Merge pull request #2339 from Microsoft/exportDefaultType

Support an optional type annotation on export default statement

src/compiler/binder.ts

@@ -505,7 +505,7 @@ module ts {
                     bindChildren(node, 0, /*isBlockScopeContainer*/ false);
                     break;
                 case SyntaxKind.ExportAssignment:
-                    if ((<ExportAssignment>node).expression.kind === SyntaxKind.Identifier) {
+                    if ((<ExportAssignment>node).expression && (<ExportAssignment>node).expression.kind === SyntaxKind.Identifier) {
                         // An export default clause with an identifier exports all meanings of that identifier
                         declareSymbol(container.symbol.exports, container.symbol, <Declaration>node, SymbolFlags.Alias, SymbolFlags.AliasExcludes);
                     }

src/compiler/checker.ts

@@ -567,7 +567,7 @@ module ts {
         }
 
         function getTargetOfExportAssignment(node: ExportAssignment): Symbol {
-            return resolveEntityName(<Identifier>node.expression, SymbolFlags.Value | SymbolFlags.Type | SymbolFlags.Namespace);
+            return node.expression && resolveEntityName(<Identifier>node.expression, SymbolFlags.Value | SymbolFlags.Type | SymbolFlags.Namespace);
         }
 
         function getTargetOfImportDeclaration(node: Declaration): Symbol {
@@ -623,7 +623,7 @@ module ts {
             if (!links.referenced) {
                 links.referenced = true;
                 let node = getDeclarationOfAliasSymbol(symbol);
-                if (node.kind === SyntaxKind.ExportAssignment) {
+                if (node.kind === SyntaxKind.ExportAssignment && (<ExportAssignment>node).expression) {
                     // export default <symbol>
                     checkExpressionCached((<ExportAssignment>node).expression);
                 }
@@ -2073,7 +2073,16 @@ module ts {
                 }
                 // Handle export default expressions
                 if (declaration.kind === SyntaxKind.ExportAssignment) {
-                    return links.type = checkExpression((<ExportAssignment>declaration).expression);
+                    var exportAssignment = <ExportAssignment>declaration;
+                    if (exportAssignment.expression) {
+                        return links.type = checkExpression(exportAssignment.expression);
+                    }
+                    else if (exportAssignment.type) {
+                        return links.type = getTypeFromTypeNode(exportAssignment.type);
+                    }
+                    else {
+                        return links.type = anyType;
+                    }
                 }
                 // Handle variable, parameter or property
                 links.type = resolvingType;
@@ -10075,12 +10084,21 @@ module ts {
             if (!checkGrammarModifiers(node) && (node.flags & NodeFlags.Modifier)) {
                 grammarErrorOnFirstToken(node, Diagnostics.An_export_assignment_cannot_have_modifiers);
             }
-            if (node.expression.kind === SyntaxKind.Identifier) {
-                markExportAsReferenced(node);
+            if (node.expression) {
+                if (node.expression.kind === SyntaxKind.Identifier) {
+                    markExportAsReferenced(node);
+                }
+                else {
+                    checkExpressionCached(node.expression);
+                }
             }
-            else {
-                checkExpressionCached(node.expression);
+            if (node.type) {
+                checkSourceElement(node.type);
+                if (!isInAmbientContext(node)) {
+                    grammarErrorOnFirstToken(node.type, Diagnostics.A_type_annotation_on_an_export_statement_is_only_allowed_in_an_ambient_external_module_declaration);
+                }
             }
+
             checkExternalModuleExports(container);
         }
 
