Link back to likely declarations in "did you mean...?" error messages

src/compiler/checker.ts

@@ -295,7 +295,7 @@ namespace ts {
             getAllPossiblePropertiesOfTypes,
             getSuggestionForNonexistentProperty: (node, type) => getSuggestionForNonexistentProperty(node, type),
             getSuggestionForNonexistentSymbol: (location, name, meaning) => getSuggestionForNonexistentSymbol(location, escapeLeadingUnderscores(name), meaning),
-            getSuggestionForNonexistentModule: (node, target) => getSuggestionForNonexistentModule(node, target),
+            getSuggestionForNonexistentExport: (node, target) => getSuggestionForNonexistentExport(node, target),
             getBaseConstraintOfType,
             getDefaultFromTypeParameter: type => type && type.flags & TypeFlags.TypeParameter ? getDefaultFromTypeParameter(type as TypeParameter) : undefined,
             resolveName(name, location, meaning, excludeGlobals) {
@@ -710,7 +710,7 @@ namespace ts {
             }
         }
 
-        function addRelatedInfo(diagnostic: Diagnostic, ...relatedInformation: DiagnosticRelatedInformation[]) {
+        function addRelatedInfo(diagnostic: Diagnostic, ...relatedInformation: [DiagnosticRelatedInformation, ...DiagnosticRelatedInformation[]]) {
             if (!diagnostic.relatedInformation) {
                 diagnostic.relatedInformation = [];
             }
@@ -1434,11 +1434,18 @@ namespace ts {
                         !checkAndReportErrorForUsingTypeAsNamespace(errorLocation, name, meaning) &&
                         !checkAndReportErrorForUsingTypeAsValue(errorLocation, name, meaning) &&
                         !checkAndReportErrorForUsingNamespaceModuleAsValue(errorLocation, name, meaning)) {
-                        let suggestion: string | undefined;
+                        let suggestion: Symbol | undefined;
                         if (suggestedNameNotFoundMessage && suggestionCount < maximumSuggestionCount) {
-                            suggestion = getSuggestionForNonexistentSymbol(originalLocation, name, meaning);
+                            suggestion = getSuggestedSymbolForNonexistentSymbol(originalLocation, name, meaning);
                             if (suggestion) {
-                                error(errorLocation, suggestedNameNotFoundMessage, diagnosticName(nameArg!), suggestion);
+                                const suggestionName = symbolToString(suggestion);
+                                const diagnostic = error(errorLocation, suggestedNameNotFoundMessage, diagnosticName(nameArg!), suggestionName);
+                                if (suggestion.valueDeclaration) {
+                                    addRelatedInfo(
+                                        diagnostic,
+                                        createDiagnosticForNode(suggestion.valueDeclaration, Diagnostics._0_is_declared_here, suggestionName)
+                                    );
+                                }
                             }
                         }
                         if (!suggestion) {
@@ -1674,7 +1681,7 @@ namespace ts {
 
                 if (diagnosticMessage) {
                     addRelatedInfo(diagnosticMessage,
-                        createDiagnosticForNode(declaration, Diagnostics._0_was_declared_here, declarationName)
+                        createDiagnosticForNode(declaration, Diagnostics._0_is_declared_here, declarationName)
                     );
                 }
             }
@@ -1866,9 +1873,15 @@ namespace ts {
                     if (!symbol) {
                         const moduleName = getFullyQualifiedName(moduleSymbol);
                         const declarationName = declarationNameToString(name);
-                        const suggestion = getSuggestionForNonexistentModule(name, targetSymbol);
+                        const suggestion = getSuggestedSymbolForNonexistentModule(name, targetSymbol);
                         if (suggestion !== undefined) {
-                            error(name, Diagnostics.Module_0_has_no_exported_member_1_Did_you_mean_2, moduleName, declarationName, suggestion);
+                            const suggestionName = symbolToString(suggestion);
+                            const diagnostic = error(name, Diagnostics.Module_0_has_no_exported_member_1_Did_you_mean_2, moduleName, declarationName, suggestionName);
+                            if (suggestion.valueDeclaration) {
+                                addRelatedInfo(diagnostic,
+                                    createDiagnosticForNode(suggestion.valueDeclaration, Diagnostics._0_is_declared_here, suggestionName)
+                                );
+                            }
                         }
                         else {
                             error(name, Diagnostics.Module_0_has_no_exported_member_1, moduleName, declarationName);
@@ -17661,7 +17674,7 @@ namespace ts {
 
