Merge pull request #10239 from Microsoft/fix10193

Fix 10193: Compiler crash with decorator and two "export default"s

src/compiler/binder.ts

@@ -355,11 +355,24 @@ namespace ts {
                             ? Diagnostics.Cannot_redeclare_block_scoped_variable_0
                             : Diagnostics.Duplicate_identifier_0;
 
-                        forEach(symbol.declarations, declaration => {
-                            if (hasModifier(declaration, ModifierFlags.Default)) {
+                        if (symbol.declarations && symbol.declarations.length) {
+                            // If the current node is a default export of some sort, then check if
+                            // there are any other default exports that we need to error on.
+                            // We'll know whether we have other default exports depending on if `symbol` already has a declaration list set.
+                            if (isDefaultExport) {
                                 message = Diagnostics.A_module_cannot_have_multiple_default_exports;
                             }
-                        });
+                            else {
+                                // This is to properly report an error in the case "export default { }" is after export default of class declaration or function declaration.
+                                // Error on multiple export default in the following case:
+                                // 1. multiple export default of class declaration or function declaration by checking NodeFlags.Default
+                                // 2. multiple export default of export assignment. This one doesn't have NodeFlags.Default on (as export default doesn't considered as modifiers)
+                                if (symbol.declarations && symbol.declarations.length &&
+                                    (isDefaultExport || (node.kind === SyntaxKind.ExportAssignment &&  !(<ExportAssignment>node).isExportEquals))) {
+                                        message = Diagnostics.A_module_cannot_have_multiple_default_exports;
+                                 }
+                            }
+                        }
 
                         forEach(symbol.declarations, declaration => {
                             file.bindDiagnostics.push(createDiagnosticForNode(declaration.name || declaration, message, getDisplayName(declaration)));
@@ -1944,12 +1957,15 @@ namespace ts {
                 bindAnonymousDeclaration(node, SymbolFlags.Alias, getDeclarationName(node));
             }
             else {
+                // An export default clause with an expression exports a value
+                // We want to exclude both class and function here,  this is necessary to issue an error when there are both
+                // default export-assignment and default export function and class declaration.
                 const flags = node.kind === SyntaxKind.ExportAssignment && exportAssignmentIsAlias(<ExportAssignment>node)
                     // An export default clause with an EntityNameExpression exports all meanings of that identifier
                     ? SymbolFlags.Alias
                     // An export default clause with any other expression exports a value
                     : SymbolFlags.Property;
-                declareSymbol(container.symbol.exports, container.symbol, node, flags, SymbolFlags.PropertyExcludes | SymbolFlags.AliasExcludes);
+                declareSymbol(container.symbol.exports, container.symbol, node, flags, SymbolFlags.Property | SymbolFlags.AliasExcludes | SymbolFlags.Class | SymbolFlags.Function);
             }
         }
 

tests/baselines/reference/jsFileCompilationBindMultipleDefaultExports.errors.txt

@@ -1,9 +1,15 @@
+tests/cases/compiler/a.js(1,22): error TS2528: A module cannot have multiple default exports.
+tests/cases/compiler/a.js(3,1): error TS2528: A module cannot have multiple default exports.
 tests/cases/compiler/a.js(3,16): error TS1109: Expression expected.
 
 
-==== tests/cases/compiler/a.js (1 errors) ====
+==== tests/cases/compiler/a.js (3 errors) ====
     export default class a {
+                         ~
+!!! error TS2528: A module cannot have multiple default exports.
     }
     export default var a = 10;
+    ~~~~~~~~~~~~~~
+!!! error TS2528: A module cannot have multiple default exports.
                    ~~~
 !!! error TS1109: Expression expected.

tests/baselines/reference/multipleDefaultExports01.errors.txt

@@ -1,16 +1,13 @@
-tests/cases/conformance/es6/modules/m1.ts(2,22): error TS2323: Cannot redeclare exported variable 'default'.
 tests/cases/conformance/es6/modules/m1.ts(2,22): error TS2528: A module cannot have multiple default exports.
 tests/cases/conformance/es6/modules/m1.ts(6,25): error TS2528: A module cannot have multiple default exports.
-tests/cases/conformance/es6/modules/m1.ts(11,1): error TS2323: Cannot redeclare exported variable 'default'.
+tests/cases/conformance/es6/modules/m1.ts(11,1): error TS2528: A module cannot have multiple default exports.
 tests/cases/conformance/es6/modules/m2.ts(3,1): error TS2348: Value of type 'typeof foo' is not callable. Did you mean to include 'new'?
 
 
-==== tests/cases/conformance/es6/modules/m1.ts (4 errors) ====
+==== tests/cases/conformance/es6/modules/m1.ts (3 errors) ====
     
     export default class foo {
                          ~~~
-!!! error TS2323: Cannot redeclare exported variable 'default'.
-                         ~~~
 !!! error TS2528: A module cannot have multiple default exports.
     
