TypeScript/src/compiler/binder.ts

/// <reference path="parser.ts"/>

/* @internal */
module ts {
    export let bindTime = 0;

    export const enum ModuleInstanceState {
        NonInstantiated = 0,
        Instantiated    = 1,
        ConstEnumOnly   = 2
    }

    export function getModuleInstanceState(node: Node): ModuleInstanceState {
        // A module is uninstantiated if it contains only 
        // 1. interface declarations, type alias declarations
        if (node.kind === SyntaxKind.InterfaceDeclaration || node.kind === SyntaxKind.TypeAliasDeclaration) {
            return ModuleInstanceState.NonInstantiated;
        }
        // 2. const enum declarations
        else if (isConstEnumDeclaration(node)) {
            return ModuleInstanceState.ConstEnumOnly;
        }
        // 3. non-exported import declarations
        else if ((node.kind === SyntaxKind.ImportDeclaration || node.kind === SyntaxKind.ImportEqualsDeclaration) && !(node.flags & NodeFlags.Export)) {
            return ModuleInstanceState.NonInstantiated;
        }
        // 4. other uninstantiated module declarations.
        else if (node.kind === SyntaxKind.ModuleBlock) {
            let state = ModuleInstanceState.NonInstantiated;
            forEachChild(node, n => {
                switch (getModuleInstanceState(n)) {
                    case ModuleInstanceState.NonInstantiated:
                        // child is non-instantiated - continue searching
                        return false;
                    case ModuleInstanceState.ConstEnumOnly:
                        // child is const enum only - record state and continue searching
                        state = ModuleInstanceState.ConstEnumOnly;
                        return false;
                    case ModuleInstanceState.Instantiated:
                        // child is instantiated - record state and stop
                        state = ModuleInstanceState.Instantiated;
                        return true;
                }
            });
            return state;
        }
        else if (node.kind === SyntaxKind.ModuleDeclaration) {
            return getModuleInstanceState((<ModuleDeclaration>node).body);
        }
        else {
            return ModuleInstanceState.Instantiated;
        }
    }

    export function bindSourceFile(file: SourceFile): void {
        let start = new Date().getTime();
        bindSourceFileWorker(file);
        bindTime += new Date().getTime() - start;
    }

    function bindSourceFileWorker(file: SourceFile): void {
        let parent: Node;
        let container: Node;
        let blockScopeContainer: Node;
        let lastContainer: Node;
        let symbolCount = 0;
        let Symbol = objectAllocator.getSymbolConstructor();

        if (!file.locals) {
            file.locals = {};
            container = blockScopeContainer = file;
            bind(file);
            file.symbolCount = symbolCount;
        }

        function createSymbol(flags: SymbolFlags, name: string): Symbol {
            symbolCount++;
            return new Symbol(flags, name);
        }

        function addDeclarationToSymbol(symbol: Symbol, node: Declaration, symbolFlags: SymbolFlags) {
            symbol.flags |= symbolFlags;

            node.symbol = symbol;
            if (symbolFlags & SymbolFlags.HasLocals) {
                node.locals = {};
            }

            if (!symbol.declarations) {
                symbol.declarations = [];
            }
            symbol.declarations.push(node);

            if (symbolFlags & SymbolFlags.HasExports && !symbol.exports) {
                symbol.exports = {};
            }

            if (symbolFlags & SymbolFlags.HasMembers && !symbol.members) {
                symbol.members = {};
            }

            if (symbolFlags & SymbolFlags.Value && !symbol.valueDeclaration) {
                symbol.valueDeclaration = node;
            }
        }

