diff --git a/lib/tsc.js b/lib/tsc.js
index 33eeb6de3af..d0fb24e1321 100644
--- a/lib/tsc.js
+++ b/lib/tsc.js
@@ -11088,7 +11088,8 @@ var ts;
             return token() === 24 ||
                 isIdentifierOrPattern() ||
                 ts.isModifierKind(token()) ||
-                token() === 57 || isStartOfType();
+                token() === 57 ||
+                isStartOfType(true);
         }
         function parseParameter() {
             var node = createNode(146);
@@ -11427,7 +11428,7 @@ var ts;
                     return parseTypeReference();
             }
         }
-        function isStartOfType() {
+        function isStartOfType(inStartOfParameter) {
             switch (token()) {
                 case 119:
                 case 136:
@@ -11454,9 +11455,9 @@ var ts;
                 case 39:
                     return true;
                 case 38:
-                    return lookAhead(nextTokenIsNumericLiteral);
+                    return !inStartOfParameter && lookAhead(nextTokenIsNumericLiteral);
                 case 19:
-                    return lookAhead(isStartOfParenthesizedOrFunctionType);
+                    return !inStartOfParameter && lookAhead(isStartOfParenthesizedOrFunctionType);
                 default:
                     return isIdentifier();
             }
diff --git a/lib/tsserver.js b/lib/tsserver.js
index 21b0b83c062..c1075eb4971 100644
--- a/lib/tsserver.js
+++ b/lib/tsserver.js
@@ -12958,7 +12958,8 @@ var ts;
             return token() === 24 ||
                 isIdentifierOrPattern() ||
                 ts.isModifierKind(token()) ||
-                token() === 57 || isStartOfType();
+                token() === 57 ||
+                isStartOfType(true);
         }
         function parseParameter() {
             var node = createNode(146);
@@ -13297,7 +13298,7 @@ var ts;
                     return parseTypeReference();
             }
         }
-        function isStartOfType() {
+        function isStartOfType(inStartOfParameter) {
             switch (token()) {
                 case 119:
                 case 136:
@@ -13324,9 +13325,9 @@ var ts;
                 case 39:
                     return true;
                 case 38:
-                    return lookAhead(nextTokenIsNumericLiteral);
+                    return !inStartOfParameter && lookAhead(nextTokenIsNumericLiteral);
                 case 19:
-                    return lookAhead(isStartOfParenthesizedOrFunctionType);
+                    return !inStartOfParameter && lookAhead(isStartOfParenthesizedOrFunctionType);
                 default:
                     return isIdentifier();
             }
@@ -74425,7 +74426,9 @@ var ts;
                     deleteCallback();
                 }
                 return {
-                    edits: changeTracker.getChanges()
+                    edits: changeTracker.getChanges(),
+                    renameFilename: undefined,
+                    renameLocation: undefined,
                 };
                 function deleteNode(node, inList) {
                     if (inList === void 0) { inList = false; }
@@ -74576,11 +74579,11 @@ var ts;
                 var usedNames = ts.createMap();
                 var i = 0;
                 for (var _i = 0, extractions_1 = extractions; _i < extractions_1.length; _i++) {
-                    var extr = extractions_1[_i];
-                    if (extr.errors && extr.errors.length) {
+                    var _a = extractions_1[_i], scopeDescription = _a.scopeDescription, errors = _a.errors;
+                    if (errors.length) {
                         continue;
                     }
-                    var description = ts.formatStringFromArgs(ts.Diagnostics.Extract_function_into_0.message, [extr.scopeDescription]);
+                    var description = ts.formatStringFromArgs(ts.Diagnostics.Extract_function_into_0.message, [scopeDescription]);
                     if (!usedNames.has(description)) {
                         usedNames.set(description, true);
                         actions.push({
@@ -74608,9 +74611,7 @@ var ts;
                 ts.Debug.assert(!!parsedIndexMatch, "Scope name should have matched the regexp");
                 var index = +parsedIndexMatch[1];
                 ts.Debug.assert(isFinite(index), "Expected to parse a finite number from the scope index");
-                var extractions = getPossibleExtractions(targetRange, context, index);
-                ts.Debug.assert(extractions !== undefined, "The extraction went missing? How?");
-                return ({ edits: extractions[0].changes });
+                return getExtractionAtIndex(targetRange, context, index);
             }
             var Messages;
             (function (Messages) {
@@ -74639,7 +74640,7 @@ var ts;
                 RangeFacts[RangeFacts["IsAsyncFunction"] = 4] = "IsAsyncFunction";
                 RangeFacts[RangeFacts["UsesThis"] = 8] = "UsesThis";
                 RangeFacts[RangeFacts["InStaticRegion"] = 16] = "InStaticRegion";
-            })(RangeFacts = extractMethod_1.RangeFacts || (extractMethod_1.RangeFacts = {}));
+            })(RangeFacts || (RangeFacts = {}));
             function getRangeToExtract(sourceFile, span) {
                 var length = span.length || 0;
                 var start = getParentNodeInSpan(ts.getTokenAtPosition(sourceFile, span.start, false), sourceFile, span);
@@ -74879,7 +74880,7 @@ var ts;
                 return undefined;
             }
             function isValidExtractionTarget(node) {
-                return (node.kind === 228) || ts.isSourceFile(node) || isModuleBlock(node) || ts.isClassLike(node);
+                return (node.kind === 228) || ts.isSourceFile(node) || ts.isModuleBlock(node) || ts.isClassLike(node);
             }
             function collectEnclosingScopes(range) {
                 var current = isReadonlyArray(range.range) ? ts.firstOrUndefined(range.range) : range.range;
@@ -74904,9 +74905,21 @@ var ts;
                 }
                 return scopes;
             }
-            extractMethod_1.collectEnclosingScopes = collectEnclosingScopes;
-            function getPossibleExtractions(targetRange, context, requestedChangesIndex) {
-                if (requestedChangesIndex === void 0) { requestedChangesIndex = undefined; }
+            function getExtractionAtIndex(targetRange, context, requestedChangesIndex) {
+                var _a = getPossibleExtractionsWorker(targetRange, context), scopes = _a.scopes, _b = _a.readsAndWrites, target = _b.target, usagesPerScope = _b.usagesPerScope, errorsPerScope = _b.errorsPerScope;
+                ts.Debug.assert(!errorsPerScope[requestedChangesIndex].length, "The extraction went missing? How?");
+                context.cancellationToken.throwIfCancellationRequested();
+                return extractFunctionInScope(target, scopes[requestedChangesIndex], usagesPerScope[requestedChangesIndex], targetRange, context);
+            }
+            extractMethod_1.getExtractionAtIndex = getExtractionAtIndex;
+            function getPossibleExtractions(targetRange, context) {
+                var extractions = getPossibleExtractionsWorker(targetRange, context);
+                return extractions && extractions.scopes.map(function (scope, i) {
+                    return ({ scopeDescription: getDescriptionForScope(scope), errors: extractions.readsAndWrites.errorsPerScope[i] });
+                });
+            }
+            extractMethod_1.getPossibleExtractions = getPossibleExtractions;
+            function getPossibleExtractionsWorker(targetRange, context) {
                 var sourceFile = context.file;
                 if (targetRange === undefined) {
                     return undefined;
@@ -74916,29 +74929,9 @@ var ts;
                     return undefined;
                 }
                 var enclosingTextRange = getEnclosingTextRange(targetRange, sourceFile);
-                var _a = collectReadsAndWrites(targetRange, scopes, enclosingTextRange, sourceFile, context.program.getTypeChecker()), target = _a.target, usagesPerScope = _a.usagesPerScope, errorsPerScope = _a.errorsPerScope;
-                context.cancellationToken.throwIfCancellationRequested();
-                if (requestedChangesIndex !== undefined) {
-                    if (errorsPerScope[requestedChangesIndex].length) {
-                        return undefined;
-                    }
-                    return [extractFunctionInScope(target, scopes[requestedChangesIndex], usagesPerScope[requestedChangesIndex], targetRange, context)];
-                }
-                else {
-                    return scopes.map(function (scope, i) {
-                        var errors = errorsPerScope[i];
-                        if (errors.length) {
-                            return {
-                                scope: scope,
-                                scopeDescription: getDescriptionForScope(scope),
-                                errors: errors
-                            };
-                        }
-                        return { scope: scope, scopeDescription: getDescriptionForScope(scope) };
-                    });
-                }
+                var readsAndWrites = collectReadsAndWrites(targetRange, scopes, enclosingTextRange, sourceFile, context.program.getTypeChecker());
+                return { scopes: scopes, readsAndWrites: readsAndWrites };
             }
-            extractMethod_1.getPossibleExtractions = getPossibleExtractions;
             function getDescriptionForScope(scope) {
                 if (ts.isFunctionLike(scope)) {
                     switch (scope.kind) {
@@ -74960,7 +74953,7 @@ var ts;
                             return "'set " + scope.name.getText() + "'";
                     }
                 }
-                else if (isModuleBlock(scope)) {
+                else if (ts.isModuleBlock(scope)) {
                     return "namespace '" + scope.parent.name.getText() + "'";
                 }
                 else if (ts.isClassLike(scope)) {
@@ -74977,14 +74970,10 @@ var ts;
                     return "unknown";
                 }
             }
-            function getUniqueName(isNameOkay) {
+            function getUniqueName(fileText) {
                 var functionNameText = "newFunction";
-                if (isNameOkay(functionNameText)) {
-                    return functionNameText;
-                }
-                var i = 1;
-                while (!isNameOkay(functionNameText = "newFunction_" + i)) {
-                    i++;
+                for (var i = 1; fileText.indexOf(functionNameText) !== -1; i++) {
+                    functionNameText = "newFunction_" + i;
                 }
                 return functionNameText;
             }
@@ -74992,10 +74981,9 @@ var ts;
                 var usagesInScope = _a.usages, substitutions = _a.substitutions;
                 var checker = context.program.getTypeChecker();
                 var file = scope.getSourceFile();
-                var functionNameText = getUniqueName(function (n) { return !file.identifiers.has(n); });
+                var functionNameText = getUniqueName(file.text);
                 var isJS = ts.isInJavaScriptFile(scope);
                 var functionName = ts.createIdentifier(functionNameText);
-                var functionReference = ts.createIdentifier(functionNameText);
                 var returnType = undefined;
                 var parameters = [];
                 var callArguments = [];
@@ -75018,7 +75006,7 @@ var ts;
                     var contextualType = checker.getContextualType(node);
                     returnType = checker.typeToTypeNode(contextualType);
                 }
