diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index 90738d828beb9..2f19c9b3d3206 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -1305,28 +1305,28 @@ namespace ts {
             writeToken(SyntaxKind.OpenParenToken, openParenPos, node);
             emitExpression(node.expression);
             writeToken(SyntaxKind.CloseParenToken, node.expression.end, node);
-            emitEmbeddedStatement(node.thenStatement);
+            emitEmbeddedStatement(node, node.thenStatement);
             if (node.elseStatement) {
-                writeLine();
+                writeLineOrSpace(node);
                 writeToken(SyntaxKind.ElseKeyword, node.thenStatement.end, node);
                 if (node.elseStatement.kind === SyntaxKind.IfStatement) {
                     write(" ");
                     emit(node.elseStatement);
                 }
                 else {
-                    emitEmbeddedStatement(node.elseStatement);
+                    emitEmbeddedStatement(node, node.elseStatement);
                 }
             }
         }
 
         function emitDoStatement(node: DoStatement) {
             write("do");
-            emitEmbeddedStatement(node.statement);
+            emitEmbeddedStatement(node, node.statement);
             if (isBlock(node.statement)) {
                 write(" ");
             }
             else {
-                writeLine();
+                writeLineOrSpace(node);
             }
 
             write("while (");
@@ -1338,7 +1338,7 @@ namespace ts {
             write("while (");
             emitExpression(node.expression);
             write(")");
-            emitEmbeddedStatement(node.statement);
+            emitEmbeddedStatement(node, node.statement);
         }
 
         function emitForStatement(node: ForStatement) {
@@ -1351,7 +1351,7 @@ namespace ts {
             write(";");
             emitExpressionWithPrefix(" ", node.incrementor);
             write(")");
-            emitEmbeddedStatement(node.statement);
+            emitEmbeddedStatement(node, node.statement);
         }
 
         function emitForInStatement(node: ForInStatement) {
@@ -1362,7 +1362,7 @@ namespace ts {
             write(" in ");
             emitExpression(node.expression);
             writeToken(SyntaxKind.CloseParenToken, node.expression.end);
-            emitEmbeddedStatement(node.statement);
+            emitEmbeddedStatement(node, node.statement);
         }
 
         function emitForOfStatement(node: ForOfStatement) {
@@ -1373,7 +1373,7 @@ namespace ts {
             write(" of ");
             emitExpression(node.expression);
             writeToken(SyntaxKind.CloseParenToken, node.expression.end);
-            emitEmbeddedStatement(node.statement);
+            emitEmbeddedStatement(node, node.statement);
         }
 
         function emitForBinding(node: VariableDeclarationList | Expression) {
@@ -1409,7 +1409,7 @@ namespace ts {
             write("with (");
             emitExpression(node.expression);
             write(")");
-            emitEmbeddedStatement(node.statement);
+            emitEmbeddedStatement(node, node.statement);
         }
 
         function emitSwitchStatement(node: SwitchStatement) {
@@ -1437,9 +1437,12 @@ namespace ts {
         function emitTryStatement(node: TryStatement) {
             write("try ");
             emit(node.tryBlock);
-            emit(node.catchClause);
+            if (node.catchClause) {
+                writeLineOrSpace(node);
+                emit(node.catchClause);
+            }
             if (node.finallyBlock) {
-                writeLine();
+                writeLineOrSpace(node);
                 write("finally ");
                 emit(node.finallyBlock);
             }
@@ -2125,8 +2128,8 @@ namespace ts {
             }
         }
 
-        function emitEmbeddedStatement(node: Statement) {
-            if (isBlock(node)) {
+        function emitEmbeddedStatement(parent: Node, node: Statement) {
+            if (isBlock(node) || getEmitFlags(parent) & EmitFlags.SingleLine) {
                 write(" ");
                 emit(node);
             }
@@ -2291,6 +2294,15 @@ namespace ts {
             }
         }
 
+        function writeLineOrSpace(node: Node) {
+            if (getEmitFlags(node) & EmitFlags.SingleLine) {
+                write(" ");
+            }
+            else {
+                writeLine();
+            }
+        }
+
         function writeIfAny(nodes: NodeArray<Node>, text: string) {
             if (nodes && nodes.length > 0) {
                 write(text);
diff --git a/src/compiler/transformers/generators.ts b/src/compiler/transformers/generators.ts
index c383902d4959e..1b909da4f6afa 100644
--- a/src/compiler/transformers/generators.ts
+++ b/src/compiler/transformers/generators.ts
@@ -938,7 +938,7 @@ namespace ts {
             }
 
             markLabel(resumeLabel);
-            return createGeneratorResume();
+            return createGeneratorResume(/*location*/ node);
         }
 
