Merge branch 'master' of https://github.com/Microsoft/TypeScript into fixLargeProjectTry2

Author: zhengbli

src/compiler/checker.ts

@@ -1444,12 +1444,6 @@ namespace ts {
                             return result;
                         }
                         break;
-                    case SyntaxKind.ClassDeclaration:
-                    case SyntaxKind.InterfaceDeclaration:
-                        if (result = callback(getSymbolOfNode(location).members)) {
-                            return result;
-                        }
-                        break;
                 }
             }
 
@@ -1515,7 +1509,9 @@ namespace ts {
             }
 
             if (symbol) {
-                return forEachSymbolTableInScope(enclosingDeclaration, getAccessibleSymbolChainFromSymbolTable);
+                if (!(isPropertyOrMethodDeclarationSymbol(symbol))) {
+                    return forEachSymbolTableInScope(enclosingDeclaration, getAccessibleSymbolChainFromSymbolTable);
+                }
             }
         }
 
@@ -1548,6 +1544,24 @@ namespace ts {
             return qualify;
         }
 
+        function isPropertyOrMethodDeclarationSymbol(symbol: Symbol) {
+            if (symbol.declarations && symbol.declarations.length) {
+                for (const declaration of symbol.declarations) {
+                    switch (declaration.kind) {
+                        case SyntaxKind.PropertyDeclaration:
+                        case SyntaxKind.MethodDeclaration:
+                        case SyntaxKind.GetAccessor:
+                        case SyntaxKind.SetAccessor:
+                            continue;
+                        default:
+                            return false;
+                    }
+                }
+                return true;
+            }
+            return false;
+        }
+
         function isSymbolAccessible(symbol: Symbol, enclosingDeclaration: Node, meaning: SymbolFlags): SymbolAccessibilityResult {
             if (symbol && enclosingDeclaration && !(symbol.flags & SymbolFlags.TypeParameter)) {
                 const initialSymbol = symbol;

src/compiler/emitter.ts

@@ -4218,12 +4218,31 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
 
             function emitVariableDeclaration(node: VariableDeclaration) {
                 if (isBindingPattern(node.name)) {
-                    if (languageVersion < ScriptTarget.ES6) {
-                        emitDestructuring(node, /*isAssignmentExpressionStatement*/ false);
-                    }
-                    else {
+                    const isExported = getCombinedNodeFlags(node) & NodeFlags.Export;
+                    if (languageVersion >= ScriptTarget.ES6 && (!isExported || modulekind === ModuleKind.ES6)) {
+                        // emit ES6 destructuring only if target module is ES6 or variable is not exported
+                        // exported variables in CJS/AMD are prefixed with 'exports.' so result javascript { exports.toString } = 1; is illegal
+
+                        const isTopLevelDeclarationInSystemModule =
+                            modulekind === ModuleKind.System &&
+                            shouldHoistVariable(node, /*checkIfSourceFileLevelDecl*/true);
+
+                        if (isTopLevelDeclarationInSystemModule) {
+                            // In System modules top level variables are hoisted
+                            // so variable declarations with destructuring are turned into destructuring assignments.
+                            // As a result, they will need parentheses to disambiguate object binding assignments from blocks.
+                            write("(");
+                        }
+
                         emit(node.name);
                         emitOptional(" = ", node.initializer);
+
+                        if (isTopLevelDeclarationInSystemModule) {
+                            write(")");
+                        }
+                    }
+                    else {
+                        emitDestructuring(node, /*isAssignmentExpressionStatement*/ false);
                     }
                 }
                 else {
@@ -5278,9 +5297,11 @@ const _super = (function (geti, seti) {
 
             function emitClassLikeDeclarationForES6AndHigher(node: ClassLikeDeclaration) {
                 let decoratedClassAlias: string;
-                const thisNodeIsDecorated = nodeIsDecorated(node);
+                const isHoistedDeclarationInSystemModule = shouldHoistDeclarationInSystemJsModule(node);
+                const isDecorated = nodeIsDecorated(node);
+                const rewriteAsClassExpression = isDecorated || isHoistedDeclarationInSystemModule;
                 if (node.kind === SyntaxKind.ClassDeclaration) {
-                    if (thisNodeIsDecorated) {
+                    if (rewriteAsClassExpression) {
                         // When we emit an ES6 class that has a class decorator, we must tailor the
                         // emit to certain specific cases.
                         //
@@ -5361,7 +5382,10 @@ const _super = (function (geti, seti) {
                         //  [Example 4]
                         //
 