-                var _b = transformFunctionBody(node), body = _b.body, returnValueProperty = _b.returnValueProperty;
+                var _b = transformFunctionBody(node, writes, substitutions, !!(range.facts & RangeFacts.HasReturn)), body = _b.body, returnValueProperty = _b.returnValueProperty;
                 var newFunction;
                 if (ts.isClassLike(scope)) {
                     var modifiers = isJS ? [] : [ts.createToken(112)];
@@ -75036,7 +75024,8 @@ var ts;
                 var changeTracker = ts.textChanges.ChangeTracker.fromCodeFixContext(context);
                 changeTracker.insertNodeBefore(context.file, scope.getLastToken(), newFunction, { prefix: context.newLineCharacter, suffix: context.newLineCharacter });
                 var newNodes = [];
-                var call = ts.createCall(ts.isClassLike(scope) ? ts.createPropertyAccess(range.facts & RangeFacts.InStaticRegion ? ts.createIdentifier(scope.name.getText()) : ts.createThis(), functionReference) : functionReference, undefined, callArguments);
+                var called = getCalledExpression(scope, range, functionNameText);
+                var call = ts.createCall(called, undefined, callArguments);
                 if (range.facts & RangeFacts.IsGenerator) {
                     call = ts.createYield(ts.createToken(39), call);
                 }
@@ -75086,65 +75075,85 @@ var ts;
                 else {
                     changeTracker.replaceNodeWithNodes(context.file, range.range, newNodes, { nodeSeparator: context.newLineCharacter });
                 }
-                return {
-                    scope: scope,
-                    scopeDescription: getDescriptionForScope(scope),
-                    changes: changeTracker.getChanges()
-                };
-                function getPropertyAssignmentsForWrites(writes) {
-                    return writes.map(function (w) { return ts.createShorthandPropertyAssignment(w.symbol.name); });
-                }
-                function generateReturnValueProperty() {
-                    return "__return";
-                }
-                function transformFunctionBody(body) {
-                    if (ts.isBlock(body) && !writes && substitutions.size === 0) {
-                        return { body: ts.createBlock(body.statements, true), returnValueProperty: undefined };
-                    }
-                    var returnValueProperty;
-                    var statements = ts.createNodeArray(ts.isBlock(body) ? body.statements.slice(0) : [ts.isStatement(body) ? body : ts.createReturn(body)]);
-                    if (writes || substitutions.size) {
-                        var rewrittenStatements = ts.visitNodes(statements, visitor).slice();
-                        if (writes && !(range.facts & RangeFacts.HasReturn) && ts.isStatement(body)) {
-                            var assignments = getPropertyAssignmentsForWrites(writes);
-                            if (assignments.length === 1) {
-                                rewrittenStatements.push(ts.createReturn(assignments[0].name));
-                            }
-                            else {
-                                rewrittenStatements.push(ts.createReturn(ts.createObjectLiteral(assignments)));
-                            }
+                var edits = changeTracker.getChanges();
+                var renameRange = isReadonlyArray(range.range) ? range.range[0] : range.range;
+                var renameFilename = renameRange.getSourceFile().fileName;
+                var renameLocation = getRenameLocation(edits, renameFilename, functionNameText);
+                return { renameFilename: renameFilename, renameLocation: renameLocation, edits: edits };
+            }
+            function getRenameLocation(edits, renameFilename, functionNameText) {
+                var delta = 0;
+                for (var _i = 0, edits_1 = edits; _i < edits_1.length; _i++) {
+                    var _a = edits_1[_i], fileName = _a.fileName, textChanges_1 = _a.textChanges;
+                    ts.Debug.assert(fileName === renameFilename);
+                    for (var _b = 0, textChanges_2 = textChanges_1; _b < textChanges_2.length; _b++) {
+                        var change = textChanges_2[_b];
+                        var span_17 = change.span, newText = change.newText;
+                        var index = newText.indexOf(functionNameText);
+                        if (index !== -1) {
+                            return span_17.start + delta + index;
                         }
-                        return { body: ts.createBlock(rewrittenStatements, true), returnValueProperty: returnValueProperty };
+                        delta += newText.length - span_17.length;
                     }
-                    else {
-                        return { body: ts.createBlock(statements, true), returnValueProperty: undefined };
-                    }
-                    function visitor(node) {
-                        if (node.kind === 219 && writes) {
-                            var assignments = getPropertyAssignmentsForWrites(writes);
-                            if (node.expression) {
-                                if (!returnValueProperty) {
-                                    returnValueProperty = generateReturnValueProperty();
-                                }
-                                assignments.unshift(ts.createPropertyAssignment(returnValueProperty, ts.visitNode(node.expression, visitor)));
-                            }
-                            if (assignments.length === 1) {
-                                return ts.createReturn(assignments[0].name);
-                            }
-                            else {
-                                return ts.createReturn(ts.createObjectLiteral(assignments));
-                            }
+                }
+                throw new Error();
+            }
+            function getCalledExpression(scope, range, functionNameText) {
+                var functionReference = ts.createIdentifier(functionNameText);
+                if (ts.isClassLike(scope)) {
+                    var lhs = range.facts & RangeFacts.InStaticRegion ? ts.createIdentifier(scope.name.text) : ts.createThis();
+                    return ts.createPropertyAccess(lhs, functionReference);
+                }
+                else {
+                    return functionReference;
+                }
+            }
+            function transformFunctionBody(body, writes, substitutions, hasReturn) {
+                if (ts.isBlock(body) && !writes && substitutions.size === 0) {
+                    return { body: ts.createBlock(body.statements, true), returnValueProperty: undefined };
+                }
+                var returnValueProperty;
+                var statements = ts.createNodeArray(ts.isBlock(body) ? body.statements.slice(0) : [ts.isStatement(body) ? body : ts.createReturn(body)]);
+                if (writes || substitutions.size) {
+                    var rewrittenStatements = ts.visitNodes(statements, visitor).slice();
+                    if (writes && !hasReturn && ts.isStatement(body)) {
+                        var assignments = getPropertyAssignmentsForWrites(writes);
+                        if (assignments.length === 1) {
+                            rewrittenStatements.push(ts.createReturn(assignments[0].name));
                         }
                         else {
-                            var substitution = substitutions.get(ts.getNodeId(node).toString());
-                            return substitution || ts.visitEachChild(node, visitor, ts.nullTransformationContext);
+                            rewrittenStatements.push(ts.createReturn(ts.createObjectLiteral(assignments)));
                         }
                     }
+                    return { body: ts.createBlock(rewrittenStatements, true), returnValueProperty: returnValueProperty };
+                }
+                else {
+                    return { body: ts.createBlock(statements, true), returnValueProperty: undefined };
+                }
+                function visitor(node) {
+                    if (node.kind === 219 && writes) {
+                        var assignments = getPropertyAssignmentsForWrites(writes);
+                        if (node.expression) {
+                            if (!returnValueProperty) {
+                                returnValueProperty = "__return";
+                            }
+                            assignments.unshift(ts.createPropertyAssignment(returnValueProperty, ts.visitNode(node.expression, visitor)));
+                        }
+                        if (assignments.length === 1) {
+                            return ts.createReturn(assignments[0].name);
+                        }
+                        else {
+                            return ts.createReturn(ts.createObjectLiteral(assignments));
+                        }
+                    }
+                    else {
+                        var substitution = substitutions.get(ts.getNodeId(node).toString());
+                        return substitution || ts.visitEachChild(node, visitor, ts.nullTransformationContext);
+                    }
                 }
             }
-            extractMethod_1.extractFunctionInScope = extractFunctionInScope;
-            function isModuleBlock(n) {
-                return n.kind === 234;
+            function getPropertyAssignmentsForWrites(writes) {
+                return writes.map(function (w) { return ts.createShorthandPropertyAssignment(w.symbol.name); });
             }
             function isReadonlyArray(v) {
                 return ts.isArray(v);
@@ -81209,8 +81218,8 @@ var ts;
                 { start: start, end: end, text: text, code: code, category: category, source: source };
         }
         function allEditsBeforePos(edits, pos) {
-            for (var _i = 0, edits_1 = edits; _i < edits_1.length; _i++) {
-                var edit = edits_1[_i];
+            for (var _i = 0, edits_2 = edits; _i < edits_2.length; _i++) {
+                var edit = edits_2[_i];
                 if (ts.textSpanEnd(edit.span) >= pos) {
                     return false;
                 }
@@ -82372,12 +82381,12 @@ var ts;
                     return undefined;
                 }
                 if (simplifiedResult) {
-                    var span_17 = helpItems.applicableSpan;
+                    var span_18 = helpItems.applicableSpan;
                     return {
                         items: helpItems.items,
                         applicableSpan: {
-                            start: scriptInfo.positionToLineOffset(span_17.start),
-                            end: scriptInfo.positionToLineOffset(span_17.start + span_17.length)
+                            start: scriptInfo.positionToLineOffset(span_18.start),
+                            end: scriptInfo.positionToLineOffset(span_18.start + span_18.length)
                         },
                         selectedItemIndex: helpItems.selectedItemIndex,
                         argumentIndex: helpItems.argumentIndex,
diff --git a/lib/tsserverlibrary.d.ts b/lib/tsserverlibrary.d.ts
index 45701530600..4779895cbab 100644
--- a/lib/tsserverlibrary.d.ts
+++ b/lib/tsserverlibrary.d.ts
@@ -3283,8 +3283,8 @@ declare namespace ts {
     };
     type RefactorEditInfo = {
         edits: FileTextChanges[];
-        renameFilename?: string;
-        renameLocation?: number;
+        renameFilename: string | undefined;
+        renameLocation: number | undefined;
     };
     interface TextInsertion {
         newText: string;
diff --git a/lib/tsserverlibrary.js b/lib/tsserverlibrary.js
index bd74f810fb5..93916b40bff 100644