        // Should not be called on a declaration with a computed property name,
        // unless it is a well known Symbol.
        function getDeclarationName(node: Declaration): string {
            if (node.name) {
                if (node.kind === SyntaxKind.ModuleDeclaration && node.name.kind === SyntaxKind.StringLiteral) {
                    return '"' + (<LiteralExpression>node.name).text + '"';
                }
                if (node.name.kind === SyntaxKind.ComputedPropertyName) {
                    let nameExpression = (<ComputedPropertyName>node.name).expression;
                    Debug.assert(isWellKnownSymbolSyntactically(nameExpression));
                    return getPropertyNameForKnownSymbolName((<PropertyAccessExpression>nameExpression).name.text);
                }
                return (<Identifier | LiteralExpression>node.name).text;
            }
            switch (node.kind) {
                case SyntaxKind.Constructor:
                    return "__constructor";
                case SyntaxKind.FunctionType:
                case SyntaxKind.CallSignature:
                    return "__call";
                case SyntaxKind.ConstructorType:
                case SyntaxKind.ConstructSignature:
                    return "__new";
                case SyntaxKind.IndexSignature:
                    return "__index";
                case SyntaxKind.ExportDeclaration:
                    return "__export";
                case SyntaxKind.ExportAssignment:
                    return (<ExportAssignment>node).isExportEquals ? "export=" : "default";
                case SyntaxKind.FunctionDeclaration:
                case SyntaxKind.ClassDeclaration:
                    return node.flags & NodeFlags.Default ? "default" : undefined;
            }
        }

        function getDisplayName(node: Declaration): string {
            return node.name ? declarationNameToString(node.name) : getDeclarationName(node);
        }

        function declareSymbol(symbolTable: SymbolTable, parent: Symbol, node: Declaration, includes: SymbolFlags, excludes: SymbolFlags): Symbol {
            Debug.assert(!hasDynamicName(node));

            // The exported symbol for an export default function/class node is always named "default"
            let name = node.flags & NodeFlags.Default && parent ? "default" : getDeclarationName(node);

            let symbol: Symbol;
            if (name !== undefined) {
                // Check and see if the symbol table already has a symbol with this name.  If not,
                // create a new symbol with this name and add it to the table.  Note that we don't
                // give the new symbol any flags *yet*.  This ensures that it will not conflict 
                // witht he 'excludes' flags we pass in.
                //
                // If we do get an existing symbol, see if it conflicts with the new symbol we're
                // creating.  For example, a 'var' symbol and a 'class' symbol will conflict within
                // the same symbol table.  If we have a conflict, report the issue on each 
                // declaration we have for this symbol, and then create a new symbol for this 
                // declaration.
                //
                // If we created a new symbol, either because we didn't have a symbol with this name
                // in the symbol table, or we conflicted with an existing symbol, then just add this
                // node as the sole declaration of the new symbol.
                //
                // Otherwise, we'll be merging into a compatible existing symbol (for example when
                // you have multiple 'vars' with the same name in the same container).  In this case
                // just add this node into the declarations list of the symbol.
                symbol = hasProperty(symbolTable, name)
                    ? symbolTable[name]
                    : (symbolTable[name] = createSymbol(SymbolFlags.None, name));
                if (symbol.flags & excludes) {
                    if (node.name) {
                        node.name.parent = node;
                    }

                    // Report errors every position with duplicate declaration
                    // Report errors on previous encountered declarations
                    let message = symbol.flags & SymbolFlags.BlockScopedVariable
                        ? Diagnostics.Cannot_redeclare_block_scoped_variable_0
                        : Diagnostics.Duplicate_identifier_0;
                    forEach(symbol.declarations, declaration => {
                        file.bindDiagnostics.push(createDiagnosticForNode(declaration.name || declaration, message, getDisplayName(declaration)));
                    });
                    file.bindDiagnostics.push(createDiagnosticForNode(node.name || node, message, getDisplayName(node)));

                    symbol = createSymbol(SymbolFlags.None, name);
                }
            }
            else {
                symbol = createSymbol(SymbolFlags.None, "__missing");
            }

            addDeclarationToSymbol(symbol, node, includes);
            symbol.parent = parent;

