {}));
 var M;
-(function (M) {
+(function (M) {// Shouldnt be _M
     var e = (function () {
         function e() {
         }
@@ -110,7 +110,7 @@ var M;
     }());
 })(M || (M = {}));
 var M;
-(function (M) {
+(function (M) {// Shouldnt be _M
     var e = (function () {
         function e() {
         }

tests/baselines/reference/collisionCodeGenModuleWithMethodChildren.js

@@ -71,7 +71,7 @@ var M;
     }());
 })(M || (M = {}));
 var M;
-(function (M) {
+(function (M) {// Shouldnt bn _M
     var f = (function () {
         function f() {
         }

tests/baselines/reference/collisionCodeGenModuleWithModuleChildren.js

@@ -76,7 +76,7 @@ var M;
     })(m3 || (m3 = {}));
 })(M || (M = {}));
 var M;
-(function (M) {
+(function (M) {// shouldnt be _M
     var m3;
     (function (m3) {
         var p = M.x;

tests/baselines/reference/collisionThisExpressionAndModuleInGlobal.js

@@ -8,7 +8,7 @@ var f = () => this;
 //// [collisionThisExpressionAndModuleInGlobal.js]
 var _this = this;
 var _this;
-(function (_this) {
+(function (_this) {//Error
     var c = (function () {
         function c() {
         }

tests/baselines/reference/commentOnIfElseStatement1.js

@@ -0,0 +1,24 @@
+//// [commentOnIfElseStatement1.ts]
+
+// 1
+if (false) {
+}
+// 2
+else if (!true) {
+
+}
+// 3
+else {
+
+}
+
+//// [commentOnIfElseStatement1.js]
+// 1
+if (false) {
+}
+// 2
+else if (!true) {
+}
+// 3
+else {
+}

tests/baselines/reference/commentOnIfElseStatement1.symbols

@@ -0,0 +1,14 @@
+=== tests/cases/compiler/commentOnIfElseStatement1.ts ===
+
+No type information for this code.// 1
+No type information for this code.if (false) {
+No type information for this code.}
+No type information for this code.// 2
+No type information for this code.else if (!true) {
+No type information for this code.
+No type information for this code.}
+No type information for this code.// 3
+No type information for this code.else {
+No type information for this code.	
+No type information for this code.}
+No type information for this code.

tests/baselines/reference/commentOnIfElseStatement1.types

@@ -0,0 +1,16 @@
+=== tests/cases/compiler/commentOnIfElseStatement1.ts ===
+
+// 1
+if (false) {
+>false : boolean
+}
+// 2
+else if (!true) {
+>!true : boolean
+>true : boolean
+
+}
+// 3
+else {
+
+}

tests/baselines/reference/commentsBeforeFunctionExpression1.js

@@ -2,9 +2,13 @@
 var v = {
     f: /**own f*/ (a) => 0
 }
+var w = 
+/* 1 */ (a) => 0;
 
 
 //// [commentsBeforeFunctionExpression1.js]
 var v = {
     f: /**own f*/ function (a) { return 0; }
 };
+var w = 
+/* 1 */ function (a) { return 0; };

tests/baselines/reference/commentsBeforeFunctionExpression1.symbols

@@ -6,4 +6,9 @@ var v = {
 >f : Symbol(f, Decl(commentsBeforeFunctionExpression1.ts, 0, 9))
 >a : Symbol(a, Decl(commentsBeforeFunctionExpression1.ts, 1, 19))
 }
+var w = 
+>w : Symbol(w, Decl(commentsBeforeFunctionExpression1.ts, 3, 3))
+
+/* 1 */ (a) => 0;
+>a : Symbol(a, Decl(commentsBeforeFunctionExpression1.ts, 4, 9))
 

tests/baselines/reference/commentsBeforeFunctionExpression1.types

@@ -9,4 +9,11 @@ var v = {
 >a : any
 >0 : number
 }
+var w = 
+>w : (a: any) => number
+
+/* 1 */ (a) => 0;
+>(a) => 0 : (a: any) => number
+>a : any
+>0 : number
 

tests/baselines/reference/commonJSImportAsPrimaryExpression.js

@@ -27,4 +27,5 @@ exports.C1 = C1;
 "use strict";
 var foo = require("./foo_0");
 if (foo.C1.s1) {
+    // Should cause runtime import
 }