@@ -10914,7 +10932,7 @@ module ts {
             }
 
             function generateNameForExportAssignment(node: ExportAssignment) {
-                if (node.expression.kind !== SyntaxKind.Identifier) {
+                if (node.expression && node.expression.kind !== SyntaxKind.Identifier) {
                     assignGeneratedName(node, makeUniqueName("default"));
                 }
             }

src/compiler/diagnosticInformationMap.generated.ts

@@ -158,6 +158,7 @@ module ts {
         An_extended_Unicode_escape_value_must_be_between_0x0_and_0x10FFFF_inclusive: { code: 1198, category: DiagnosticCategory.Error, key: "An extended Unicode escape value must be between 0x0 and 0x10FFFF inclusive." },
         Unterminated_Unicode_escape_sequence: { code: 1199, category: DiagnosticCategory.Error, key: "Unterminated Unicode escape sequence." },
         Line_terminator_not_permitted_before_arrow: { code: 1200, category: DiagnosticCategory.Error, key: "Line terminator not permitted before arrow." },
+        A_type_annotation_on_an_export_statement_is_only_allowed_in_an_ambient_external_module_declaration: { code: 1201, category: DiagnosticCategory.Error, key: "A type annotation on an export statement is only allowed in an ambient external module declaration." },
         Duplicate_identifier_0: { code: 2300, category: DiagnosticCategory.Error, key: "Duplicate identifier '{0}'." },
         Initializer_of_instance_member_variable_0_cannot_reference_identifier_1_declared_in_the_constructor: { code: 2301, category: DiagnosticCategory.Error, key: "Initializer of instance member variable '{0}' cannot reference identifier '{1}' declared in the constructor." },
         Static_members_cannot_reference_class_type_parameters: { code: 2302, category: DiagnosticCategory.Error, key: "Static members cannot reference class type parameters." },

src/compiler/diagnosticMessages.json

@@ -617,12 +617,17 @@
     },
     "Unterminated Unicode escape sequence.": {
         "category": "Error",
-        "code":  1199
+        "code": 1199
     },
     "Line terminator not permitted before arrow.": {
         "category": "Error",
         "code": 1200
     },
+    "A type annotation on an export statement is only allowed in an ambient external module declaration.": {
+        "category": "Error",
+        "code": 1201
+    },
+
     "Duplicate identifier '{0}'.": {
         "category": "Error",
         "code": 2300

src/compiler/parser.ts

@@ -283,7 +283,8 @@ module ts {
                     visitNode(cbNode, (<ImportOrExportSpecifier>node).name);
             case SyntaxKind.ExportAssignment:
                 return visitNodes(cbNodes, node.modifiers) ||
-                    visitNode(cbNode, (<ExportAssignment>node).expression);
+                    visitNode(cbNode, (<ExportAssignment>node).expression) ||
+                    visitNode(cbNode, (<ExportAssignment>node).type);
             case SyntaxKind.TemplateExpression:
                 return visitNode(cbNode, (<TemplateExpression>node).head) || visitNodes(cbNodes, (<TemplateExpression>node).templateSpans);
             case SyntaxKind.TemplateSpan:
@@ -4867,12 +4868,17 @@ module ts {
             setModifiers(node, modifiers);
             if (parseOptional(SyntaxKind.EqualsToken)) {
                 node.isExportEquals = true;
+                node.expression = parseAssignmentExpressionOrHigher();
             }
             else {
                 parseExpected(SyntaxKind.DefaultKeyword);
+                if (parseOptional(SyntaxKind.ColonToken)) {
+                    node.type = parseType();
+                }
+                else {
+                    node.expression = parseAssignmentExpressionOrHigher();
+                }
             }
-            //node.exportName = parseIdentifier();
-            node.expression = parseAssignmentExpressionOrHigher();
             parseSemicolon();
             return finishNode(node);
         }

src/compiler/types.ts

@@ -944,7 +944,8 @@ module ts {
 
     export interface ExportAssignment extends Declaration, ModuleElement {
         isExportEquals?: boolean;
-        expression: Expression;
+        expression?: Expression;
+        type?: TypeNode;
     }
 
     export interface FileReference extends TextRange {

src/services/breakpoints.ts

@@ -173,6 +173,10 @@ module ts.BreakpointResolver {
                         return textSpan(node, (<ThrowStatement>node).expression);
 