             if (diagnosticMessage) {
                 addRelatedInfo(diagnosticMessage,
-                    createDiagnosticForNode(valueDeclaration, Diagnostics._0_was_declared_here, declarationName)
+                    createDiagnosticForNode(valueDeclaration, Diagnostics._0_is_declared_here, declarationName)
                 );
             }
         }
@@ -17711,6 +17724,7 @@ namespace ts {
 
         function reportNonexistentProperty(propNode: Identifier, containingType: Type) {
             let errorInfo: DiagnosticMessageChain | undefined;
+            let relatedInfo: Diagnostic | undefined;
             if (containingType.flags & TypeFlags.Union && !(containingType.flags & TypeFlags.Primitive)) {
                 for (const subtype of (containingType as UnionType).types) {
                     if (!getPropertyOfType(subtype, propNode.escapedText)) {
@@ -17724,30 +17738,34 @@ namespace ts {
                 errorInfo = chainDiagnosticMessages(errorInfo, Diagnostics.Property_0_does_not_exist_on_type_1_Did_you_forget_to_use_await, declarationNameToString(propNode), typeToString(containingType));
             }
             else {
-                const suggestion = getSuggestionForNonexistentProperty(propNode, containingType);
+                const suggestion = getSuggestedSymbolForNonexistentProperty(propNode, containingType);
                 if (suggestion !== undefined) {
-                    errorInfo = chainDiagnosticMessages(errorInfo, Diagnostics.Property_0_does_not_exist_on_type_1_Did_you_mean_2, declarationNameToString(propNode), typeToString(containingType), suggestion);
+                    const suggestedName = symbolName(suggestion);
+                    errorInfo = chainDiagnosticMessages(errorInfo, Diagnostics.Property_0_does_not_exist_on_type_1_Did_you_mean_2, declarationNameToString(propNode), typeToString(containingType), suggestedName);
+                    relatedInfo = suggestion.valueDeclaration && createDiagnosticForNode(suggestion.valueDeclaration, Diagnostics._0_is_declared_here, suggestedName);
                 }
                 else {
-                    const suggestion = getSuggestionForNonexistentProperty(propNode, containingType);
-                    if (suggestion !== undefined) {
-                        errorInfo = chainDiagnosticMessages(errorInfo, Diagnostics.Property_0_does_not_exist_on_type_1_Did_you_mean_2, declarationNameToString(propNode), typeToString(containingType), suggestion);
-                    }
-                    else {
-                        errorInfo = chainDiagnosticMessages(errorInfo, Diagnostics.Property_0_does_not_exist_on_type_1, declarationNameToString(propNode), typeToString(containingType));
-                    }
+                    errorInfo = chainDiagnosticMessages(errorInfo, Diagnostics.Property_0_does_not_exist_on_type_1, declarationNameToString(propNode), typeToString(containingType));
                 }
             }
 
-            diagnostics.add(createDiagnosticForNodeFromMessageChain(propNode, errorInfo));
+            const resultDiagnostic = createDiagnosticForNodeFromMessageChain(propNode, errorInfo);
+            if (relatedInfo) {
+                addRelatedInfo(resultDiagnostic, relatedInfo);
+            }
+            diagnostics.add(resultDiagnostic);
+        }
+
+        function getSuggestedSymbolForNonexistentProperty(name: Identifier | string, containingType: Type): Symbol | undefined {
+            return getSpellingSuggestionForName(isString(name) ? name : idText(name), getPropertiesOfType(containingType), SymbolFlags.Value);
         }
 
         function getSuggestionForNonexistentProperty(name: Identifier | string, containingType: Type): string | undefined {
-            const suggestion = getSpellingSuggestionForName(isString(name) ? name : idText(name), getPropertiesOfType(containingType), SymbolFlags.Value);
+            const suggestion = getSuggestedSymbolForNonexistentProperty(name, containingType);
             return suggestion && symbolName(suggestion);
         }
 