-                        if (resolver.getNodeCheckFlags(node) & NodeCheckFlags.ClassWithBodyScopedClassBinding) {
+                        // NOTE: we reuse the same rewriting logic for cases when targeting ES6 and module kind is System.
+                        // Because of hoisting top level class declaration need to be emitted as class expressions. 
+                        // Double bind case is only required if node is decorated.
+                        if (isDecorated && resolver.getNodeCheckFlags(node) & NodeCheckFlags.ClassWithBodyScopedClassBinding) {
                             decoratedClassAlias = unescapeIdentifier(makeUniqueName(node.name ? node.name.text : "default"));
                             decoratedClassAliases[getNodeId(node)] = decoratedClassAlias;
                             write(`let ${decoratedClassAlias};`);
@@ -5372,7 +5396,9 @@ const _super = (function (geti, seti) {
                             write("export ");
                         }
 
-                        write("let ");
+                        if (!isHoistedDeclarationInSystemModule) {
+                            write("let ");
+                        }
                         emitDeclarationName(node);
                         if (decoratedClassAlias !== undefined) {
                             write(` = ${decoratedClassAlias}`);
@@ -5416,7 +5442,7 @@ const _super = (function (geti, seti) {
                 // emit name if
                 // - node has a name
                 // - this is default export with static initializers
-                if (node.name || (node.flags & NodeFlags.Default && (staticProperties.length > 0 || modulekind !== ModuleKind.ES6) && !thisNodeIsDecorated)) {
+                if (node.name || (node.flags & NodeFlags.Default && (staticProperties.length > 0 || modulekind !== ModuleKind.ES6) && !rewriteAsClassExpression)) {
                     write(" ");
                     emitDeclarationName(node);
                 }
@@ -5436,7 +5462,7 @@ const _super = (function (geti, seti) {
                 writeLine();
                 emitToken(SyntaxKind.CloseBraceToken, node.members.end);
 
-                if (thisNodeIsDecorated) {
+                if (rewriteAsClassExpression) {
                     decoratedClassAliases[getNodeId(node)] = undefined;
                     write(";");
                 }
@@ -5476,7 +5502,7 @@ const _super = (function (geti, seti) {
                     // module), export it
                     if (node.flags & NodeFlags.Default) {
                         // if this is a top level default export of decorated class, write the export after the declaration.
-                        if (thisNodeIsDecorated) {
+                        if (isDecorated) {
                             writeLine();
                             write("export default ");
                             emitDeclarationName(node);

src/services/services.ts

@@ -3505,7 +3505,18 @@ namespace ts {
                         // We don't want to complete using the type acquired by the shape
                         // of the binding pattern; we are only interested in types acquired
                         // through type declaration or inference.
-                        if (rootDeclaration.initializer || rootDeclaration.type) {
+                        // Also proceed if rootDeclaration is parameter and if its containing function expression\arrow function is contextually typed -
+                        // type of parameter will flow in from the contextual type of the function
+                        let canGetType = !!(rootDeclaration.initializer || rootDeclaration.type);
+                        if (!canGetType && rootDeclaration.kind === SyntaxKind.Parameter) {
+                            if (isExpression(rootDeclaration.parent)) {
+                                canGetType = !!typeChecker.getContextualType(<Expression>rootDeclaration.parent);
+                            }
+                            else if (rootDeclaration.parent.kind === SyntaxKind.MethodDeclaration || rootDeclaration.parent.kind === SyntaxKind.SetAccessor) {
+                                canGetType = isExpression(rootDeclaration.parent.parent) && !!typeChecker.getContextualType(<Expression>rootDeclaration.parent.parent);
+                            }
+                        }
+                        if (canGetType) {
                             typeForObject = typeChecker.getTypeAtLocation(objectLikeContainer);
                             existingMembers = (<BindingPattern>objectLikeContainer).elements;
                         }