add related error span for default exports

src/compiler/binder.ts

@@ -403,13 +403,15 @@ namespace ts {
                             messageNeedsName = false;
                         }
 
-                        if (symbol.declarations && symbol.declarations.length) {
+                        let multipleDefaultExports = false;
+                        if (length(symbol.declarations)) {
                             // 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;
                                 messageNeedsName = false;
+                                multipleDefaultExports = true;
                             }
                             else {
                                 // This is to properly report an error in the case "export default { }" is after export default of class declaration or function declaration.
@@ -420,15 +422,26 @@ namespace ts {
                                     (node.kind === SyntaxKind.ExportAssignment && !(<ExportAssignment>node).isExportEquals)) {
                                     message = Diagnostics.A_module_cannot_have_multiple_default_exports;
                                     messageNeedsName = false;
+                                    multipleDefaultExports = true;
                                 }
                             }
                         }
 
-                        const addError = (decl: Declaration): void => {
-                            file.bindDiagnostics.push(createDiagnosticForNode(getNameOfDeclaration(decl) || decl, message, messageNeedsName ? getDisplayName(decl) : undefined));
-                        };
-                        forEach(symbol.declarations, addError);
-                        addError(node);
+                        const declarationName = getNameOfDeclaration(node) || node;
+                        const relatedInformation: DiagnosticRelatedInformation[] = [];
+                        forEach(symbol.declarations, (declaration, index) => {
+                            const decl = getNameOfDeclaration(declaration) || declaration;
+                            const diag = createDiagnosticForNode(decl, message, messageNeedsName ? getDisplayName(declaration) : undefined);
+                            file.bindDiagnostics.push(
+                                multipleDefaultExports ? addRelatedInfo(diag, createDiagnosticForNode(declarationName, index === 0 ? Diagnostics.Another_export_default_is_here : Diagnostics.and_here)) : diag
+                            );
+                            if (multipleDefaultExports) {
+                                relatedInformation.push(createDiagnosticForNode(decl, Diagnostics.The_first_export_default_is_here));
+                            }
+                        });
+
+                        const diag = createDiagnosticForNode(declarationName, message, messageNeedsName ? getDisplayName(node) : undefined);
+                        file.bindDiagnostics.push(multipleDefaultExports ? addRelatedInfo(diag, ...relatedInformation) : diag);
 
                         symbol = createSymbol(SymbolFlags.None, name);
                     }

src/compiler/checker.ts

@@ -792,14 +792,6 @@ namespace ts {
             }
         }
 
-        function addRelatedInfo(diagnostic: Diagnostic, ...relatedInformation: [DiagnosticRelatedInformation, ...DiagnosticRelatedInformation[]]) {
-            if (!diagnostic.relatedInformation) {
-                diagnostic.relatedInformation = [];
-            }
-            diagnostic.relatedInformation.push(...relatedInformation);
-            return diagnostic;
-        }
-
         function error(location: Node | undefined, message: DiagnosticMessage, arg0?: string | number, arg1?: string | number, arg2?: string | number, arg3?: string | number): Diagnostic {
             const diagnostic = location
                 ? createDiagnosticForNode(location, message, arg0, arg1, arg2, arg3)

src/compiler/diagnosticMessages.json

@@ -2593,6 +2593,14 @@
         "category": "Error",
         "code": 2751
     },
+    "The first export default is here.": {
+        "category": "Error",
+        "code": 2752
+    },
+    "Another export default is here.": {
+        "category": "Error",
+        "code": 2753
+    },
 
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",

src/compiler/utilities.ts

@@ -8516,6 +8516,14 @@ namespace ts {
         return arr.slice(index);
     }
 
+    export function addRelatedInfo<T extends Diagnostic>(diagnostic: T, ...relatedInformation: DiagnosticRelatedInformation[]): T {
+        if (!diagnostic.relatedInformation) {
+            diagnostic.relatedInformation = [];
+        }
+        diagnostic.relatedInformation.push(...relatedInformation);
+        return diagnostic;
+    }
+
     export function minAndMax<T>(arr: ReadonlyArray<T>, getValue: (value: T) => number): { readonly min: number, readonly max: number } {
         Debug.assert(arr.length !== 0);
         let min = getValue(arr[0]);