--- a/lib/tsserverlibrary.js
+++ b/lib/tsserverlibrary.js
@@ -12155,7 +12155,8 @@ var ts;
             return token() === 24 ||
                 isIdentifierOrPattern() ||
                 ts.isModifierKind(token()) ||
-                token() === 57 || isStartOfType();
+                token() === 57 ||
+                isStartOfType(true);
         }
         function parseParameter() {
             var node = createNode(146);
@@ -12494,7 +12495,7 @@ var ts;
                     return parseTypeReference();
             }
         }
-        function isStartOfType() {
+        function isStartOfType(inStartOfParameter) {
             switch (token()) {
                 case 119:
                 case 136:
@@ -12521,9 +12522,9 @@ var ts;
                 case 39:
                     return true;
                 case 38:
-                    return lookAhead(nextTokenIsNumericLiteral);
+                    return !inStartOfParameter && lookAhead(nextTokenIsNumericLiteral);
                 case 19:
-                    return lookAhead(isStartOfParenthesizedOrFunctionType);
+                    return !inStartOfParameter && lookAhead(isStartOfParenthesizedOrFunctionType);
                 default:
                     return isIdentifier();
             }
@@ -74425,7 +74426,9 @@ var ts;
                     deleteCallback();
                 }
                 return {
-                    edits: changeTracker.getChanges()
+                    edits: changeTracker.getChanges(),
+                    renameFilename: undefined,
+                    renameLocation: undefined,
                 };
                 function deleteNode(node, inList) {
                     if (inList === void 0) { inList = false; }
@@ -74576,11 +74579,11 @@ var ts;
                 var usedNames = ts.createMap();
                 var i = 0;
                 for (var _i = 0, extractions_1 = extractions; _i < extractions_1.length; _i++) {
-                    var extr = extractions_1[_i];
-                    if (extr.errors && extr.errors.length) {
+                    var _a = extractions_1[_i], scopeDescription = _a.scopeDescription, errors = _a.errors;
+                    if (errors.length) {
                         continue;
                     }
-                    var description = ts.formatStringFromArgs(ts.Diagnostics.Extract_function_into_0.message, [extr.scopeDescription]);
+                    var description = ts.formatStringFromArgs(ts.Diagnostics.Extract_function_into_0.message, [scopeDescription]);
                     if (!usedNames.has(description)) {
                         usedNames.set(description, true);
                         actions.push({
@@ -74608,9 +74611,7 @@ var ts;
                 ts.Debug.assert(!!parsedIndexMatch, "Scope name should have matched the regexp");
                 var index = +parsedIndexMatch[1];
                 ts.Debug.assert(isFinite(index), "Expected to parse a finite number from the scope index");
-                var extractions = getPossibleExtractions(targetRange, context, index);
-                ts.Debug.assert(extractions !== undefined, "The extraction went missing? How?");
-                return ({ edits: extractions[0].changes });
+                return getExtractionAtIndex(targetRange, context, index);
             }
             var Messages;
             (function (Messages) {
@@ -74639,7 +74640,7 @@ var ts;
                 RangeFacts[RangeFacts["IsAsyncFunction"] = 4] = "IsAsyncFunction";
                 RangeFacts[RangeFacts["UsesThis"] = 8] = "UsesThis";
                 RangeFacts[RangeFacts["InStaticRegion"] = 16] = "InStaticRegion";
-            })(RangeFacts = extractMethod_1.RangeFacts || (extractMethod_1.RangeFacts = {}));
+            })(RangeFacts || (RangeFacts = {}));
             function getRangeToExtract(sourceFile, span) {
                 var length = span.length || 0;
                 var start = getParentNodeInSpan(ts.getTokenAtPosition(sourceFile, span.start, false), sourceFile, span);
@@ -74879,7 +74880,7 @@ var ts;
                 return undefined;
             }
             function isValidExtractionTarget(node) {
-                return (node.kind === 228) || ts.isSourceFile(node) || isModuleBlock(node) || ts.isClassLike(node);
+                return (node.kind === 228) || ts.isSourceFile(node) || ts.isModuleBlock(node) || ts.isClassLike(node);
             }
             function collectEnclosingScopes(range) {
                 var current = isReadonlyArray(range.range) ? ts.firstOrUndefined(range.range) : range.range;
@@ -74904,9 +74905,21 @@ var ts;
                 }
                 return scopes;
             }
-            extractMethod_1.collectEnclosingScopes = collectEnclosingScopes;
-            function getPossibleExtractions(targetRange, context, requestedChangesIndex) {
-                if (requestedChangesIndex === void 0) { requestedChangesIndex = undefined; }
+            function getExtractionAtIndex(targetRange, context, requestedChangesIndex) {
+                var _a = getPossibleExtractionsWorker(targetRange, context), scopes = _a.scopes, _b = _a.readsAndWrites, target = _b.target, usagesPerScope = _b.usagesPerScope, errorsPerScope = _b.errorsPerScope;
+                ts.Debug.assert(!errorsPerScope[requestedChangesIndex].length, "The extraction went missing? How?");
+                context.cancellationToken.throwIfCancellationRequested();
+                return extractFunctionInScope(target, scopes[requestedChangesIndex], usagesPerScope[requestedChangesIndex], targetRange, context);
+            }
+            extractMethod_1.getExtractionAtIndex = getExtractionAtIndex;
+            function getPossibleExtractions(targetRange, context) {
+                var extractions = getPossibleExtractionsWorker(targetRange, context);
+                return extractions && extractions.scopes.map(function (scope, i) {
+                    return ({ scopeDescription: getDescriptionForScope(scope), errors: extractions.readsAndWrites.errorsPerScope[i] });
+                });
+            }
+            extractMethod_1.getPossibleExtractions = getPossibleExtractions;
+            function getPossibleExtractionsWorker(targetRange, context) {
                 var sourceFile = context.file;
                 if (targetRange === undefined) {
                     return undefined;
@@ -74916,29 +74929,9 @@ var ts;
                     return undefined;
                 }
                 var enclosingTextRange = getEnclosingTextRange(targetRange, sourceFile);
-                var _a = collectReadsAndWrites(targetRange, scopes, enclosingTextRange, sourceFile, context.program.getTypeChecker()), target = _a.target, usagesPerScope = _a.usagesPerScope, errorsPerScope = _a.errorsPerScope;
-                context.cancellationToken.throwIfCancellationRequested();
-                if (requestedChangesIndex !== undefined) {
-                    if (errorsPerScope[requestedChangesIndex].length) {
-                        return undefined;
-                    }
-                    return [extractFunctionInScope(target, scopes[requestedChangesIndex], usagesPerScope[requestedChangesIndex], targetRange, context)];
-                }
-                else {
-                    return scopes.map(function (scope, i) {
-                        var errors = errorsPerScope[i];
-                        if (errors.length) {
-                            return {
-                                scope: scope,
-                                scopeDescription: getDescriptionForScope(scope),
-                                errors: errors
-                            };
-                        }
-                        return { scope: scope, scopeDescription: getDescriptionForScope(scope) };
-                    });
-                }
+                var readsAndWrites = collectReadsAndWrites(targetRange, scopes, enclosingTextRange, sourceFile, context.program.getTypeChecker());
+                return { scopes: scopes, readsAndWrites: readsAndWrites };
             }
-            extractMethod_1.getPossibleExtractions = getPossibleExtractions;
             function getDescriptionForScope(scope) {
                 if (ts.isFunctionLike(scope)) {
                     switch (scope.kind) {
@@ -74960,7 +74953,7 @@ var ts;
                             return "'set " + scope.name.getText() + "'";
                     }
                 }
-                else if (isModuleBlock(scope)) {
+                else if (ts.isModuleBlock(scope)) {
                     return "namespace '" + scope.parent.name.getText() + "'";
                 }
                 else if (ts.isClassLike(scope)) {
@@ -74977,14 +74970,10 @@ var ts;
                     return "unknown";
                 }
             }
-            function getUniqueName(isNameOkay) {
+            function getUniqueName(fileText) {
                 var functionNameText = "newFunction";
-                if (isNameOkay(functionNameText)) {
-                    return functionNameText;
-                }
-                var i = 1;
-                while (!isNameOkay(functionNameText = "newFunction_" + i)) {
-                    i++;
+                for (var i = 1; fileText.indexOf(functionNameText) !== -1; i++) {
+                    functionNameText = "newFunction_" + i;
                 }
                 return functionNameText;
             }
@@ -74992,10 +74981,9 @@ var ts;
                 var usagesInScope = _a.usages, substitutions = _a.substitutions;
                 var checker = context.program.getTypeChecker();
                 var file = scope.getSourceFile();
-                var functionNameText = getUniqueName(function (n) { return !file.identifiers.has(n); });
+                var functionNameText = getUniqueName(file.text);
                 var isJS = ts.isInJavaScriptFile(scope);
                 var functionName = ts.createIdentifier(functionNameText);
-                var functionReference = ts.createIdentifier(functionNameText);
                 var returnType = undefined;
                 var parameters = [];
                 var callArguments = [];
@@ -75018,7 +75006,7 @@ var ts;
                     var contextualType = checker.getContextualType(node);
                     returnType = checker.typeToTypeNode(contextualType);
                 }
-                var _b = transformFunctionBody(node), body = _b.body, returnValueProperty = _b.returnValueProperty;
+                var _b = transformFunctionBody(node, writes, substitutions, !!(range.facts & RangeFacts.HasReturn)), body = _b.body, returnValueProperty = _b.returnValueProperty;
                 var newFunction;
                 if (ts.isClassLike(scope)) {
                     var modifiers = isJS ? [] : [ts.createToken(112)];
@@ -75036,7 +75024,8 @@ var ts;
                 var changeTracker = ts.textChanges.ChangeTracker.fromCodeFixContext(context);
                 changeTracker.insertNodeBefore(context.file, scope.getLastToken(), newFunction, { prefix: context.newLineCharacter, suffix: context.newLineCharacter });
                 var newNodes = [];
-                var call = ts.createCall(ts.isClassLike(scope) ? ts.createPropertyAccess(range.facts & RangeFacts.InStaticRegion ? ts.createIdentifier(scope.name.getText()) : ts.createThis(), functionReference) : functionReference, undefined, callArguments);
+                var called = getCalledExpression(scope, range, functionNameText);
+                var call = ts.createCall(called, undefined, callArguments);
                 if (range.facts & RangeFacts.IsGenerator) {
                     call = ts.createYield(ts.createToken(39), call);
                 }
@@ -75086,65 +75075,85 @@ var ts;
                 else {