-        function getSuggestionForNonexistentSymbol(location: Node | undefined, outerName: __String, meaning: SymbolFlags): string | undefined {
+        function getSuggestedSymbolForNonexistentSymbol(location: Node | undefined, outerName: __String, meaning: SymbolFlags): Symbol | undefined {
             Debug.assert(outerName !== undefined, "outername should always be defined");
             const result = resolveNameHelper(location, outerName, meaning, /*nameNotFoundMessage*/ undefined, outerName, /*isUse*/ false, /*excludeGlobals*/ false, (symbols, name, meaning) => {
                 Debug.assertEqual(outerName, name, "name should equal outerName");
@@ -17757,11 +17775,20 @@ namespace ts {
                 // However, resolveNameHelper will continue and call this callback again, so we'll eventually get a correct suggestion.
                 return symbol || getSpellingSuggestionForName(unescapeLeadingUnderscores(name), arrayFrom(symbols.values()), meaning);
             });
-            return result && symbolName(result);
+            return result;
+        }
+
+        function getSuggestionForNonexistentSymbol(location: Node | undefined, outerName: __String, meaning: SymbolFlags): string | undefined {
+            const symbolResult = getSuggestedSymbolForNonexistentSymbol(location, outerName, meaning);
+            return symbolResult && symbolName(symbolResult);
+        }
+
+        function getSuggestedSymbolForNonexistentModule(name: Identifier, targetModule: Symbol): Symbol | undefined {
+            return targetModule.exports && getSpellingSuggestionForName(idText(name), getExportsOfModuleAsArray(targetModule), SymbolFlags.ModuleMember);
         }
 
-        function getSuggestionForNonexistentModule(name: Identifier, targetModule: Symbol): string | undefined {
-            const suggestion = targetModule.exports && getSpellingSuggestionForName(idText(name), getExportsOfModuleAsArray(targetModule), SymbolFlags.ModuleMember);
+        function getSuggestionForNonexistentExport(name: Identifier, targetModule: Symbol): string | undefined {
+            const suggestion = getSuggestedSymbolForNonexistentModule(name, targetModule);
             return suggestion && symbolName(suggestion);
         }
 

src/compiler/diagnosticMessages.json

@@ -2401,8 +2401,8 @@
         "category": "Error",
         "code": 2727
     },
-    "'{0}' was declared here.": {
-        "category": "Error",
+    "'{0}' is declared here.": {
+        "category": "Message",
         "code": 2728
     },
     "Property '{0}' is used before its initialization.": {
@@ -3886,7 +3886,7 @@
         "code": 7037
     },
     "Type originates at this import. A namespace-style import cannot be called or constructed, and will cause a failure at runtime. Consider using a default import or import require here instead.": {
-        "category": "Error",
+        "category": "Message",
         "code": 7038
     },
     "Mapped object type implicitly has an 'any' template type.": {

src/compiler/types.ts

@@ -2996,7 +2996,7 @@ namespace ts {
         getApparentType(type: Type): Type;
         getSuggestionForNonexistentProperty(name: Identifier | string, containingType: Type): string | undefined;
         getSuggestionForNonexistentSymbol(location: Node, name: string, meaning: SymbolFlags): string | undefined;
-        getSuggestionForNonexistentModule(node: Identifier, target: Symbol): string | undefined;
+        getSuggestionForNonexistentExport(node: Identifier, target: Symbol): string | undefined;
         getBaseConstraintOfType(type: Type): Type | undefined;
         getDefaultFromTypeParameter(type: Type): Type | undefined;
 

src/services/codefixes/fixSpelling.ts

@@ -43,7 +43,7 @@ namespace ts.codefix {
             const importDeclaration = findAncestor(node, isImportDeclaration)!;
             const resolvedSourceFile = getResolvedSourceFileFromImportDeclaration(sourceFile, context, importDeclaration);
             if (resolvedSourceFile && resolvedSourceFile.symbol) {
-                suggestion = checker.getSuggestionForNonexistentModule(node as Identifier, resolvedSourceFile.symbol);
+                suggestion = checker.getSuggestionForNonexistentExport(node as Identifier, resolvedSourceFile.symbol);
             }
         }
         else {

tests/baselines/reference/ES5For-of17.errors.txt

@@ -7,7 +7,7 @@ tests/cases/conformance/statements/for-ofStatements/ES5For-of17.ts(3,20): error
         for (let v of [v]) {
                        ~
 !!! error TS2448: Block-scoped variable 'v' used before its declaration.
-!!! related TS2728 tests/cases/conformance/statements/for-ofStatements/ES5For-of17.ts:3:14: 'v' was declared here.
+!!! related TS2728 tests/cases/conformance/statements/for-ofStatements/ES5For-of17.ts:3:14: 'v' is declared here.
             var x = v;
             v++;
         }

tests/baselines/reference/ES5For-of20.errors.txt

@@ -8,7 +8,7 @@ tests/cases/conformance/statements/for-ofStatements/ES5For-of20.ts(4,15): error
         for (let v of [v]) {
                        ~
 !!! error TS2448: Block-scoped variable 'v' used before its declaration.
-!!! related TS2728 tests/cases/conformance/statements/for-ofStatements/ES5For-of20.ts:3:14: 'v' was declared here.
+!!! related TS2728 tests/cases/conformance/statements/for-ofStatements/ES5For-of20.ts:3:14: 'v' is declared here.
             const v;
                   ~
 !!! error TS1155: 'const' declarations must be initialized.