            return symbol;
        }

        function declareModuleMember(node: Declaration, symbolFlags: SymbolFlags, symbolExcludes: SymbolFlags): Symbol {
            let hasExportModifier = getCombinedNodeFlags(node) & NodeFlags.Export;
            if (symbolFlags & SymbolFlags.Alias) {
                if (node.kind === SyntaxKind.ExportSpecifier || (node.kind === SyntaxKind.ImportEqualsDeclaration && hasExportModifier)) {
                    return declareSymbol(container.symbol.exports, container.symbol, node, symbolFlags, symbolExcludes);
                }
                else {
                    return declareSymbol(container.locals, undefined, node, symbolFlags, symbolExcludes);
                }
            }
            else {
                // Exported module members are given 2 symbols: A local symbol that is classified with an ExportValue,
                // ExportType, or ExportContainer flag, and an associated export symbol with all the correct flags set
                // on it. There are 2 main reasons:
                //
                //   1. We treat locals and exports of the same name as mutually exclusive within a container. 
                //      That means the binder will issue a Duplicate Identifier error if you mix locals and exports
                //      with the same name in the same container.
                //      TODO: Make this a more specific error and decouple it from the exclusion logic.
                //   2. When we checkIdentifier in the checker, we set its resolved symbol to the local symbol,
                //      but return the export symbol (by calling getExportSymbolOfValueSymbolIfExported). That way
                //      when the emitter comes back to it, it knows not to qualify the name if it was found in a containing scope.
                if (hasExportModifier || container.flags & NodeFlags.ExportContext) {
                    let exportKind =
                        (symbolFlags & SymbolFlags.Value ? SymbolFlags.ExportValue : 0) |
                        (symbolFlags & SymbolFlags.Type ? SymbolFlags.ExportType : 0) |
                        (symbolFlags & SymbolFlags.Namespace ? SymbolFlags.ExportNamespace : 0);
                    let local = declareSymbol(container.locals, undefined, node, exportKind, symbolExcludes);
                    local.exportSymbol = declareSymbol(container.symbol.exports, container.symbol, node, symbolFlags, symbolExcludes);
                    node.localSymbol = local;
                    return local;
                }
                else {
                    return declareSymbol(container.locals, undefined, node, symbolFlags, symbolExcludes);
                }
            }
        }

        // All container nodes are kept on a linked list in declaration order. This list is used by the getLocalNameOfContainer function
        // in the type checker to validate that the local name used for a container is unique.
        function bindChildren(node: Node, symbolFlags: SymbolFlags) {
            let saveParent = parent;
            let saveContainer = container;
            let savedBlockScopeContainer = blockScopeContainer;
            parent = node;
            if (symbolFlags & SymbolFlags.IsContainer) {
                container = node;

                if (lastContainer) {
                    lastContainer.nextContainer = container;
                }

                lastContainer = container;
            }

            if (symbolFlags & SymbolFlags.IsBlockScopedContainer) {
                // in incremental scenarios we might reuse nodes that already have locals being allocated
                // during the bind step these locals should be dropped to prevent using stale data.
                // locals should always be dropped unless they were previously initialized by the binder
                // these cases are:
                // - node has locals (symbolKind & HasLocals) !== 0
                // - node is a source file
                blockScopeContainer = node;
                if ((symbolFlags & SymbolFlags.HasLocals) === 0 && node.kind !== SyntaxKind.SourceFile) {
                    blockScopeContainer.locals = undefined;
                }
            }

            forEachChild(node, bind);

            container = saveContainer;
            parent = saveParent;
            blockScopeContainer = savedBlockScopeContainer;
        }

        function declareSymbolAndAddToSymbolTable(node: Declaration, symbolFlags: SymbolFlags, symbolExcludes: SymbolFlags): SymbolFlags {
            declareSymbolAndAddToSymbolTableWorker(node, symbolFlags, symbolExcludes);
            return symbolFlags;
        }

        function declareSymbolAndAddToSymbolTableWorker(node: Declaration, symbolFlags: SymbolFlags, symbolExcludes: SymbolFlags): Symbol {
            switch (container.kind) {
                // Modules, source files, and classes need specialized handling for how their 
                // members are declared (for example, a member of a class will go into a specific
                // symbol table depending on if it is static or not). As such, we defer to 
                // specialized handlers to take care of declaring these child members.
                case SyntaxKind.ModuleDeclaration:
                    return declareModuleMember(node, symbolFlags, symbolExcludes);

                case SyntaxKind.SourceFile:
                    return declareSourceFileMember(node, symbolFlags, symbolExcludes);