                     changeTracker.replaceNodeWithNodes(context.file, range.range, newNodes, { nodeSeparator: context.newLineCharacter });
                 }
-                return {
-                    scope: scope,
-                    scopeDescription: getDescriptionForScope(scope),
-                    changes: changeTracker.getChanges()
-                };
-                function getPropertyAssignmentsForWrites(writes) {
-                    return writes.map(function (w) { return ts.createShorthandPropertyAssignment(w.symbol.name); });
-                }
-                function generateReturnValueProperty() {
-                    return "__return";
-                }
-                function transformFunctionBody(body) {
-                    if (ts.isBlock(body) && !writes && substitutions.size === 0) {
-                        return { body: ts.createBlock(body.statements, true), returnValueProperty: undefined };
-                    }
-                    var returnValueProperty;
-                    var statements = ts.createNodeArray(ts.isBlock(body) ? body.statements.slice(0) : [ts.isStatement(body) ? body : ts.createReturn(body)]);
-                    if (writes || substitutions.size) {
-                        var rewrittenStatements = ts.visitNodes(statements, visitor).slice();
-                        if (writes && !(range.facts & RangeFacts.HasReturn) && ts.isStatement(body)) {
-                            var assignments = getPropertyAssignmentsForWrites(writes);
-                            if (assignments.length === 1) {
-                                rewrittenStatements.push(ts.createReturn(assignments[0].name));
-                            }
-                            else {
-                                rewrittenStatements.push(ts.createReturn(ts.createObjectLiteral(assignments)));
-                            }
+                var edits = changeTracker.getChanges();
+                var renameRange = isReadonlyArray(range.range) ? range.range[0] : range.range;
+                var renameFilename = renameRange.getSourceFile().fileName;
+                var renameLocation = getRenameLocation(edits, renameFilename, functionNameText);
+                return { renameFilename: renameFilename, renameLocation: renameLocation, edits: edits };
+            }
+            function getRenameLocation(edits, renameFilename, functionNameText) {
+                var delta = 0;
+                for (var _i = 0, edits_1 = edits; _i < edits_1.length; _i++) {
+                    var _a = edits_1[_i], fileName = _a.fileName, textChanges_1 = _a.textChanges;
+                    ts.Debug.assert(fileName === renameFilename);
+                    for (var _b = 0, textChanges_2 = textChanges_1; _b < textChanges_2.length; _b++) {
+                        var change = textChanges_2[_b];
+                        var span_17 = change.span, newText = change.newText;
+                        var index = newText.indexOf(functionNameText);
+                        if (index !== -1) {
+                            return span_17.start + delta + index;
                         }
-                        return { body: ts.createBlock(rewrittenStatements, true), returnValueProperty: returnValueProperty };
+                        delta += newText.length - span_17.length;
                     }
-                    else {
-                        return { body: ts.createBlock(statements, true), returnValueProperty: undefined };
-                    }
-                    function visitor(node) {
-                        if (node.kind === 219 && writes) {
-                            var assignments = getPropertyAssignmentsForWrites(writes);
-                            if (node.expression) {
-                                if (!returnValueProperty) {
-                                    returnValueProperty = generateReturnValueProperty();
-                                }
-                                assignments.unshift(ts.createPropertyAssignment(returnValueProperty, ts.visitNode(node.expression, visitor)));
-                            }
-                            if (assignments.length === 1) {
-                                return ts.createReturn(assignments[0].name);
-                            }
-                            else {
-                                return ts.createReturn(ts.createObjectLiteral(assignments));
-                            }
+                }
+                throw new Error();
+            }
+            function getCalledExpression(scope, range, functionNameText) {
+                var functionReference = ts.createIdentifier(functionNameText);
+                if (ts.isClassLike(scope)) {
+                    var lhs = range.facts & RangeFacts.InStaticRegion ? ts.createIdentifier(scope.name.text) : ts.createThis();
+                    return ts.createPropertyAccess(lhs, functionReference);
+                }
+                else {
+                    return functionReference;
+                }
+            }
+            function transformFunctionBody(body, writes, substitutions, hasReturn) {
+                if (ts.isBlock(body) && !writes && substitutions.size === 0) {
+                    return { body: ts.createBlock(body.statements, true), returnValueProperty: undefined };
+                }
+                var returnValueProperty;
+                var statements = ts.createNodeArray(ts.isBlock(body) ? body.statements.slice(0) : [ts.isStatement(body) ? body : ts.createReturn(body)]);
+                if (writes || substitutions.size) {
+                    var rewrittenStatements = ts.visitNodes(statements, visitor).slice();
+                    if (writes && !hasReturn && ts.isStatement(body)) {
+                        var assignments = getPropertyAssignmentsForWrites(writes);
+                        if (assignments.length === 1) {
+                            rewrittenStatements.push(ts.createReturn(assignments[0].name));
                         }
                         else {
-                            var substitution = substitutions.get(ts.getNodeId(node).toString());
-                            return substitution || ts.visitEachChild(node, visitor, ts.nullTransformationContext);
+                            rewrittenStatements.push(ts.createReturn(ts.createObjectLiteral(assignments)));
                         }
                     }
+                    return { body: ts.createBlock(rewrittenStatements, true), returnValueProperty: returnValueProperty };
+                }
+                else {
+                    return { body: ts.createBlock(statements, true), returnValueProperty: undefined };
+                }
+                function visitor(node) {
+                    if (node.kind === 219 && writes) {
+                        var assignments = getPropertyAssignmentsForWrites(writes);
+                        if (node.expression) {
+                            if (!returnValueProperty) {
+                                returnValueProperty = "__return";
+                            }
+                            assignments.unshift(ts.createPropertyAssignment(returnValueProperty, ts.visitNode(node.expression, visitor)));
+                        }
+                        if (assignments.length === 1) {
+                            return ts.createReturn(assignments[0].name);
+                        }
+                        else {
+                            return ts.createReturn(ts.createObjectLiteral(assignments));
+                        }
+                    }
+                    else {
+                        var substitution = substitutions.get(ts.getNodeId(node).toString());
+                        return substitution || ts.visitEachChild(node, visitor, ts.nullTransformationContext);
+                    }
                 }
             }
-            extractMethod_1.extractFunctionInScope = extractFunctionInScope;
-            function isModuleBlock(n) {
-                return n.kind === 234;
+            function getPropertyAssignmentsForWrites(writes) {
+                return writes.map(function (w) { return ts.createShorthandPropertyAssignment(w.symbol.name); });
             }
             function isReadonlyArray(v) {
                 return ts.isArray(v);
@@ -77374,8 +77383,8 @@ var ts;
                 { start: start, end: end, text: text, code: code, category: category, source: source };
         }
         function allEditsBeforePos(edits, pos) {
-            for (var _i = 0, edits_1 = edits; _i < edits_1.length; _i++) {
-                var edit = edits_1[_i];
+            for (var _i = 0, edits_2 = edits; _i < edits_2.length; _i++) {
+                var edit = edits_2[_i];
                 if (ts.textSpanEnd(edit.span) >= pos) {
                     return false;
                 }
@@ -78537,12 +78546,12 @@ var ts;
                     return undefined;
                 }
                 if (simplifiedResult) {
-                    var span_17 = helpItems.applicableSpan;
+                    var span_18 = helpItems.applicableSpan;
                     return {
                         items: helpItems.items,
                         applicableSpan: {
-                            start: scriptInfo.positionToLineOffset(span_17.start),
-                            end: scriptInfo.positionToLineOffset(span_17.start + span_17.length)
+                            start: scriptInfo.positionToLineOffset(span_18.start),
+                            end: scriptInfo.positionToLineOffset(span_18.start + span_18.length)
                         },
                         selectedItemIndex: helpItems.selectedItemIndex,
                         argumentIndex: helpItems.argumentIndex,
diff --git a/lib/typescript.d.ts b/lib/typescript.d.ts
index eaf4400c8ee..4b62e695c82 100644
--- a/lib/typescript.d.ts
+++ b/lib/typescript.d.ts
@@ -3935,8 +3935,8 @@ declare namespace ts {
      */
     type RefactorEditInfo = {
         edits: FileTextChanges[];
-        renameFilename?: string;
-        renameLocation?: number;
+        renameFilename: string | undefined;
+        renameLocation: number | undefined;
     };
     interface TextInsertion {
         newText: string;
diff --git a/lib/typescript.js b/lib/typescript.js
index 7e2e649341e..74272714529 100644
--- a/lib/typescript.js
+++ b/lib/typescript.js
@@ -13845,7 +13845,8 @@ var ts;
             return token() === 24 /* DotDotDotToken */ ||
                 isIdentifierOrPattern() ||
                 ts.isModifierKind(token()) ||
-                token() === 57 /* AtToken */ || isStartOfType();
+                token() === 57 /* AtToken */ ||
+                isStartOfType(/*inStartOfParameter*/ true);
         }
         function parseParameter() {
             var node = createNode(146 /* Parameter */);
@@ -14252,7 +14253,7 @@ var ts;
                     return parseTypeReference();
             }
         }
-        function isStartOfType() {
+        function isStartOfType(inStartOfParameter) {
             switch (token()) {
                 case 119 /* AnyKeyword */:
                 case 136 /* StringKeyword */:
@@ -14279,11 +14280,11 @@ var ts;
                 case 39 /* AsteriskToken */:
                     return true;
                 case 38 /* MinusToken */:
-                    return lookAhead(nextTokenIsNumericLiteral);
+                    return !inStartOfParameter && lookAhead(nextTokenIsNumericLiteral);
                 case 19 /* OpenParenToken */:
                     // Only consider '(' the start of a type if followed by ')', '...', an identifier, a modifier,
                     // or something that starts a type. We don't want to consider things like '(1)' a type.