tests/baselines/reference/duplicateAnonymousInners1.js

@@ -49,4 +49,6 @@ var Foo;
         }
         return Helper;
     }());
+    // Inner should not show up in intellisense
+    // Outer should show up in intellisense
 })(Foo || (Foo = {}));

tests/baselines/reference/duplicateLocalVariable1.js

@@ -382,7 +382,7 @@ var TestRunner = (function () {
                 exception = true;
                 testResult = false;
                 if (typeof testcase.errorMessageRegEx === "string") {
-                    if (testcase.errorMessageRegEx === "") {
+                    if (testcase.errorMessageRegEx === "") {// Any error is fine
                         testResult = true;
                     }
                     else if (e.message) {
@@ -391,6 +391,7 @@ var TestRunner = (function () {
                     }
                 }
                 if (testResult === false) {
+                    //console.log(e.message);
                 }
             }
             if ((testcase.errorMessageRegEx !== undefined) && !exception) {

tests/baselines/reference/duplicateSymbolsExportMatching.js

@@ -76,7 +76,7 @@ define(["require", "exports"], function (require, exports) {
             var t;
         })(inst || (inst = {}));
         var inst;
-        (function (inst) {
+        (function (inst) {// one error
             var t;
         })(inst = M.inst || (M.inst = {}));
     })(M || (M = {}));
@@ -103,7 +103,7 @@ define(["require", "exports"], function (require, exports) {
             return C;
         }());
         var C;
-        (function (C) {
+        (function (C) {// Two visibility errors (one for the clodule symbol, and one for the merged container symbol)
             var t;
         })(C = M.C || (M.C = {}));
     })(M || (M = {}));

tests/baselines/reference/for.js

@@ -32,26 +32,26 @@ for () { // error
 }
 
 //// [for.js]
-for (var i = 0; i < 10; i++) {
+for (var i = 0; i < 10; i++) {// ok
     var x1 = i;
 }
-for (var j = 0; j < 10; j++) {
+for (var j = 0; j < 10; j++) {// ok
     var x2 = j;
 }
-for (var k = 0; k < 10;) {
+for (var k = 0; k < 10;) {// ok
     k++;
 }
-for (; i < 10;) {
+for (; i < 10;) {// ok
     i++;
 }
-for (; i > 1; i--) {
+for (; i > 1; i--) {// ok
 }
-for (var l = 0;; l++) {
+for (var l = 0;; l++) {// ok
     if (l > 10) {
         break;
     }
 }
-for (;;) {
+for (;;) {// ok
 }
-for (;;) {
+for (;;) {// error
 }

tests/baselines/reference/forIn.js

@@ -23,16 +23,16 @@ for (var l in arr) {
 
 //// [forIn.js]
 var arr = null;
-for (var i in arr) {
+for (var i in arr) {// error
     var x1 = arr[i];
     var y1 = arr[i];
 }
-for (var j in arr) {
+for (var j in arr) {// ok
     var x2 = arr[j];
     var y2 = arr[j];
 }
 var arr2 = [];
-for (j in arr2) {
+for (j in arr2) {// ok
     var x3 = arr2[j];
     var y3 = arr2[j];
 }

tests/baselines/reference/invalidTryStatements2.js

@@ -32,7 +32,7 @@ function fn2() {
 function fn() {
     try {
     }
-    catch () {
+    catch () {// syntax error, missing '(x)'
     }
     try {
     }

tests/baselines/reference/jsFileCompilationLetBeingRenamed.js

@@ -9,5 +9,6 @@ function foo(a) {
 //// [out.js]
 function foo(a) {
     for (var a_1 = 0; a_1 < 10; a_1++) {
+        // do something
     }
 }

tests/baselines/reference/moduleDuplicateIdentifiers.js

@@ -49,7 +49,7 @@ var FooBar;
     FooBar.member1 = 2;
 })(FooBar = exports.FooBar || (exports.FooBar = {}));
 var FooBar;
-(function (FooBar) {
+(function (FooBar) {// Shouldn't error
     FooBar.member2 = 42;
 })(FooBar = exports.FooBar || (exports.FooBar = {}));
 var Kettle = (function () {

tests/baselines/reference/nameCollisions.js

@@ -52,7 +52,7 @@ var T;
 (function (T) {
     var x = 2;
     var x;
-    (function (x) {
+    (function (x) {// error
         var Bar = (function () {
             function Bar() {
             }