                     case SyntaxKind.ExportAssignment:
+                        if (!(<ExportAssignment>node).expression) {
+                            return undefined;
+                        }
+
                         // span on export = id
                         return textSpan(node, (<ExportAssignment>node).expression);
 

tests/baselines/reference/APISample_compile.js

@@ -765,7 +765,8 @@ declare module "typescript" {
     type ExportSpecifier = ImportOrExportSpecifier;
     interface ExportAssignment extends Declaration, ModuleElement {
         isExportEquals?: boolean;
-        expression: Expression;
+        expression?: Expression;
+        type?: TypeNode;
     }
     interface FileReference extends TextRange {
         fileName: string;

tests/baselines/reference/APISample_compile.types

@@ -2333,9 +2333,13 @@ declare module "typescript" {
         isExportEquals?: boolean;
 >isExportEquals : boolean
 
-        expression: Expression;
+        expression?: Expression;
 >expression : Expression
 >Expression : Expression
+
+        type?: TypeNode;
+>type : TypeNode
+>TypeNode : TypeNode
     }
     interface FileReference extends TextRange {
 >FileReference : FileReference

tests/baselines/reference/APISample_linter.js

@@ -796,7 +796,8 @@ declare module "typescript" {
     type ExportSpecifier = ImportOrExportSpecifier;
     interface ExportAssignment extends Declaration, ModuleElement {
         isExportEquals?: boolean;
-        expression: Expression;
+        expression?: Expression;
+        type?: TypeNode;
     }
     interface FileReference extends TextRange {
         fileName: string;

tests/baselines/reference/APISample_linter.types

@@ -2479,9 +2479,13 @@ declare module "typescript" {
         isExportEquals?: boolean;
 >isExportEquals : boolean
 
-        expression: Expression;
+        expression?: Expression;
 >expression : Expression
 >Expression : Expression
+
+        type?: TypeNode;
+>type : TypeNode
+>TypeNode : TypeNode
     }
     interface FileReference extends TextRange {
 >FileReference : FileReference

tests/baselines/reference/APISample_transform.js

@@ -797,7 +797,8 @@ declare module "typescript" {
     type ExportSpecifier = ImportOrExportSpecifier;
     interface ExportAssignment extends Declaration, ModuleElement {
         isExportEquals?: boolean;
-        expression: Expression;
+        expression?: Expression;
+        type?: TypeNode;
     }
     interface FileReference extends TextRange {
         fileName: string;

tests/baselines/reference/APISample_transform.types

@@ -2429,9 +2429,13 @@ declare module "typescript" {
         isExportEquals?: boolean;
 >isExportEquals : boolean
 
-        expression: Expression;
+        expression?: Expression;
 >expression : Expression
 >Expression : Expression
+
+        type?: TypeNode;
+>type : TypeNode
+>TypeNode : TypeNode
     }
     interface FileReference extends TextRange {
 >FileReference : FileReference

tests/baselines/reference/APISample_watcher.js

@@ -834,7 +834,8 @@ declare module "typescript" {
     type ExportSpecifier = ImportOrExportSpecifier;
     interface ExportAssignment extends Declaration, ModuleElement {
         isExportEquals?: boolean;
-        expression: Expression;
+        expression?: Expression;
+        type?: TypeNode;
     }
     interface FileReference extends TextRange {
         fileName: string;

tests/baselines/reference/APISample_watcher.types

@@ -2602,9 +2602,13 @@ declare module "typescript" {
         isExportEquals?: boolean;
 >isExportEquals : boolean
 