-                    return lookAhead(isStartOfParenthesizedOrFunctionType);
+                    return !inStartOfParameter && lookAhead(isStartOfParenthesizedOrFunctionType);
                 default:
                     return isIdentifier();
             }
@@ -89385,7 +89386,9 @@ var ts;
                     deleteCallback();
                 }
                 return {
-                    edits: changeTracker.getChanges()
+                    edits: changeTracker.getChanges(),
+                    renameFilename: undefined,
+                    renameLocation: undefined,
                 };
                 function deleteNode(node, inList) {
                     if (inList === void 0) { inList = false; }
@@ -89561,15 +89564,15 @@ var ts;
                 var usedNames = ts.createMap();
                 var i = 0;
                 for (var _i = 0, extractions_1 = extractions; _i < extractions_1.length; _i++) {
-                    var extr = extractions_1[_i];
+                    var _a = extractions_1[_i], scopeDescription = _a.scopeDescription, errors = _a.errors;
                     // Skip these since we don't have a way to report errors yet
-                    if (extr.errors && extr.errors.length) {
+                    if (errors.length) {
                         continue;
                     }
                     // Don't issue refactorings with duplicated names.
                     // Scopes come back in "innermost first" order, so extractions will
                     // preferentially go into nearer scopes
-                    var description = ts.formatStringFromArgs(ts.Diagnostics.Extract_function_into_0.message, [extr.scopeDescription]);
+                    var description = ts.formatStringFromArgs(ts.Diagnostics.Extract_function_into_0.message, [scopeDescription]);
                     if (!usedNames.has(description)) {
                         usedNames.set(description, true);
                         actions.push({
@@ -89599,10 +89602,7 @@ var ts;
                 ts.Debug.assert(!!parsedIndexMatch, "Scope name should have matched the regexp");
                 var index = +parsedIndexMatch[1];
                 ts.Debug.assert(isFinite(index), "Expected to parse a finite number from the scope index");
-                var extractions = getPossibleExtractions(targetRange, context, index);
-                // Scope is no longer valid from when the user issued the refactor (??)
-                ts.Debug.assert(extractions !== undefined, "The extraction went missing? How?");
-                return ({ edits: extractions[0].changes });
+                return getExtractionAtIndex(targetRange, context, index);
             }
             // Move these into diagnostic messages if they become user-facing
             var Messages;
@@ -89635,13 +89635,14 @@ var ts;
                  * The range is in a function which needs the 'static' modifier in a class
                  */
                 RangeFacts[RangeFacts["InStaticRegion"] = 16] = "InStaticRegion";
-            })(RangeFacts = extractMethod_1.RangeFacts || (extractMethod_1.RangeFacts = {}));
+            })(RangeFacts || (RangeFacts = {}));
             /**
              * getRangeToExtract takes a span inside a text file and returns either an expression or an array
              * of statements representing the minimum set of nodes needed to extract the entire span. This
              * process may fail, in which case a set of errors is returned instead (these are currently
              * not shown to the user, but can be used by us diagnostically)
              */
+            // exported only for tests
             function getRangeToExtract(sourceFile, span) {
                 var length = span.length || 0;
                 // Walk up starting from the the start position until we find a non-SourceFile node that subsumes the selected span.
@@ -89927,7 +89928,7 @@ var ts;
             }
             function isValidExtractionTarget(node) {
                 // Note that we don't use isFunctionLike because we don't want to put the extracted closure *inside* a method
-                return (node.kind === 228 /* FunctionDeclaration */) || ts.isSourceFile(node) || isModuleBlock(node) || ts.isClassLike(node);
+                return (node.kind === 228 /* FunctionDeclaration */) || ts.isSourceFile(node) || ts.isModuleBlock(node) || ts.isClassLike(node);
             }
             /**
              * Computes possible places we could extract the function into. For example,
@@ -89965,14 +89966,29 @@ var ts;
                 }
                 return scopes;
             }
-            extractMethod_1.collectEnclosingScopes = collectEnclosingScopes;
+            // exported only for tests
+            function getExtractionAtIndex(targetRange, context, requestedChangesIndex) {
+                var _a = getPossibleExtractionsWorker(targetRange, context), scopes = _a.scopes, _b = _a.readsAndWrites, target = _b.target, usagesPerScope = _b.usagesPerScope, errorsPerScope = _b.errorsPerScope;
+                ts.Debug.assert(!errorsPerScope[requestedChangesIndex].length, "The extraction went missing? How?");
+                context.cancellationToken.throwIfCancellationRequested();
+                return extractFunctionInScope(target, scopes[requestedChangesIndex], usagesPerScope[requestedChangesIndex], targetRange, context);
+            }
+            extractMethod_1.getExtractionAtIndex = getExtractionAtIndex;
             /**
              * Given a piece of text to extract ('targetRange'), computes a list of possible extractions.
              * Each returned ExtractResultForScope corresponds to a possible target scope and is either a set of changes
              * or an error explaining why we can't extract into that scope.
              */
-            function getPossibleExtractions(targetRange, context, requestedChangesIndex) {
-                if (requestedChangesIndex === void 0) { requestedChangesIndex = undefined; }
+            // exported only for tests
+            function getPossibleExtractions(targetRange, context) {
+                var extractions = getPossibleExtractionsWorker(targetRange, context);
+                // Need the inner type annotation to avoid https://github.com/Microsoft/TypeScript/issues/7547
+                return extractions && extractions.scopes.map(function (scope, i) {
+                    return ({ scopeDescription: getDescriptionForScope(scope), errors: extractions.readsAndWrites.errorsPerScope[i] });
+                });
+            }
+            extractMethod_1.getPossibleExtractions = getPossibleExtractions;
+            function getPossibleExtractionsWorker(targetRange, context) {
                 var sourceFile = context.file;
                 if (targetRange === undefined) {
                     return undefined;
@@ -89982,29 +89998,9 @@ var ts;
                     return undefined;
                 }
                 var enclosingTextRange = getEnclosingTextRange(targetRange, sourceFile);
-                var _a = collectReadsAndWrites(targetRange, scopes, enclosingTextRange, sourceFile, context.program.getTypeChecker()), target = _a.target, usagesPerScope = _a.usagesPerScope, errorsPerScope = _a.errorsPerScope;
-                context.cancellationToken.throwIfCancellationRequested();
-                if (requestedChangesIndex !== undefined) {
-                    if (errorsPerScope[requestedChangesIndex].length) {
-                        return undefined;
-                    }
-                    return [extractFunctionInScope(target, scopes[requestedChangesIndex], usagesPerScope[requestedChangesIndex], targetRange, context)];
-                }
-                else {
-                    return scopes.map(function (scope, i) {
-                        var errors = errorsPerScope[i];
-                        if (errors.length) {
-                            return {
-                                scope: scope,
-                                scopeDescription: getDescriptionForScope(scope),
-                                errors: errors
-                            };
-                        }
-                        return { scope: scope, scopeDescription: getDescriptionForScope(scope) };
-                    });
-                }
+                var readsAndWrites = collectReadsAndWrites(targetRange, scopes, enclosingTextRange, sourceFile, context.program.getTypeChecker());
+                return { scopes: scopes, readsAndWrites: readsAndWrites };
             }
-            extractMethod_1.getPossibleExtractions = getPossibleExtractions;
             function getDescriptionForScope(scope) {
                 if (ts.isFunctionLike(scope)) {
                     switch (scope.kind) {
@@ -90026,7 +90022,7 @@ var ts;
                             return "'set " + scope.name.getText() + "'";
                     }
                 }
-                else if (isModuleBlock(scope)) {
+                else if (ts.isModuleBlock(scope)) {
                     return "namespace '" + scope.parent.name.getText() + "'";
                 }
                 else if (ts.isClassLike(scope)) {
@@ -90043,26 +90039,25 @@ var ts;
                     return "unknown";
                 }
             }
-            function getUniqueName(isNameOkay) {
+            function getUniqueName(fileText) {
                 var functionNameText = "newFunction";
-                if (isNameOkay(functionNameText)) {
-                    return functionNameText;
-                }
-                var i = 1;
-                while (!isNameOkay(functionNameText = "newFunction_" + i)) {
-                    i++;
+                for (var i = 1; fileText.indexOf(functionNameText) !== -1; i++) {
+                    functionNameText = "newFunction_" + i;
                 }
                 return functionNameText;
             }
+            /**
+             * Result of 'extractRange' operation for a specific scope.