                case SyntaxKind.ClassExpression:
                case SyntaxKind.ClassDeclaration:
                    return declareClassMember(node, symbolFlags, symbolExcludes);

                case SyntaxKind.EnumDeclaration:
                    // Enum members are always put in the 'exports' of the containing enum.
                    // They are only accessible through their container, and are never in 
                    // scope otherwise (even inside the body of the enum declaring them.).
                    return declareSymbol(container.symbol.exports, container.symbol, node, symbolFlags, symbolExcludes);

                case SyntaxKind.TypeLiteral:
                case SyntaxKind.ObjectLiteralExpression:
                case SyntaxKind.InterfaceDeclaration:
                    // Interface/Object-types always have their children added to the 'members' of
                    // their container.  They are only accessible through an instance of their 
                    // container, and are never in scope otherwise (even inside the body of the 
                    // object / type / interface declaring them).
                    return declareSymbol(container.symbol.members, container.symbol, node, symbolFlags, symbolExcludes);

                case SyntaxKind.FunctionType:
                case SyntaxKind.ConstructorType:
                case SyntaxKind.CallSignature:
                case SyntaxKind.ConstructSignature:
                case SyntaxKind.IndexSignature:
                case SyntaxKind.MethodDeclaration:
                case SyntaxKind.MethodSignature:
                case SyntaxKind.Constructor:
                case SyntaxKind.GetAccessor:
                case SyntaxKind.SetAccessor:
                case SyntaxKind.FunctionDeclaration:
                case SyntaxKind.FunctionExpression:
                case SyntaxKind.ArrowFunction:
                    // All the children of these container types are never visible through another
                    // symbol (i.e. through another symbol's 'exports' or 'members').  Instead, 
                    // more or less, they're only accessed 'lexically' (i.e. from code that exists
                    // underneath their container in the tree.  To accomplish this, we simply add
                    // their declared symbol to the 'locals' of the container.  These symbols can
                    // then be found as the type checker walks up the containers, checking them
                    // for matching names.
                    return declareSymbol(container.locals, undefined, node, symbolFlags, symbolExcludes);
            }
        }

        function declareClassMember(node: Declaration, symbolFlags: SymbolFlags, symbolExcludes: SymbolFlags) {
            return node.flags & NodeFlags.Static
                ? declareSymbol(container.symbol.exports, container.symbol, node, symbolFlags, symbolExcludes)
                : declareSymbol(container.symbol.members, container.symbol, node, symbolFlags, symbolExcludes);
        }

        function declareSourceFileMember(node: Declaration, symbolFlags: SymbolFlags, symbolExcludes: SymbolFlags) {
            return isExternalModule(file)
                ? declareModuleMember(node, symbolFlags, symbolExcludes)
                : declareSymbol(file.locals, undefined, node, symbolFlags, symbolExcludes);
        }

        function isAmbientContext(node: Node): boolean {
            while (node) {
                if (node.flags & NodeFlags.Ambient) {
                    return true;
                }

                node = node.parent;
            }
            return false;
        }

        function hasExportDeclarations(node: ModuleDeclaration | SourceFile): boolean {
            var body = node.kind === SyntaxKind.SourceFile ? node : (<ModuleDeclaration>node).body;
            if (body.kind === SyntaxKind.SourceFile || body.kind === SyntaxKind.ModuleBlock) {
                for (let stat of (<Block>body).statements) {
                    if (stat.kind === SyntaxKind.ExportDeclaration || stat.kind === SyntaxKind.ExportAssignment) {
                        return true;
                    }
                }
            }
            return false;
        }

        function setExportContextFlag(node: ModuleDeclaration | SourceFile) {
            // A declaration source file or ambient module declaration that contains no export declarations (but possibly regular
            // declarations with export modifiers) is an export context in which declarations are implicitly exported.
            if (isAmbientContext(node) && !hasExportDeclarations(node)) {
                node.flags |= NodeFlags.ExportContext;
            }
            else {
                node.flags &= ~NodeFlags.ExportContext;
            }
        }