-        expression: Expression;
+        expression?: Expression;
 >expression : Expression
 >Expression : Expression
+
+        type?: TypeNode;
+>type : TypeNode
+>TypeNode : TypeNode
     }
     interface FileReference extends TextRange {
 >FileReference : FileReference

tests/baselines/reference/exportDefaultTypeAnnoation.errors.txt

@@ -0,0 +1,8 @@
+tests/cases/compiler/exportDefaultTypeAnnoation.ts(2,18): error TS1201: A type annotation on an export statement is only allowed in an ambient external module declaration.
+
+
+==== tests/cases/compiler/exportDefaultTypeAnnoation.ts (1 errors) ====
+    
+    export default : number;
+                     ~~~~~~
+!!! error TS1201: A type annotation on an export statement is only allowed in an ambient external module declaration.

tests/baselines/reference/exportDefaultTypeAnnoation.js

@@ -0,0 +1,6 @@
+//// [exportDefaultTypeAnnoation.ts]
+
+export default : number;
+
+//// [exportDefaultTypeAnnoation.js]
+module.exports = ;

tests/baselines/reference/exportDefaultTypeAnnoation2.js

@@ -0,0 +1,7 @@
+//// [exportDefaultTypeAnnoation2.ts]
+
+declare module "mod" {
+    export default : number;
+}
+
+//// [exportDefaultTypeAnnoation2.js]

tests/baselines/reference/exportDefaultTypeAnnoation2.types

@@ -0,0 +1,6 @@
+=== tests/cases/compiler/exportDefaultTypeAnnoation2.ts ===
+
+No type information for this code.declare module "mod" {
+No type information for this code.    export default : number;
+No type information for this code.}
+No type information for this code.

tests/baselines/reference/exportDefaultTypeAnnoation3.errors.txt

@@ -0,0 +1,21 @@
+tests/cases/compiler/reference1.ts(2,5): error TS2322: Type 'number' is not assignable to type 'string'.
+tests/cases/compiler/reference2.ts(2,5): error TS2322: Type 'number' is not assignable to type 'string'.
+
+
+==== tests/cases/compiler/mod.d.ts (0 errors) ====
+    
+    declare module "mod" {
+        export default : number;
+    }
+    
+==== tests/cases/compiler/reference1.ts (1 errors) ====
+    import d from "mod";
+    var s: string = d; // Error
+        ~
+!!! error TS2322: Type 'number' is not assignable to type 'string'.
+    
+==== tests/cases/compiler/reference2.ts (1 errors) ====
+    import { default as d } from "mod";
+    var s: string = d; // Error
+        ~
+!!! error TS2322: Type 'number' is not assignable to type 'string'.

tests/baselines/reference/exportDefaultTypeAnnoation3.js

@@ -0,0 +1,22 @@
+//// [tests/cases/compiler/exportDefaultTypeAnnoation3.ts] ////
+
+//// [mod.d.ts]
+
+declare module "mod" {
+    export default : number;
+}
+
+//// [reference1.ts]
+import d from "mod";
+var s: string = d; // Error
+
+//// [reference2.ts]
+import { default as d } from "mod";
+var s: string = d; // Error
+
+//// [reference1.js]
+var d = require("mod");
+var s = d; // Error
+//// [reference2.js]
+var _mod = require("mod");
+var s = _mod.default; // Error

tests/cases/compiler/exportDefaultTypeAnnoation.ts

@@ -0,0 +1,4 @@
+// @target: es5
+// @module: commonjs
+
+export default : number;

tests/cases/compiler/exportDefaultTypeAnnoation2.ts

@@ -0,0 +1,6 @@
+// @target: es5
+// @module: commonjs
+
+declare module "mod" {
+    export default : number;
+}

tests/cases/compiler/exportDefaultTypeAnnoation3.ts

@@ -0,0 +1,15 @@
+// @target: es5
+// @module: commonjs
+
+// @fileName: mod.d.ts
+declare module "mod" {
+    export default : number;
+}
+
+// @fileName: reference1.ts
+import d from "mod";
+var s: string = d; // Error
+
+// @fileName: reference2.ts
+import { default as d } from "mod";
+var s: string = d; // Error