+             * Stores either a list of changes that should be applied to extract a range or a list of errors
+             */
             function extractFunctionInScope(node, scope, _a, range, context) {
                 var usagesInScope = _a.usages, substitutions = _a.substitutions;
                 var checker = context.program.getTypeChecker();
                 // Make a unique name for the extracted function
                 var file = scope.getSourceFile();
-                var functionNameText = getUniqueName(function (n) { return !file.identifiers.has(n); });
+                var functionNameText = getUniqueName(file.text);
                 var isJS = ts.isInJavaScriptFile(scope);
                 var functionName = ts.createIdentifier(functionNameText);
-                var functionReference = ts.createIdentifier(functionNameText);
                 var returnType = undefined;
                 var parameters = [];
                 var callArguments = [];
@@ -90093,7 +90088,7 @@ var ts;
                     var contextualType = checker.getContextualType(node);
                     returnType = checker.typeToTypeNode(contextualType);
                 }
-                var _b = transformFunctionBody(node), body = _b.body, returnValueProperty = _b.returnValueProperty;
+                var _b = transformFunctionBody(node, writes, substitutions, !!(range.facts & RangeFacts.HasReturn)), body = _b.body, returnValueProperty = _b.returnValueProperty;
                 var newFunction;
                 if (ts.isClassLike(scope)) {
                     // always create private method in TypeScript files
@@ -90119,7 +90114,8 @@ var ts;
                 changeTracker.insertNodeBefore(context.file, scope.getLastToken(), newFunction, { prefix: context.newLineCharacter, suffix: context.newLineCharacter });
                 var newNodes = [];
                 // replace range with function call
-                var call = ts.createCall(ts.isClassLike(scope) ? ts.createPropertyAccess(range.facts & RangeFacts.InStaticRegion ? ts.createIdentifier(scope.name.getText()) : ts.createThis(), functionReference) : functionReference, 
+                var called = getCalledExpression(scope, range, functionNameText);
+                var call = ts.createCall(called, 
                 /*typeArguments*/ undefined, callArguments);
                 if (range.facts & RangeFacts.IsGenerator) {
                     call = ts.createYield(ts.createToken(39 /* AsteriskToken */), call);
@@ -90176,69 +90172,92 @@ var ts;
                 else {
                     changeTracker.replaceNodeWithNodes(context.file, range.range, newNodes, { nodeSeparator: context.newLineCharacter });
                 }
-                return {
-                    scope: scope,
-                    scopeDescription: getDescriptionForScope(scope),
-                    changes: changeTracker.getChanges()
-                };
-                function getPropertyAssignmentsForWrites(writes) {
-                    return writes.map(function (w) { return ts.createShorthandPropertyAssignment(w.symbol.name); });
-                }
-                function generateReturnValueProperty() {
-                    return "__return";
-                }
-                function transformFunctionBody(body) {
-                    if (ts.isBlock(body) && !writes && substitutions.size === 0) {
-                        // already block, no writes to propagate back, no substitutions - can use node as is
-                        return { body: ts.createBlock(body.statements, /*multLine*/ true), returnValueProperty: undefined };
-                    }
-                    var returnValueProperty;
-                    var statements = ts.createNodeArray(ts.isBlock(body) ? body.statements.slice(0) : [ts.isStatement(body) ? body : ts.createReturn(body)]);
-                    // rewrite body if either there are writes that should be propagated back via return statements or there are substitutions
-                    if (writes || substitutions.size) {
-                        var rewrittenStatements = ts.visitNodes(statements, visitor).slice();
-                        if (writes && !(range.facts & RangeFacts.HasReturn) && ts.isStatement(body)) {
-                            // add return at the end to propagate writes back in case if control flow falls out of the function body
-                            // it is ok to know that range has at least one return since it we only allow unconditional returns
-                            var assignments = getPropertyAssignmentsForWrites(writes);
-                            if (assignments.length === 1) {
-                                rewrittenStatements.push(ts.createReturn(assignments[0].name));
-                            }
-                            else {
-                                rewrittenStatements.push(ts.createReturn(ts.createObjectLiteral(assignments)));
-                            }
+                var edits = changeTracker.getChanges();
+                var renameRange = isReadonlyArray(range.range) ? range.range[0] : range.range;
+                var renameFilename = renameRange.getSourceFile().fileName;
+                var renameLocation = getRenameLocation(edits, renameFilename, functionNameText);
+                return { renameFilename: renameFilename, renameLocation: renameLocation, edits: edits };
+            }
+            function getRenameLocation(edits, renameFilename, functionNameText) {
+                var delta = 0;
+                for (var _i = 0, edits_1 = edits; _i < edits_1.length; _i++) {
+                    var _a = edits_1[_i], fileName = _a.fileName, textChanges_1 = _a.textChanges;
+                    ts.Debug.assert(fileName === renameFilename);
+                    for (var _b = 0, textChanges_2 = textChanges_1; _b < textChanges_2.length; _b++) {
+                        var change = textChanges_2[_b];
+                        var span_17 = change.span, newText = change.newText;
+                        // TODO(acasey): We are assuming that the call expression comes before the function declaration,
+                        // because we want the new cursor to be on the call expression,
+                        // which is closer to where the user was before extracting the function.
+                        var index = newText.indexOf(functionNameText);
+                        if (index !== -1) {
+                            return span_17.start + delta + index;
                         }
-                        return { body: ts.createBlock(rewrittenStatements, /*multiLine*/ true), returnValueProperty: returnValueProperty };
+                        delta += newText.length - span_17.length;
                     }
-                    else {
-                        return { body: ts.createBlock(statements, /*multiLine*/ true), returnValueProperty: undefined };
-                    }
-                    function visitor(node) {
-                        if (node.kind === 219 /* ReturnStatement */ && writes) {
-                            var assignments = getPropertyAssignmentsForWrites(writes);
-                            if (node.expression) {
-                                if (!returnValueProperty) {
-                                    returnValueProperty = generateReturnValueProperty();
-                                }
-                                assignments.unshift(ts.createPropertyAssignment(returnValueProperty, ts.visitNode(node.expression, visitor)));
-                            }
-                            if (assignments.length === 1) {
-                                return ts.createReturn(assignments[0].name);
-                            }
-                            else {
-                                return ts.createReturn(ts.createObjectLiteral(assignments));
-                            }
+                }
+                throw new Error(); // Didn't find the text we inserted?
+            }
+            function getCalledExpression(scope, range, functionNameText) {
+                var functionReference = ts.createIdentifier(functionNameText);
+                if (ts.isClassLike(scope)) {
+                    var lhs = range.facts & RangeFacts.InStaticRegion ? ts.createIdentifier(scope.name.text) : ts.createThis();
+                    return ts.createPropertyAccess(lhs, functionReference);
+                }
+                else {
+                    return functionReference;
+                }
+            }
+            function transformFunctionBody(body, writes, substitutions, hasReturn) {
+                if (ts.isBlock(body) && !writes && substitutions.size === 0) {
+                    // already block, no writes to propagate back, no substitutions - can use node as is
+                    return { body: ts.createBlock(body.statements, /*multLine*/ true), returnValueProperty: undefined };
+                }
+                var returnValueProperty;
+                var statements = ts.createNodeArray(ts.isBlock(body) ? body.statements.slice(0) : [ts.isStatement(body) ? body : ts.createReturn(body)]);
+                // rewrite body if either there are writes that should be propagated back via return statements or there are substitutions
+                if (writes || substitutions.size) {
+                    var rewrittenStatements = ts.visitNodes(statements, visitor).slice();
+                    if (writes && !hasReturn && ts.isStatement(body)) {
+                        // add return at the end to propagate writes back in case if control flow falls out of the function body
+                        // it is ok to know that range has at least one return since it we only allow unconditional returns
+                        var assignments = getPropertyAssignmentsForWrites(writes);
+                        if (assignments.length === 1) {
+                            rewrittenStatements.push(ts.createReturn(assignments[0].name));
                         }
                         else {
-                            var substitution = substitutions.get(ts.getNodeId(node).toString());
-                            return substitution || ts.visitEachChild(node, visitor, ts.nullTransformationContext);
+                            rewrittenStatements.push(ts.createReturn(ts.createObjectLiteral(assignments)));
                         }
                     }
+                    return { body: ts.createBlock(rewrittenStatements, /*multiLine*/ true), returnValueProperty: returnValueProperty };
+                }
+                else {
+                    return { body: ts.createBlock(statements, /*multiLine*/ true), returnValueProperty: undefined };
+                }
+                function visitor(node) {
+                    if (node.kind === 219 /* ReturnStatement */ && writes) {
+                        var assignments = getPropertyAssignmentsForWrites(writes);
+                        if (node.expression) {
+                            if (!returnValueProperty) {
+                                returnValueProperty = "__return";
+                            }
+                            assignments.unshift(ts.createPropertyAssignment(returnValueProperty, ts.visitNode(node.expression, visitor)));
+                        }
+                        if (assignments.length === 1) {
+                            return ts.createReturn(assignments[0].name);
+                        }
+                        else {
+                            return ts.createReturn(ts.createObjectLiteral(assignments));
+                        }
+                    }
+                    else {
+                        var substitution = substitutions.get(ts.getNodeId(node).toString());
+                        return substitution || ts.visitEachChild(node, visitor, ts.nullTransformationContext);
+                    }
                 }
             }
-            extractMethod_1.extractFunctionInScope = extractFunctionInScope;
-            function isModuleBlock(n) {
-                return n.kind === 234 /* ModuleBlock */;
+            function getPropertyAssignmentsForWrites(writes) {
+                return writes.map(function (w) { return ts.createShorthandPropertyAssignment(w.symbol.name); });
             }
             function isReadonlyArray(v) {
                 return ts.isArray(v);
diff --git a/lib/typescriptServices.d.ts b/lib/typescriptServices.d.ts
index 825ed9b5c0d..d5602ea0f78 100644
--- a/lib/typescriptServices.d.ts
+++ b/lib/typescriptServices.d.ts
@@ -3935,8 +3935,8 @@ declare namespace ts {
      */
     type RefactorEditInfo = {
         edits: FileTextChanges[];
-        renameFilename?: string;
-        renameLocation?: number;
+        renameFilename: string | undefined;
+        renameLocation: number | undefined;
     };
     interface TextInsertion {
         newText: string;
diff --git a/lib/typescriptServices.js b/lib/typescriptServices.js
index 7e2e649341e..74272714529 100644
--- a/lib/typescriptServices.js
+++ b/lib/typescriptServices.js
@@ -13845,7 +13845,8 @@ var ts;
             return token() === 24 /* DotDotDotToken */ ||
                 isIdentifierOrPattern() ||
                 ts.isModifierKind(token()) ||
-                token() === 57 /* AtToken */ || isStartOfType();
+                token() === 57 /* AtToken */ ||
+                isStartOfType(/*inStartOfParameter*/ true);
         }
         function parseParameter() {
             var node = createNode(146 /* Parameter */);
@@ -14252,7 +14253,7 @@ var ts;
                     return parseTypeReference();
             }
         }
-        function isStartOfType() {
+        function isStartOfType(inStartOfParameter) {
             switch (token()) {
                 case 119 /* AnyKeyword */:
                 case 136 /* StringKeyword */:
@@ -14279,11 +14280,11 @@ var ts;
                 case 39 /* AsteriskToken */:
                     return true;
                 case 38 /* MinusToken */:
-                    return lookAhead(nextTokenIsNumericLiteral);
+                    return !inStartOfParameter && lookAhead(nextTokenIsNumericLiteral);
                 case 19 /* OpenParenToken */:
                     // Only consider '(' the start of a type if followed by ')', '...', an identifier, a modifier,
                     // or something that starts a type. We don't want to consider things like '(1)' a type.