        function bindModuleDeclaration(node: ModuleDeclaration) {
            setExportContextFlag(node);
            if (node.name.kind === SyntaxKind.StringLiteral) {
                return declareSymbolAndAddToSymbolTable(node, SymbolFlags.ValueModule, SymbolFlags.ValueModuleExcludes);
            }
            else {
                let state = getModuleInstanceState(node);
                if (state === ModuleInstanceState.NonInstantiated) {
                    return declareSymbolAndAddToSymbolTable(node, SymbolFlags.NamespaceModule, SymbolFlags.NamespaceModuleExcludes);
                }
                else {
                    let result = declareSymbolAndAddToSymbolTable(node, SymbolFlags.ValueModule, SymbolFlags.ValueModuleExcludes);

                    let currentModuleIsConstEnumOnly = state === ModuleInstanceState.ConstEnumOnly;
                    if (node.symbol.constEnumOnlyModule === undefined) {
                        // non-merged case - use the current state
                        node.symbol.constEnumOnlyModule = currentModuleIsConstEnumOnly;
                    }
                    else {
                        // merged case: module is const enum only if all its pieces are non-instantiated or const enum
                        node.symbol.constEnumOnlyModule = node.symbol.constEnumOnlyModule && currentModuleIsConstEnumOnly;
                    }

                    return result;
                }
            }
        }

        function bindFunctionOrConstructorType(node: SignatureDeclaration): SymbolFlags {
            // For a given function symbol "<...>(...) => T" we want to generate a symbol identical
            // to the one we would get for: { <...>(...): T }
            //
            // We do that by making an anonymous type literal symbol, and then setting the function 
            // symbol as its sole member. To the rest of the system, this symbol will be  indistinguishable 
            // from an actual type literal symbol you would have gotten had you used the long form.
            let name = getDeclarationName(node);
            let symbol = createSymbol(SymbolFlags.Signature, name);
            addDeclarationToSymbol(symbol, node, SymbolFlags.Signature);

            let typeLiteralSymbol = createSymbol(SymbolFlags.TypeLiteral, "__type");
            addDeclarationToSymbol(typeLiteralSymbol, node, SymbolFlags.TypeLiteral);
            typeLiteralSymbol.members = { [name]: symbol };

            return SymbolFlags.Signature;
        }

        function bindAnonymousDeclaration(node: Declaration, symbolFlags: SymbolFlags, name: string): SymbolFlags {
            let symbol = createSymbol(symbolFlags, name);
            addDeclarationToSymbol(symbol, node, symbolFlags);
            return symbolFlags;
        }

        function bindBlockScopedDeclaration(node: Declaration, symbolFlags: SymbolFlags, symbolExcludes: SymbolFlags): SymbolFlags {
            switch (blockScopeContainer.kind) {
                case SyntaxKind.ModuleDeclaration:
                    declareModuleMember(node, symbolFlags, symbolExcludes);
                    break;
                case SyntaxKind.SourceFile:
                    if (isExternalModule(<SourceFile>container)) {
                        declareModuleMember(node, symbolFlags, symbolExcludes);
                        break;
                    }
                    // fall through.
                default:
                    if (!blockScopeContainer.locals) {
                        blockScopeContainer.locals = {};
                    }
                    declareSymbol(blockScopeContainer.locals, undefined, node, symbolFlags, symbolExcludes);
            }

            return symbolFlags;
        }

        function bindBlockScopedVariableDeclaration(node: Declaration): SymbolFlags {
            return bindBlockScopedDeclaration(node, SymbolFlags.BlockScopedVariable, SymbolFlags.BlockScopedVariableExcludes);
        }

        function getDestructuringParameterName(node: Declaration) {
            return "__" + indexOf((<SignatureDeclaration>node.parent).parameters, node);
        }

        function bind(node: Node): void {
            node.parent = parent;