tests/baselines/reference/duplicateDefaultExport.errors.txt

@@ -6,7 +6,9 @@ tests/cases/compiler/duplicateDefaultExport.ts(2,1): error TS2528: A module cann
     export default 0;
     ~~~~~~~~~~~~~~~~~
 !!! error TS2528: A module cannot have multiple default exports.
+!!! related TS2752 tests/cases/compiler/duplicateDefaultExport.ts:2:1: The first export default is here.
     export default function() {}
     ~~~~~~
 !!! error TS2528: A module cannot have multiple default exports.
+!!! related TS2753 tests/cases/compiler/duplicateDefaultExport.ts:1:1: Another export default is here.
 

tests/baselines/reference/exportDefaultAlias_excludesEverything.errors.txt

@@ -6,8 +6,10 @@ tests/cases/compiler/exportDefaultAlias_excludesEverything.ts(3,16): error TS252
     export default interface A {}
                              ~
 !!! error TS2528: A module cannot have multiple default exports.
+!!! related TS2753 tests/cases/compiler/exportDefaultAlias_excludesEverything.ts:3:16: Another export default is here.
     interface B {}
     export default B;
                    ~
 !!! error TS2528: A module cannot have multiple default exports.
+!!! related TS2752 tests/cases/compiler/exportDefaultAlias_excludesEverything.ts:1:26: The first export default is here.
 

tests/baselines/reference/jsFileCompilationBindMultipleDefaultExports.errors.txt

@@ -9,12 +9,14 @@ tests/cases/compiler/a.js(3,20): error TS2652: Merged declaration 'a' cannot inc
     export default class a {
                          ~
 !!! error TS2528: A module cannot have multiple default exports.
+!!! related TS2753 tests/cases/compiler/a.js:3:15: Another export default is here.
                          ~
 !!! error TS2652: Merged declaration 'a' cannot include a default export declaration. Consider adding a separate 'export default a' declaration instead.
     }
     export default var a = 10;
 
 !!! error TS2528: A module cannot have multiple default exports.
+!!! related TS2752 tests/cases/compiler/a.js:1:22: The first export default is here.
                    ~~~
 !!! error TS1109: Expression expected.
                        ~

tests/baselines/reference/multipleDefaultExports01.errors.txt

@@ -1,25 +1,32 @@
 tests/cases/conformance/es6/modules/m1.ts(1,22): error TS2528: A module cannot have multiple default exports.
 tests/cases/conformance/es6/modules/m1.ts(5,25): error TS2528: A module cannot have multiple default exports.
+tests/cases/conformance/es6/modules/m1.ts(5,25): error TS2528: A module cannot have multiple default exports.
 tests/cases/conformance/es6/modules/m1.ts(10,16): error TS2528: A module cannot have multiple default exports.
 
 
-==== tests/cases/conformance/es6/modules/m1.ts (3 errors) ====
+==== tests/cases/conformance/es6/modules/m1.ts (4 errors) ====
     export default class foo {
                          ~~~
 !!! error TS2528: A module cannot have multiple default exports.
+!!! related TS2752 tests/cases/conformance/es6/modules/m1.ts:5:25: The first export default is here.
 