-                    return lookAhead(isStartOfParenthesizedOrFunctionType);
+                    return !inStartOfParameter && lookAhead(isStartOfParenthesizedOrFunctionType);
                 default:
                     return isIdentifier();
             }
@@ -89385,7 +89386,9 @@ var ts;
                     deleteCallback();
                 }
                 return {
-                    edits: changeTracker.getChanges()
+                    edits: changeTracker.getChanges(),
+                    renameFilename: undefined,
+                    renameLocation: undefined,
                 };
                 function deleteNode(node, inList) {
                     if (inList === void 0) { inList = false; }
@@ -89561,15 +89564,15 @@ var ts;
                 var usedNames = ts.createMap();
                 var i = 0;
                 for (var _i = 0, extractions_1 = extractions; _i < extractions_1.length; _i++) {
-                    var extr = extractions_1[_i];
+                    var _a = extractions_1[_i], scopeDescription = _a.scopeDescription, errors = _a.errors;
                     // Skip these since we don't have a way to report errors yet
-                    if (extr.errors && extr.errors.length) {
+                    if (errors.length) {
                         continue;
                     }
                     // Don't issue refactorings with duplicated names.
                     // Scopes come back in "innermost first" order, so extractions will
                     // preferentially go into nearer scopes
-                    var description = ts.formatStringFromArgs(ts.Diagnostics.Extract_function_into_0.message, [extr.scopeDescription]);
+                    var description = ts.formatStringFromArgs(ts.Diagnostics.Extract_function_into_0.message, [scopeDescription]);
                     if (!usedNames.has(description)) {
                         usedNames.set(description, true);
                         actions.push({
@@ -89599,10 +89602,7 @@ var ts;
                 ts.Debug.assert(!!parsedIndexMatch, "Scope name should have matched the regexp");
                 var index = +parsedIndexMatch[1];
                 ts.Debug.assert(isFinite(index), "Expected to parse a finite number from the scope index");
-                var extractions = getPossibleExtractions(targetRange, context, index);
-                // Scope is no longer valid from when the user issued the refactor (??)
-                ts.Debug.assert(extractions !== undefined, "The extraction went missing? How?");
-                return ({ edits: extractions[0].changes });
+                return getExtractionAtIndex(targetRange, context, index);
             }
             // Move these into diagnostic messages if they become user-facing
             var Messages;
@@ -89635,13 +89635,14 @@ var ts;
                  * The range is in a function which needs the 'static' modifier in a class
                  */
                 RangeFacts[RangeFacts["InStaticRegion"] = 16] = "InStaticRegion";
-            })(RangeFacts = extractMethod_1.RangeFacts || (extractMethod_1.RangeFacts = {}));
+            })(RangeFacts || (RangeFacts = {}));
             /**
              * getRangeToExtract takes a span inside a text file and returns either an expression or an array
              * of statements representing the minimum set of nodes needed to extract the entire span. This
              * process may fail, in which case a set of errors is returned instead (these are currently
              * not shown to the user, but can be used by us diagnostically)
              */
+            // exported only for tests
             function getRangeToExtract(sourceFile, span) {
                 var length = span.length || 0;
                 // Walk up starting from the the start position until we find a non-SourceFile node that subsumes the selected span.
@@ -89927,7 +89928,7 @@ var ts;
             }
             function isValidExtractionTarget(node) {
                 // Note that we don't use isFunctionLike because we don't want to put the extracted closure *inside* a method
-                return (node.kind === 228 /* FunctionDeclaration */) || ts.isSourceFile(node) || isModuleBlock(node) || ts.isClassLike(node);
+                return (node.kind === 228 /* FunctionDeclaration */) || ts.isSourceFile(node) || ts.isModuleBlock(node) || ts.isClassLike(node);
             }
             /**
              * Computes possible places we could extract the function into. For example,
@@ -89965,14 +89966,29 @@ var ts;
                 }
                 return scopes;
             }
-            extractMethod_1.collectEnclosingScopes = collectEnclosingScopes;
+            // exported only for tests
+            function getExtractionAtIndex(targetRange, context, requestedChangesIndex) {
+                var _a = getPossibleExtractionsWorker(targetRange, context), scopes = _a.scopes, _b = _a.readsAndWrites, target = _b.target, usagesPerScope = _b.usagesPerScope, errorsPerScope = _b.errorsPerScope;
+                ts.Debug.assert(!errorsPerScope[requestedChangesIndex].length, "The extraction went missing? How?");
+                context.cancellationToken.throwIfCancellationRequested();
+                return extractFunctionInScope(target, scopes[requestedChangesIndex], usagesPerScope[requestedChangesIndex], targetRange, context);
+            }
+            extractMethod_1.getExtractionAtIndex = getExtractionAtIndex;
             /**
              * Given a piece of text to extract ('targetRange'), computes a list of possible extractions.
              * Each returned ExtractResultForScope corresponds to a possible target scope and is either a set of changes
              * or an error explaining why we can't extract into that scope.
              */
-            function getPossibleExtractions(targetRange, context, requestedChangesIndex) {
-                if (requestedChangesIndex === void 0) { requestedChangesIndex = undefined; }
+            // exported only for tests
+            function getPossibleExtractions(targetRange, context) {
+                var extractions = getPossibleExtractionsWorker(targetRange, context);
+                // Need the inner type annotation to avoid https://github.com/Microsoft/TypeScript/issues/7547
+                return extractions && extractions.scopes.map(function (scope, i) {
+                    return ({ scopeDescription: getDescriptionForScope(scope), errors: extractions.readsAndWrites.errorsPerScope[i] });
+                });
+            }
+            extractMethod_1.getPossibleExtractions = getPossibleExtractions;
+            function getPossibleExtractionsWorker(targetRange, context) {
                 var sourceFile = context.file;
                 if (targetRange === undefined) {
                     return undefined;
@@ -89982,29 +89998,9 @@ var ts;
                     return undefined;
                 }
                 var enclosingTextRange = getEnclosingTextRange(targetRange, sourceFile);
-                var _a = collectReadsAndWrites(targetRange, scopes, enclosingTextRange, sourceFile, context.program.getTypeChecker()), target = _a.target, usagesPerScope = _a.usagesPerScope, errorsPerScope = _a.errorsPerScope;
-                context.cancellationToken.throwIfCancellationRequested();
-                if (requestedChangesIndex !== undefined) {
-                    if (errorsPerScope[requestedChangesIndex].length) {
-                        return undefined;
-                    }
-                    return [extractFunctionInScope(target, scopes[requestedChangesIndex], usagesPerScope[requestedChangesIndex], targetRange, context)];
-                }
-                else {
-                    return scopes.map(function (scope, i) {
-                        var errors = errorsPerScope[i];
-                        if (errors.length) {
-                            return {
-                                scope: scope,
-                                scopeDescription: getDescriptionForScope(scope),
-                                errors: errors
-                            };
-                        }
-                        return { scope: scope, scopeDescription: getDescriptionForScope(scope) };
-                    });
-                }
+                var readsAndWrites = collectReadsAndWrites(targetRange, scopes, enclosingTextRange, sourceFile, context.program.getTypeChecker());
+                return { scopes: scopes, readsAndWrites: readsAndWrites };
             }
-            extractMethod_1.getPossibleExtractions = getPossibleExtractions;
             function getDescriptionForScope(scope) {
                 if (ts.isFunctionLike(scope)) {
                     switch (scope.kind) {
@@ -90026,7 +90022,7 @@ var ts;
                             return "'set " + scope.name.getText() + "'";
                     }
                 }
-                else if (isModuleBlock(scope)) {
+                else if (ts.isModuleBlock(scope)) {
                     return "namespace '" + scope.parent.name.getText() + "'";
                 }
                 else if (ts.isClassLike(scope)) {
@@ -90043,26 +90039,25 @@ var ts;
                     return "unknown";
                 }
             }
-            function getUniqueName(isNameOkay) {
+            function getUniqueName(fileText) {
                 var functionNameText = "newFunction";
-                if (isNameOkay(functionNameText)) {
-                    return functionNameText;
-                }
-                var i = 1;
-                while (!isNameOkay(functionNameText = "newFunction_" + i)) {
-                    i++;
+                for (var i = 1; fileText.indexOf(functionNameText) !== -1; i++) {
+                    functionNameText = "newFunction_" + i;
                 }
                 return functionNameText;
             }
+            /**
+             * Result of 'extractRange' operation for a specific scope.