            // First we bind declaration nodes to a symbol if possible.  We'll both create a symbol
            // and then potentially add the symbol to an appropriate symbol table.  The symbolFlags 
            // that are returned from this help inform how we recurse into the children of this node.
            //
            // Possible destination symbol tables are:
            // 
            //  1) The 'exports' table of the current container's symbol.
            //  2) The 'members' table of the current container's symbol.
            //  3) The 'locals' table of the current container.
            //
            // However, not all symbols will end up in any of these tables.  'Anonymous' symbols 
            // (like TypeLiterals for example) will not be put in any table.
            var symbolFlags = bindWorker(node);

            // Then we recurse into the children of the node to bind them as well.  For certain 
            // symbols we do specialized work when we recurse.  For example, we'll keep track of
            // the current 'container' node when it changes.  This helps us know which symbol table
            // a local should go into for example.
            bindChildren(node, symbolFlags);
        }
        
        function bindWorker(node: Node): SymbolFlags {
            switch (node.kind) {
                case SyntaxKind.TypeParameter:
                    return declareSymbolAndAddToSymbolTable(<Declaration>node, SymbolFlags.TypeParameter, SymbolFlags.TypeParameterExcludes);
                case SyntaxKind.Parameter:
                    return bindParameter(<ParameterDeclaration>node);
                case SyntaxKind.VariableDeclaration:
                case SyntaxKind.BindingElement:
                    return bindVariableDeclarationOrBindingElement(<VariableDeclaration | BindingElement>node);
                case SyntaxKind.PropertyDeclaration:
                case SyntaxKind.PropertySignature:
                    return bindPropertyOrMethodOrAccessor(<Declaration>node, SymbolFlags.Property | ((<PropertyDeclaration>node).questionToken ? SymbolFlags.Optional : SymbolFlags.None), SymbolFlags.PropertyExcludes);
                case SyntaxKind.PropertyAssignment:
                case SyntaxKind.ShorthandPropertyAssignment:
                    return bindPropertyOrMethodOrAccessor(<Declaration>node, SymbolFlags.Property, SymbolFlags.PropertyExcludes);
                case SyntaxKind.EnumMember:
                    return bindPropertyOrMethodOrAccessor(<Declaration>node, SymbolFlags.EnumMember, SymbolFlags.EnumMemberExcludes);
                case SyntaxKind.CallSignature:
                case SyntaxKind.ConstructSignature:
                case SyntaxKind.IndexSignature:
                    return declareSymbolAndAddToSymbolTable(<Declaration>node, SymbolFlags.Signature, SymbolFlags.None);
                case SyntaxKind.MethodDeclaration:
                case SyntaxKind.MethodSignature:
                    // If this is an ObjectLiteralExpression method, then it sits in the same space
                    // as other properties in the object literal.  So we use SymbolFlags.PropertyExcludes
                    // so that it will conflict with any other object literal members with the same
                    // name.
                    return bindPropertyOrMethodOrAccessor(<Declaration>node, SymbolFlags.Method | ((<MethodDeclaration>node).questionToken ? SymbolFlags.Optional : SymbolFlags.None),
                        isObjectLiteralMethod(node) ? SymbolFlags.PropertyExcludes : SymbolFlags.MethodExcludes);
                case SyntaxKind.FunctionDeclaration:
                    return declareSymbolAndAddToSymbolTable(<Declaration>node, SymbolFlags.Function, SymbolFlags.FunctionExcludes);
                case SyntaxKind.Constructor:
                    return declareSymbolAndAddToSymbolTable(<Declaration>node, SymbolFlags.Constructor, /*symbolExcludes:*/ SymbolFlags.None);
                case SyntaxKind.GetAccessor:
                    return bindPropertyOrMethodOrAccessor(<Declaration>node, SymbolFlags.GetAccessor, SymbolFlags.GetAccessorExcludes);
                case SyntaxKind.SetAccessor:
                    return bindPropertyOrMethodOrAccessor(<Declaration>node, SymbolFlags.SetAccessor, SymbolFlags.SetAccessorExcludes);
                case SyntaxKind.FunctionType:
                case SyntaxKind.ConstructorType:
                    return bindFunctionOrConstructorType(<SignatureDeclaration>node);
                case SyntaxKind.TypeLiteral:
                    return bindAnonymousDeclaration(<TypeLiteralNode>node, SymbolFlags.TypeLiteral, "__type");
                case SyntaxKind.ObjectLiteralExpression:
                    return bindAnonymousDeclaration(<ObjectLiteralExpression>node, SymbolFlags.ObjectLiteral, "__object");
                case SyntaxKind.FunctionExpression:
                case SyntaxKind.ArrowFunction:
                    return bindAnonymousDeclaration(<FunctionExpression>node, SymbolFlags.Function, "__function");
                case SyntaxKind.ClassExpression:
                case SyntaxKind.ClassDeclaration:
                    return bindClassLikeDeclaration(<ClassLikeDeclaration>node);
                case SyntaxKind.InterfaceDeclaration:
                    return declareSymbolAndAddToSymbolTable(<Declaration>node, SymbolFlags.Interface, SymbolFlags.InterfaceExcludes);
                case SyntaxKind.TypeAliasDeclaration:
                    return declareSymbolAndAddToSymbolTable(<Declaration>node, SymbolFlags.TypeAlias, SymbolFlags.TypeAliasExcludes);
                case SyntaxKind.EnumDeclaration:
                    return bindEnumDeclaration(<EnumDeclaration>node);
                case SyntaxKind.ModuleDeclaration:
                    return bindModuleDeclaration(<ModuleDeclaration>node);
                case SyntaxKind.ImportEqualsDeclaration:
                case SyntaxKind.NamespaceImport:
                case SyntaxKind.ImportSpecifier:
                case SyntaxKind.ExportSpecifier:
                    return declareSymbolAndAddToSymbolTable(<Declaration>node, SymbolFlags.Alias, SymbolFlags.AliasExcludes);
                case SyntaxKind.ImportClause:
                    return bindImportClause(<ImportClause>node);
                case SyntaxKind.ExportDeclaration:
                    return bindExportDeclaration(<ExportDeclaration>node);
                case SyntaxKind.ExportAssignment:
                    return bindExportAssignment(<ExportAssignment>node);
                case SyntaxKind.SourceFile:
                    return bindSourceFileIfExternalModule();
                case SyntaxKind.Block:
                    // do not treat function block a block-scope container
                    // all block-scope locals that reside in this block should go to the function locals.
                    // Otherwise this won't be considered as redeclaration of a block scoped local:
                    // function foo(x) {
                    //  let x;
                    // }
                    // 'x' will be placed into the function locals and 'let x' - into the locals of the block
                    return isFunctionLike(node.parent) ? SymbolFlags.None : SymbolFlags.BlockScopedContainer;
                case SyntaxKind.CatchClause:
                case SyntaxKind.ForStatement:
                case SyntaxKind.ForInStatement:
                case SyntaxKind.ForOfStatement:
                case SyntaxKind.CaseBlock:
                    return SymbolFlags.BlockScopedContainer;
            }