     }
 
     export default function bar() {
                             ~~~
 !!! error TS2528: A module cannot have multiple default exports.
+!!! related TS2753 tests/cases/conformance/es6/modules/m1.ts:1:22: Another export default is here.
+                            ~~~
+!!! error TS2528: A module cannot have multiple default exports.
+!!! related TS2753 tests/cases/conformance/es6/modules/m1.ts:10:16: Another export default is here.
 
     }
 
     var x = 10;
     export default x;
                    ~
 !!! error TS2528: A module cannot have multiple default exports.
+!!! related TS2752 tests/cases/conformance/es6/modules/m1.ts:5:25: The first export default is here.
 
 ==== tests/cases/conformance/es6/modules/m2.ts (0 errors) ====
     import Entity from "./m1"

tests/baselines/reference/multipleDefaultExports03.errors.txt

@@ -6,9 +6,11 @@ tests/cases/conformance/es6/modules/multipleDefaultExports03.ts(4,22): error TS2
     export default class C {
                          ~
 !!! error TS2528: A module cannot have multiple default exports.
+!!! related TS2753 tests/cases/conformance/es6/modules/multipleDefaultExports03.ts:4:22: Another export default is here.
     }
 
     export default class C {
                          ~
 !!! error TS2528: A module cannot have multiple default exports.
+!!! related TS2752 tests/cases/conformance/es6/modules/multipleDefaultExports03.ts:1:22: The first export default is here.
     }

tests/baselines/reference/multipleDefaultExports05.errors.txt

@@ -0,0 +1,25 @@
+tests/cases/conformance/es6/modules/multipleDefaultExports05.ts(1,22): error TS2528: A module cannot have multiple default exports.
+tests/cases/conformance/es6/modules/multipleDefaultExports05.ts(1,22): error TS2528: A module cannot have multiple default exports.
+tests/cases/conformance/es6/modules/multipleDefaultExports05.ts(3,22): error TS2528: A module cannot have multiple default exports.
+tests/cases/conformance/es6/modules/multipleDefaultExports05.ts(5,22): error TS2528: A module cannot have multiple default exports.
+
+
+==== tests/cases/conformance/es6/modules/multipleDefaultExports05.ts (4 errors) ====
+    export default class AA1 {}
+                         ~~~
+!!! error TS2528: A module cannot have multiple default exports.
+!!! related TS2753 tests/cases/conformance/es6/modules/multipleDefaultExports05.ts:3:22: Another export default is here.
+                         ~~~
+!!! error TS2528: A module cannot have multiple default exports.
+!!! related TS2753 tests/cases/conformance/es6/modules/multipleDefaultExports05.ts:5:22: Another export default is here.
+
+    export default class BB1 {}
+                         ~~~
+!!! error TS2528: A module cannot have multiple default exports.
+!!! related TS2752 tests/cases/conformance/es6/modules/multipleDefaultExports05.ts:1:22: The first export default is here.
+
+    export default class CC1 {}
+                         ~~~
+!!! error TS2528: A module cannot have multiple default exports.
+!!! related TS2752 tests/cases/conformance/es6/modules/multipleDefaultExports05.ts:1:22: The first export default is here.
+

tests/baselines/reference/multipleDefaultExports05.js

@@ -0,0 +1,29 @@
+//// [multipleDefaultExports05.ts]
+export default class AA1 {}
+
+export default class BB1 {}
+
+export default class CC1 {}
+
+
+//// [multipleDefaultExports05.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+var AA1 = /** @class */ (function () {
+    function AA1() {
+    }
+    return AA1;
+}());
+exports.default = AA1;
+var BB1 = /** @class */ (function () {
+    function BB1() {
+    }
+    return BB1;
+}());
+exports.default = BB1;
+var CC1 = /** @class */ (function () {
+    function CC1() {
+    }
+    return CC1;
+}());
+exports.default = CC1;

tests/baselines/reference/multipleDefaultExports05.symbols

@@ -0,0 +1,10 @@
+=== tests/cases/conformance/es6/modules/multipleDefaultExports05.ts ===
+export default class AA1 {}
+>AA1 : Symbol(AA1, Decl(multipleDefaultExports05.ts, 0, 0))
+
+export default class BB1 {}
+>BB1 : Symbol(BB1, Decl(multipleDefaultExports05.ts, 0, 27))
+
+export default class CC1 {}
+>CC1 : Symbol(CC1, Decl(multipleDefaultExports05.ts, 2, 27))
+

tests/baselines/reference/multipleDefaultExports05.types

@@ -0,0 +1,10 @@
+=== tests/cases/conformance/es6/modules/multipleDefaultExports05.ts ===
+export default class AA1 {}
+>AA1 : AA1
+
+export default class BB1 {}
+>BB1 : import("tests/cases/conformance/es6/modules/multipleDefaultExports05").default
+
+export default class CC1 {}