+             * Stores either a list of changes that should be applied to extract a range or a list of errors
+             */
             function extractFunctionInScope(node, scope, _a, range, context) {
                 var usagesInScope = _a.usages, substitutions = _a.substitutions;
                 var checker = context.program.getTypeChecker();
                 // Make a unique name for the extracted function
                 var file = scope.getSourceFile();
-                var functionNameText = getUniqueName(function (n) { return !file.identifiers.has(n); });
+                var functionNameText = getUniqueName(file.text);
                 var isJS = ts.isInJavaScriptFile(scope);
                 var functionName = ts.createIdentifier(functionNameText);
-                var functionReference = ts.createIdentifier(functionNameText);
                 var returnType = undefined;
                 var parameters = [];
                 var callArguments = [];
@@ -90093,7 +90088,7 @@ var ts;
                     var contextualType = checker.getContextualType(node);
                     returnType = checker.typeToTypeNode(contextualType);
                 }
-                var _b = transformFunctionBody(node), body = _b.body, returnValueProperty = _b.returnValueProperty;
+                var _b = transformFunctionBody(node, writes, substitutions, !!(range.facts & RangeFacts.HasReturn)), body = _b.body, returnValueProperty = _b.returnValueProperty;
                 var newFunction;
                 if (ts.isClassLike(scope)) {
                     // always create private method in TypeScript files
@@ -90119,7 +90114,8 @@ var ts;
                 changeTracker.insertNodeBefore(context.file, scope.getLastToken(), newFunction, { prefix: context.newLineCharacter, suffix: context.newLineCharacter });
                 var newNodes = [];
                 // replace range with function call
-                var call = ts.createCall(ts.isClassLike(scope) ? ts.createPropertyAccess(range.facts & RangeFacts.InStaticRegion ? ts.createIdentifier(scope.name.getText()) : ts.createThis(), functionReference) : functionReference, 
+                var called = getCalledExpression(scope, range, functionNameText);
+                var call = ts.createCall(called, 
                 /*typeArguments*/ undefined, callArguments);
                 if (range.facts & RangeFacts.IsGenerator) {
                     call = ts.createYield(ts.createToken(39 /* AsteriskToken */), call);
@@ -90176,69 +90172,92 @@ var ts;
                 else {
                     changeTracker.replaceNodeWithNodes(context.file, range.range, newNodes, { nodeSeparator: context.newLineCharacter });
                 }
-                return {
-                    scope: scope,
-                    scopeDescription: getDescriptionForScope(scope),
-                    changes: changeTracker.getChanges()
-                };
-                function getPropertyAssignmentsForWrites(writes) {
-                    return writes.map(function (w) { return ts.createShorthandPropertyAssignment(w.symbol.name); });
-                }
-                function generateReturnValueProperty() {
-                    return "__return";
-                }
-                function transformFunctionBody(body) {
-                    if (ts.isBlock(body) && !writes && substitutions.size === 0) {
-                        // already block, no writes to propagate back, no substitutions - can use node as is
-                        return { body: ts.createBlock(body.statements, /*multLine*/ true), returnValueProperty: undefined };
-                    }
-                    var returnValueProperty;
-                    var statements = ts.createNodeArray(ts.isBlock(body) ? body.statements.slice(0) : [ts.isStatement(body) ? body : ts.createReturn(body)]);
-                    // rewrite body if either there are writes that should be propagated back via return statements or there are substitutions
-                    if (writes || substitutions.size) {
-                        var rewrittenStatements = ts.visitNodes(statements, visitor).slice();
-                        if (writes && !(range.facts & RangeFacts.HasReturn) && ts.isStatement(body)) {
-                            // add return at the end to propagate writes back in case if control flow falls out of the function body
-                            // it is ok to know that range has at least one return since it we only allow unconditional returns
-                            var assignments = getPropertyAssignmentsForWrites(writes);
-                            if (assignments.length === 1) {
-                                rewrittenStatements.push(ts.createReturn(assignments[0].name));
-                            }
-                            else {
-                                rewrittenStatements.push(ts.createReturn(ts.createObjectLiteral(assignments)));
-                            }
+                var edits = changeTracker.getChanges();
+                var renameRange = isReadonlyArray(range.range) ? range.range[0] : range.range;
+                var renameFilename = renameRange.getSourceFile().fileName;
+                var renameLocation = getRenameLocation(edits, renameFilename, functionNameText);
+                return { renameFilename: renameFilename, renameLocation: renameLocation, edits: edits };
+            }
+            function getRenameLocation(edits, renameFilename, functionNameText) {
+                var delta = 0;
+                for (var _i = 0, edits_1 = edits; _i < edits_1.length; _i++) {
+                    var _a = edits_1[_i], fileName = _a.fileName, textChanges_1 = _a.textChanges;
+                    ts.Debug.assert(fileName === renameFilename);
+                    for (var _b = 0, textChanges_2 = textChanges_1; _b < textChanges_2.length; _b++) {
+                        var change = textChanges_2[_b];
+                        var span_17 = change.span, newText = change.newText;
+                        // TODO(acasey): We are assuming that the call expression comes before the function declaration,
+                        // because we want the new cursor to be on the call expression,
+                        // which is closer to where the user was before extracting the function.
+                        var index = newText.indexOf(functionNameText);
+                        if (index !== -1) {
+                            return span_17.start + delta + index;
                         }
-                        return { body: ts.createBlock(rewrittenStatements, /*multiLine*/ true), returnValueProperty: returnValueProperty };
+                        delta += newText.length - span_17.length;
                     }
-                    else {
-                        return { body: ts.createBlock(statements, /*multiLine*/ true), returnValueProperty: undefined };
-                    }
-                    function visitor(node) {
-                        if (node.kind === 219 /* ReturnStatement */ && writes) {
-                            var assignments = getPropertyAssignmentsForWrites(writes);
-                            if (node.expression) {
-                                if (!returnValueProperty) {
-                                    returnValueProperty = generateReturnValueProperty();
-                                }
-                                assignments.unshift(ts.createPropertyAssignment(returnValueProperty, ts.visitNode(node.expression, visitor)));
-                            }
-                            if (assignments.length === 1) {
-                                return ts.createReturn(assignments[0].name);
-                            }
-                            else {
-                                return ts.createReturn(ts.createObjectLiteral(assignments));
-                            }
+                }
+                throw new Error(); // Didn't find the text we inserted?
+            }
+            function getCalledExpression(scope, range, functionNameText) {
+                var functionReference = ts.createIdentifier(functionNameText);
+                if (ts.isClassLike(scope)) {
+                    var lhs = range.facts & RangeFacts.InStaticRegion ? ts.createIdentifier(scope.name.text) : ts.createThis();
+                    return ts.createPropertyAccess(lhs, functionReference);
+                }
+                else {
+                    return functionReference;
+                }
+            }
+            function transformFunctionBody(body, writes, substitutions, hasReturn) {
+                if (ts.isBlock(body) && !writes && substitutions.size === 0) {
+                    // already block, no writes to propagate back, no substitutions - can use node as is
+                    return { body: ts.createBlock(body.statements, /*multLine*/ true), returnValueProperty: undefined };
+                }
+                var returnValueProperty;
+                var statements = ts.createNodeArray(ts.isBlock(body) ? body.statements.slice(0) : [ts.isStatement(body) ? body : ts.createReturn(body)]);
+                // rewrite body if either there are writes that should be propagated back via return statements or there are substitutions
+                if (writes || substitutions.size) {
+                    var rewrittenStatements = ts.visitNodes(statements, visitor).slice();
+                    if (writes && !hasReturn && ts.isStatement(body)) {
+                        // add return at the end to propagate writes back in case if control flow falls out of the function body
+                        // it is ok to know that range has at least one return since it we only allow unconditional returns
+                        var assignments = getPropertyAssignmentsForWrites(writes);
+                        if (assignments.length === 1) {
+                            rewrittenStatements.push(ts.createReturn(assignments[0].name));
                         }
                         else {
-                            var substitution = substitutions.get(ts.getNodeId(node).toString());
-                            return substitution || ts.visitEachChild(node, visitor, ts.nullTransformationContext);
+                            rewrittenStatements.push(ts.createReturn(ts.createObjectLiteral(assignments)));
                         }
                     }
+                    return { body: ts.createBlock(rewrittenStatements, /*multiLine*/ true), returnValueProperty: returnValueProperty };
+                }
+                else {
+                    return { body: ts.createBlock(statements, /*multiLine*/ true), returnValueProperty: undefined };
+                }
+                function visitor(node) {
+                    if (node.kind === 219 /* ReturnStatement */ && writes) {
+                        var assignments = getPropertyAssignmentsForWrites(writes);
+                        if (node.expression) {
+                            if (!returnValueProperty) {
+                                returnValueProperty = "__return";
+                            }
+                            assignments.unshift(ts.createPropertyAssignment(returnValueProperty, ts.visitNode(node.expression, visitor)));
+                        }
+                        if (assignments.length === 1) {
+                            return ts.createReturn(assignments[0].name);
+                        }
+                        else {
+                            return ts.createReturn(ts.createObjectLiteral(assignments));
+                        }
+                    }
+                    else {
+                        var substitution = substitutions.get(ts.getNodeId(node).toString());
+                        return substitution || ts.visitEachChild(node, visitor, ts.nullTransformationContext);
+                    }
                 }
             }
-            extractMethod_1.extractFunctionInScope = extractFunctionInScope;
-            function isModuleBlock(n) {
-                return n.kind === 234 /* ModuleBlock */;
+            function getPropertyAssignmentsForWrites(writes) {
+                return writes.map(function (w) { return ts.createShorthandPropertyAssignment(w.symbol.name); });
             }
             function isReadonlyArray(v) {
                 return ts.isArray(v);
diff --git a/lib/typingsInstaller.js b/lib/typingsInstaller.js
index 2da644fe8b8..2c2ccfdcf1f 100644
--- a/lib/typingsInstaller.js
+++ b/lib/typingsInstaller.js
@@ -11098,7 +11098,8 @@ var ts;
             return token() === 24 ||
                 isIdentifierOrPattern() ||
                 ts.isModifierKind(token()) ||
-                token() === 57 || isStartOfType();
+                token() === 57 ||
+                isStartOfType(true);
         }
         function parseParameter() {
             var node = createNode(146);
@@ -11437,7 +11438,7 @@ var ts;
                     return parseTypeReference();
             }
         }
-        function isStartOfType() {
+        function isStartOfType(inStartOfParameter) {
             switch (token()) {
                 case 119:
                 case 136:
@@ -11464,9 +11465,9 @@ var ts;
                 case 39:
                     return true;
                 case 38:
-                    return lookAhead(nextTokenIsNumericLiteral);
+                    return !inStartOfParameter && lookAhead(nextTokenIsNumericLiteral);
                 case 19:
-                    return lookAhead(isStartOfParenthesizedOrFunctionType);
+                    return !inStartOfParameter && lookAhead(isStartOfParenthesizedOrFunctionType);
                 default:
                     return isIdentifier();
             }