     }
@@ -24,7 +21,7 @@ tests/cases/conformance/es6/modules/m2.ts(3,1): error TS2348: Value of type 'typ
     var x = 10;
     export default x;
     ~~~~~~~~~~~~~~~~~
-!!! error TS2323: Cannot redeclare exported variable 'default'.
+!!! error TS2528: A module cannot have multiple default exports.
     
 ==== tests/cases/conformance/es6/modules/m2.ts (1 errors) ====
     import Entity from "./m1"

tests/baselines/reference/multipleExportDefault1.errors.txt

@@ -0,0 +1,19 @@
+tests/cases/conformance/externalModules/multipleExportDefault1.ts(1,25): error TS2528: A module cannot have multiple default exports.
+tests/cases/conformance/externalModules/multipleExportDefault1.ts(5,1): error TS2528: A module cannot have multiple default exports.
+
+
+==== tests/cases/conformance/externalModules/multipleExportDefault1.ts (2 errors) ====
+    export default function Foo (){
+                            ~~~
+!!! error TS2528: A module cannot have multiple default exports.
+        
+    }
+    
+    export default {
+    ~~~~~~~~~~~~~~~~
+        uhoh: "another default",
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+    };
+    ~~
+!!! error TS2528: A module cannot have multiple default exports.
+    

tests/baselines/reference/multipleExportDefault1.js

@@ -0,0 +1,20 @@
+//// [multipleExportDefault1.ts]
+export default function Foo (){
+    
+}
+
+export default {
+    uhoh: "another default",
+};
+
+
+//// [multipleExportDefault1.js]
+"use strict";
+function Foo() {
+}
+exports.__esModule = true;
+exports["default"] = Foo;
+exports.__esModule = true;
+exports["default"] = {
+    uhoh: "another default"
+};

tests/baselines/reference/multipleExportDefault2.errors.txt

@@ -0,0 +1,18 @@
+tests/cases/conformance/externalModules/multipleExportDefault2.ts(1,1): error TS2528: A module cannot have multiple default exports.
+tests/cases/conformance/externalModules/multipleExportDefault2.ts(5,25): error TS2528: A module cannot have multiple default exports.
+
+
+==== tests/cases/conformance/externalModules/multipleExportDefault2.ts (2 errors) ====
+    export default {
+    ~~~~~~~~~~~~~~~~
+        uhoh: "another default",
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+    };
+    ~~
+!!! error TS2528: A module cannot have multiple default exports.
+    
+    export default function Foo() { }
+                            ~~~
+!!! error TS2528: A module cannot have multiple default exports.
+    
+    

tests/baselines/reference/multipleExportDefault2.js

@@ -0,0 +1,18 @@
+//// [multipleExportDefault2.ts]
+export default {
+    uhoh: "another default",
+};
+
+export default function Foo() { }
+
+
+
+//// [multipleExportDefault2.js]
+"use strict";
+exports.__esModule = true;
+exports["default"] = {
+    uhoh: "another default"
+};
+function Foo() { }
+exports.__esModule = true;
+exports["default"] = Foo;

tests/baselines/reference/multipleExportDefault3.errors.txt

@@ -0,0 +1,18 @@
+tests/cases/conformance/externalModules/multipleExportDefault3.ts(1,1): error TS2528: A module cannot have multiple default exports.
+tests/cases/conformance/externalModules/multipleExportDefault3.ts(5,22): error TS2528: A module cannot have multiple default exports.
+
+
+==== tests/cases/conformance/externalModules/multipleExportDefault3.ts (2 errors) ====
+    export default {
+    ~~~~~~~~~~~~~~~~
+        uhoh: "another default",
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+    };
+    ~~
+!!! error TS2528: A module cannot have multiple default exports.
+    
+    export default class C { }
+                         ~
+!!! error TS2528: A module cannot have multiple default exports.
+    
+    

tests/baselines/reference/multipleExportDefault3.js

@@ -0,0 +1,22 @@
+//// [multipleExportDefault3.ts]
+export default {
+    uhoh: "another default",
+};
+
+export default class C { }
+
+
+
+//// [multipleExportDefault3.js]
+"use strict";
+exports.__esModule = true;
+exports["default"] = {
+    uhoh: "another default"
+};
+var C = (function () {
+    function C() {
+    }
+    return C;
+}());
+exports.__esModule = true;
+exports["default"] = C;

tests/baselines/reference/multipleExportDefault4.errors.txt

@@ -0,0 +1,16 @@
+tests/cases/conformance/externalModules/multipleExportDefault4.ts(1,22): error TS2528: A module cannot have multiple default exports.
+tests/cases/conformance/externalModules/multipleExportDefault4.ts(3,1): error TS2528: A module cannot have multiple default exports.
+
+
+==== tests/cases/conformance/externalModules/multipleExportDefault4.ts (2 errors) ====
+    export default class C { }
+                         ~
+!!! error TS2528: A module cannot have multiple default exports.
+    
+    export default {
+    ~~~~~~~~~~~~~~~~
+        uhoh: "another default",
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+    };
+    ~~
+!!! error TS2528: A module cannot have multiple default exports.