+>CC1 : import("tests/cases/conformance/es6/modules/multipleDefaultExports05").default
+

tests/baselines/reference/multipleExportDefault1.errors.txt

@@ -6,6 +6,7 @@ tests/cases/conformance/externalModules/multipleExportDefault1.ts(5,1): error TS
     export default function Foo (){
                             ~~~
 !!! error TS2528: A module cannot have multiple default exports.
+!!! related TS2753 tests/cases/conformance/externalModules/multipleExportDefault1.ts:5:1: Another export default is here.
 
     }
 
@@ -16,4 +17,5 @@ tests/cases/conformance/externalModules/multipleExportDefault1.ts(5,1): error TS
     };
     ~~
 !!! error TS2528: A module cannot have multiple default exports.
+!!! related TS2752 tests/cases/conformance/externalModules/multipleExportDefault1.ts:1:25: The first export default is here.
 

tests/baselines/reference/multipleExportDefault2.errors.txt

@@ -10,9 +10,11 @@ tests/cases/conformance/externalModules/multipleExportDefault2.ts(5,25): error T
     };
     ~~
 !!! error TS2528: A module cannot have multiple default exports.
+!!! related TS2752 tests/cases/conformance/externalModules/multipleExportDefault2.ts:5:25: The first export default is here.
 
     export default function Foo() { }
                             ~~~
 !!! error TS2528: A module cannot have multiple default exports.
+!!! related TS2753 tests/cases/conformance/externalModules/multipleExportDefault2.ts:1:1: Another export default is here.
 
 

tests/baselines/reference/multipleExportDefault3.errors.txt

@@ -10,9 +10,11 @@ tests/cases/conformance/externalModules/multipleExportDefault3.ts(5,22): error T
     };
     ~~
 !!! error TS2528: A module cannot have multiple default exports.
+!!! related TS2753 tests/cases/conformance/externalModules/multipleExportDefault3.ts:5:22: Another export default is here.
 
     export default class C { }
                          ~
 !!! error TS2528: A module cannot have multiple default exports.
+!!! related TS2752 tests/cases/conformance/externalModules/multipleExportDefault3.ts:1:1: The first export default is here.
 
 

tests/baselines/reference/multipleExportDefault4.errors.txt

@@ -6,11 +6,13 @@ tests/cases/conformance/externalModules/multipleExportDefault4.ts(3,1): error TS
     export default class C { }
                          ~
 !!! error TS2528: A module cannot have multiple default exports.
+!!! related TS2753 tests/cases/conformance/externalModules/multipleExportDefault4.ts:3:1: Another export default is here.
 
     export default {
     ~~~~~~~~~~~~~~~~
         uhoh: "another default",
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     };
     ~~
-!!! error TS2528: A module cannot have multiple default exports.
+!!! error TS2528: A module cannot have multiple default exports.
+!!! related TS2752 tests/cases/conformance/externalModules/multipleExportDefault4.ts:1:22: The first export default is here.

tests/baselines/reference/multipleExportDefault5.errors.txt

@@ -6,6 +6,8 @@ tests/cases/conformance/externalModules/multipleExportDefault5.ts(2,22): error T
     export default function bar() { }
                             ~~~
 !!! error TS2528: A module cannot have multiple default exports.
+!!! related TS2753 tests/cases/conformance/externalModules/multipleExportDefault5.ts:2:22: Another export default is here.
     export default class C {}
                          ~
-!!! error TS2528: A module cannot have multiple default exports.
+!!! error TS2528: A module cannot have multiple default exports.
+!!! related TS2752 tests/cases/conformance/externalModules/multipleExportDefault5.ts:1:25: The first export default is here.

tests/baselines/reference/multipleExportDefault6.errors.txt

@@ -10,11 +10,13 @@ tests/cases/conformance/externalModules/multipleExportDefault6.ts(5,1): error TS
     }
     ~
 !!! error TS2528: A module cannot have multiple default exports.
+!!! related TS2753 tests/cases/conformance/externalModules/multipleExportDefault6.ts:5:1: Another export default is here.
 
     export default {
     ~~~~~~~~~~~~~~~~
         lol: 2
     ~~~~~~~~~~
     }
     ~
-!!! error TS2528: A module cannot have multiple default exports.
+!!! error TS2528: A module cannot have multiple default exports.
+!!! related TS2752 tests/cases/conformance/externalModules/multipleExportDefault6.ts:1:1: The first export default is here.

tests/cases/conformance/es6/modules/multipleDefaultExports05.ts

@@ -0,0 +1,8 @@
+// @module: commonjs
+// @target: ES5
+
+export default class AA1 {}
+
+export default class BB1 {}
+
+export default class CC1 {}