         /**
@@ -1234,7 +1234,9 @@ namespace ts {
 
         function transformAndEmitVariableDeclarationList(node: VariableDeclarationList): VariableDeclarationList {
             for (const variable of node.declarations) {
-                hoistVariableDeclaration(<Identifier>variable.name);
+                const name = getSynthesizedClone(<Identifier>variable.name);
+                setCommentRange(name, variable.name);
+                hoistVariableDeclaration(name);
             }
 
             const variables = getInitializedVariables(node);
@@ -1287,7 +1289,7 @@ namespace ts {
                 if (containsYield(node.thenStatement) || containsYield(node.elseStatement)) {
                     const endLabel = defineLabel();
                     const elseLabel = node.elseStatement ? defineLabel() : undefined;
-                    emitBreakWhenFalse(node.elseStatement ? elseLabel : endLabel, visitNode(node.expression, visitor, isExpression));
+                    emitBreakWhenFalse(node.elseStatement ? elseLabel : endLabel, visitNode(node.expression, visitor, isExpression), /*location*/ node.expression);
                     transformAndEmitEmbeddedStatement(node.thenStatement);
                     if (node.elseStatement) {
                         emitBreak(endLabel);
@@ -2965,12 +2967,15 @@ namespace ts {
             lastOperationWasAbrupt = true;
             lastOperationWasCompletion = true;
             writeStatement(
-                createReturn(
-                    createArrayLiteral(expression
-                        ? [createInstruction(Instruction.Return), expression]
-                        : [createInstruction(Instruction.Return)]
+                setEmitFlags(
+                    createReturn(
+                        createArrayLiteral(expression
+                            ? [createInstruction(Instruction.Return), expression]
+                            : [createInstruction(Instruction.Return)]
+                        ),
+                        operationLocation
                     ),
-                    operationLocation
+                    EmitFlags.NoTokenSourceMaps
                 )
             );
         }
@@ -2984,12 +2989,15 @@ namespace ts {
         function writeBreak(label: Label, operationLocation: TextRange): void {
             lastOperationWasAbrupt = true;
             writeStatement(
-                createReturn(
-                    createArrayLiteral([
-                        createInstruction(Instruction.Break),
-                        createLabel(label)
-                    ]),
-                    operationLocation
+                setEmitFlags(
+                    createReturn(
+                        createArrayLiteral([
+                            createInstruction(Instruction.Break),
+                            createLabel(label)
+                        ]),
+                        operationLocation
+                    ),
+                    EmitFlags.NoTokenSourceMaps
                 )
             );
         }
@@ -3003,15 +3011,21 @@ namespace ts {
          */
         function writeBreakWhenTrue(label: Label, condition: Expression, operationLocation: TextRange): void {
             writeStatement(
-                createIf(
-                    condition,
-                    createReturn(
-                        createArrayLiteral([
-                            createInstruction(Instruction.Break),
-                            createLabel(label)
-                        ]),
-                        operationLocation
-                    )
+                setEmitFlags(
+                    createIf(
+                        condition,
+                        setEmitFlags(
+                            createReturn(
+                                createArrayLiteral([
+                                    createInstruction(Instruction.Break),
+                                    createLabel(label)
+                                ]),
+                                operationLocation
+                            ),
+                            EmitFlags.NoTokenSourceMaps
+                        )
+                    ),
+                    EmitFlags.SingleLine
                 )
             );
         }
@@ -3025,15 +3039,21 @@ namespace ts {
          */
         function writeBreakWhenFalse(label: Label, condition: Expression, operationLocation: TextRange): void {
             writeStatement(
-                createIf(
-                    createLogicalNot(condition),
-                    createReturn(
-                        createArrayLiteral([
-                            createInstruction(Instruction.Break),
-                            createLabel(label)
-                        ]),
-                        operationLocation
-                    )
+                setEmitFlags(
+                    createIf(
+                        createLogicalNot(condition),
+                        setEmitFlags(
+                            createReturn(
+                                createArrayLiteral([
+                                    createInstruction(Instruction.Break),
+                                    createLabel(label)
+                                ]),
+                                operationLocation
+                            ),
+                            EmitFlags.NoTokenSourceMaps
+                        )
+                    ),
+                    EmitFlags.SingleLine
                 )
             );
         }
@@ -3047,13 +3067,16 @@ namespace ts {
         function writeYield(expression: Expression, operationLocation: TextRange): void {
             lastOperationWasAbrupt = true;
             writeStatement(
-                createReturn(
-                    createArrayLiteral(
-                        expression
-                            ? [createInstruction(Instruction.Yield), expression]
-                            : [createInstruction(Instruction.Yield)]
+                setEmitFlags(
+                    createReturn(
+                        createArrayLiteral(
+                            expression
+                                ? [createInstruction(Instruction.Yield), expression]
+                                : [createInstruction(Instruction.Yield)]
+                        ),
+                        operationLocation
                     ),
-                    operationLocation
+                    EmitFlags.NoTokenSourceMaps
                 )
             );
         }
@@ -3067,12 +3090,15 @@ namespace ts {
         function writeYieldStar(expression: Expression, operationLocation: TextRange): void {
             lastOperationWasAbrupt = true;
             writeStatement(
-                createReturn(
-                    createArrayLiteral([
-                        createInstruction(Instruction.YieldStar),
-                        expression
-                    ]),
-                    operationLocation
+                setEmitFlags(
+                    createReturn(
+                        createArrayLiteral([
+                            createInstruction(Instruction.YieldStar),
+                            expression
+                        ]),
+                        operationLocation
+                    ),
+                    EmitFlags.NoTokenSourceMaps
                 )
             );
         }