tests/baselines/reference/multipleExportDefault4.js

@@ -0,0 +1,20 @@
+//// [multipleExportDefault4.ts]
+export default class C { }
+
+export default {
+    uhoh: "another default",
+};
+
+//// [multipleExportDefault4.js]
+"use strict";
+var C = (function () {
+    function C() {
+    }
+    return C;
+}());
+exports.__esModule = true;
+exports["default"] = C;
+exports.__esModule = true;
+exports["default"] = {
+    uhoh: "another default"
+};

tests/baselines/reference/multipleExportDefault5.errors.txt

@@ -0,0 +1,11 @@
+tests/cases/conformance/externalModules/multipleExportDefault5.ts(1,25): error TS2528: A module cannot have multiple default exports.
+tests/cases/conformance/externalModules/multipleExportDefault5.ts(2,22): error TS2528: A module cannot have multiple default exports.
+
+
+==== tests/cases/conformance/externalModules/multipleExportDefault5.ts (2 errors) ====
+    export default function bar() { }
+                            ~~~
+!!! error TS2528: A module cannot have multiple default exports.
+    export default class C {}
+                         ~
+!!! error TS2528: A module cannot have multiple default exports.

tests/baselines/reference/multipleExportDefault5.js

@@ -0,0 +1,16 @@
+//// [multipleExportDefault5.ts]
+export default function bar() { }
+export default class C {}
+
+//// [multipleExportDefault5.js]
+"use strict";
+function bar() { }
+exports.__esModule = true;
+exports["default"] = bar;
+var C = (function () {
+    function C() {
+    }
+    return C;
+}());
+exports.__esModule = true;
+exports["default"] = C;

tests/baselines/reference/multipleExportDefault6.errors.txt

@@ -0,0 +1,20 @@
+tests/cases/conformance/externalModules/multipleExportDefault6.ts(1,1): error TS2528: A module cannot have multiple default exports.
+tests/cases/conformance/externalModules/multipleExportDefault6.ts(5,1): error TS2528: A module cannot have multiple default exports.
+
+
+==== tests/cases/conformance/externalModules/multipleExportDefault6.ts (2 errors) ====
+    export default {
+    ~~~~~~~~~~~~~~~~
+        lol: 1
+    ~~~~~~~~~~
+    }
+    ~
+!!! error TS2528: A module cannot have multiple default exports.
+    
+    export default {
+    ~~~~~~~~~~~~~~~~
+        lol: 2
+    ~~~~~~~~~~
+    }
+    ~
+!!! error TS2528: A module cannot have multiple default exports.

tests/baselines/reference/multipleExportDefault6.js

@@ -0,0 +1,19 @@
+//// [multipleExportDefault6.ts]
+export default {
+    lol: 1
+}
+
+export default {
+    lol: 2
+}
+
+//// [multipleExportDefault6.js]
+"use strict";
+exports.__esModule = true;
+exports["default"] = {
+    lol: 1
+};
+exports.__esModule = true;
+exports["default"] = {
+    lol: 2
+};

tests/cases/conformance/externalModules/multipleExportDefault1.ts

@@ -0,0 +1,7 @@
+export default function Foo (){
+    
+}
+
+export default {
+    uhoh: "another default",
+};

tests/cases/conformance/externalModules/multipleExportDefault2.ts

@@ -0,0 +1,6 @@
+export default {
+    uhoh: "another default",
+};
+
+export default function Foo() { }
+

tests/cases/conformance/externalModules/multipleExportDefault3.ts

@@ -0,0 +1,6 @@
+export default {
+    uhoh: "another default",
+};
+
+export default class C { }
+

tests/cases/conformance/externalModules/multipleExportDefault4.ts

@@ -0,0 +1,5 @@
+export default class C { }
+
+export default {
+    uhoh: "another default",
+};

tests/cases/conformance/externalModules/multipleExportDefault5.ts

@@ -0,0 +1,2 @@
+export default function bar() { }
+export default class C {}

tests/cases/conformance/externalModules/multipleExportDefault6.ts

@@ -0,0 +1,7 @@
+export default {
+    lol: 1
+}
+
+export default {
+    lol: 2
+}