            return SymbolFlags.None;
        }

        function bindSourceFileIfExternalModule() {
            setExportContextFlag(file);
            return isExternalModule(file)
                ? bindAnonymousDeclaration(file, SymbolFlags.ValueModule, '"' + removeFileExtension(file.fileName) + '"')
                : SymbolFlags.BlockScopedContainer;
        }

        function bindExportAssignment(node: ExportAssignment) {
            if (node.expression.kind === SyntaxKind.Identifier) {
                // An export default clause with an identifier exports all meanings of that identifier
                declareSymbol(container.symbol.exports, container.symbol, node, SymbolFlags.Alias, SymbolFlags.PropertyExcludes | SymbolFlags.AliasExcludes);
            }
            else {
                // An export default clause with an expression exports a value
                declareSymbol(container.symbol.exports, container.symbol, node, SymbolFlags.Property, SymbolFlags.PropertyExcludes | SymbolFlags.AliasExcludes);
            }

            return SymbolFlags.None;
        }

        function bindExportDeclaration(node: ExportDeclaration) {
            if (!node.exportClause) {
                // All export * declarations are collected in an __export symbol
                declareSymbol(container.symbol.exports, container.symbol, node, SymbolFlags.ExportStar, SymbolFlags.None);
            }
            return SymbolFlags.None;
        }

        function bindImportClause(node: ImportClause) {
            return node.name
                ? declareSymbolAndAddToSymbolTable(node, SymbolFlags.Alias, SymbolFlags.AliasExcludes)
                : SymbolFlags.None;
        }

        function bindClassLikeDeclaration(node: ClassLikeDeclaration) {
            if (node.kind === SyntaxKind.ClassDeclaration) {
                bindBlockScopedDeclaration(node, SymbolFlags.Class, SymbolFlags.ClassExcludes);
            }
            else {
                bindAnonymousDeclaration(node, SymbolFlags.Class, "__class");
            }

            let symbol = node.symbol;

            // TypeScript 1.0 spec (April 2014): 8.4
            // Every class automatically contains a static property member named 'prototype', the 
            // type of which is an instantiation of the class type with type Any supplied as a type
            // argument for each type parameter. It is an error to explicitly declare a static 
            // property member with the name 'prototype'.
            //
            // Note: we check for this here because this class may be merging into a module.  The
            // module might have an exported variable called 'prototype'.  We can't allow that as
            // that would clash with the built-in 'prototype' for the class.
            let prototypeSymbol = createSymbol(SymbolFlags.Property | SymbolFlags.Prototype, "prototype");
            if (hasProperty(symbol.exports, prototypeSymbol.name)) {
                if (node.name) {
                    node.name.parent = node;
                }
                file.bindDiagnostics.push(createDiagnosticForNode(symbol.exports[prototypeSymbol.name].declarations[0],
                    Diagnostics.Duplicate_identifier_0, prototypeSymbol.name));
            }
            symbol.exports[prototypeSymbol.name] = prototypeSymbol;
            prototypeSymbol.parent = symbol;

            return SymbolFlags.Class;
        }

        function bindEnumDeclaration(node: EnumDeclaration) {
            return isConst(node)
                ? declareSymbolAndAddToSymbolTable(node, SymbolFlags.ConstEnum, SymbolFlags.ConstEnumExcludes)
                : declareSymbolAndAddToSymbolTable(node, SymbolFlags.RegularEnum, SymbolFlags.RegularEnumExcludes);
        }

        function bindVariableDeclarationOrBindingElement(node: VariableDeclaration | BindingElement) {
            if (isBindingPattern(node.name)) {
                return SymbolFlags.None;
            }
            else if (isBlockOrCatchScoped(node)) {
                return bindBlockScopedVariableDeclaration(node);
            }
            else {
                return declareSymbolAndAddToSymbolTable(node, SymbolFlags.FunctionScopedVariable, SymbolFlags.FunctionScopedVariableExcludes);
            }
        }

        function bindParameter(node: ParameterDeclaration): SymbolFlags {
            if (isBindingPattern(node.name)) {
                bindAnonymousDeclaration(node, SymbolFlags.FunctionScopedVariable, getDestructuringParameterName(node));
            }
            else {
                declareSymbolAndAddToSymbolTable(node, SymbolFlags.FunctionScopedVariable, SymbolFlags.ParameterExcludes);
            }

            // If this is a property-parameter, then also declare the property symbol into the 
            // containing class.
            if (node.flags & NodeFlags.AccessibilityModifier &&
                node.parent.kind === SyntaxKind.Constructor &&
                (node.parent.parent.kind === SyntaxKind.ClassDeclaration || node.parent.parent.kind === SyntaxKind.ClassExpression)) {

                let classDeclaration = <ClassLikeDeclaration>node.parent.parent;
                declareSymbol(classDeclaration.symbol.members, classDeclaration.symbol, node, SymbolFlags.Property, SymbolFlags.PropertyExcludes);
            }

            return SymbolFlags.FunctionScopedVariable;
        }

        function bindPropertyOrMethodOrAccessor(node: Declaration, symbolFlags: SymbolFlags, symbolExcludes: SymbolFlags): SymbolFlags {
            return hasDynamicName(node)
                ? bindAnonymousDeclaration(node, symbolFlags, "__computed")
                : declareSymbolAndAddToSymbolTable(node, symbolFlags, symbolExcludes);
        }
    }
}