tests/baselines/reference/ModuleAndClassWithSameNameAndCommonRoot.errors.txt

@@ -32,7 +32,7 @@ tests/cases/conformance/internalModules/DeclarationMerging/simple.ts(2,31): erro
         export var Instance = new A();
                                   ~
 !!! error TS2449: Class 'A' used before its declaration.
-!!! related TS2728 tests/cases/conformance/internalModules/DeclarationMerging/simple.ts:6:7: 'A' was declared here.
+!!! related TS2728 tests/cases/conformance/internalModules/DeclarationMerging/simple.ts:6:7: 'A' is declared here.
     }
 
     // duplicate identifier

tests/baselines/reference/ModuleWithExportedAndNonExportedFunctions.errors.txt

@@ -35,4 +35,5 @@ tests/cases/conformance/internalModules/exportDeclarations/ModuleWithExportedAnd
 !!! error TS2339: Property 'fn2' does not exist on type 'typeof A'.
     var fng2 = A.fng2;
                  ~~~~
-!!! error TS2551: Property 'fng2' does not exist on type 'typeof A'. Did you mean 'fng'?
+!!! error TS2551: Property 'fng2' does not exist on type 'typeof A'. Did you mean 'fng'?
+!!! related TS2728 tests/cases/conformance/internalModules/exportDeclarations/ModuleWithExportedAndNonExportedFunctions.ts:7:21: 'fng' is declared here.

tests/baselines/reference/anonymousClassExpression2.errors.txt

@@ -17,6 +17,7 @@ tests/cases/compiler/anonymousClassExpression2.ts(13,18): error TS2551: Property
                 this.methodA; // error
                      ~~~~~~~
 !!! error TS2551: Property 'methodA' does not exist on type 'B'. Did you mean 'methodB'?
+!!! related TS2728 tests/cases/compiler/anonymousClassExpression2.ts:12:9: 'methodB' is declared here.
                 this.methodB; // ok
             }
         }

tests/baselines/reference/api/tsserverlibrary.d.ts

@@ -2675,7 +2675,7 @@ declare namespace ts {
         getApparentType(type: Type): Type;
         getSuggestionForNonexistentProperty(name: Identifier | string, containingType: Type): string | undefined;
         getSuggestionForNonexistentSymbol(location: Node, name: string, meaning: SymbolFlags): string | undefined;
-        getSuggestionForNonexistentModule(node: Identifier, target: Symbol): string | undefined;
+        getSuggestionForNonexistentExport(node: Identifier, target: Symbol): string | undefined;
         getBaseConstraintOfType(type: Type): Type | undefined;
         getDefaultFromTypeParameter(type: Type): Type | undefined;
         getAnyType(): Type;
@@ -5430,7 +5430,7 @@ declare namespace ts {
         Class_name_cannot_be_Object_when_targeting_ES5_with_module_0: DiagnosticMessage;
         Cannot_find_lib_definition_for_0: DiagnosticMessage;
         Cannot_find_lib_definition_for_0_Did_you_mean_1: DiagnosticMessage;
-        _0_was_declared_here: DiagnosticMessage;
+        _0_is_declared_here: DiagnosticMessage;
         Property_0_is_used_before_its_initialization: DiagnosticMessage;
         Import_declaration_0_is_using_private_name_1: DiagnosticMessage;
         Type_parameter_0_of_exported_class_has_or_is_using_private_name_1: DiagnosticMessage;

tests/baselines/reference/api/typescript.d.ts

@@ -1920,7 +1920,7 @@ declare namespace ts {
         getApparentType(type: Type): Type;
         getSuggestionForNonexistentProperty(name: Identifier | string, containingType: Type): string | undefined;
         getSuggestionForNonexistentSymbol(location: Node, name: string, meaning: SymbolFlags): string | undefined;
-        getSuggestionForNonexistentModule(node: Identifier, target: Symbol): string | undefined;
+        getSuggestionForNonexistentExport(node: Identifier, target: Symbol): string | undefined;
         getBaseConstraintOfType(type: Type): Type | undefined;
         getDefaultFromTypeParameter(type: Type): Type | undefined;
         /**

tests/baselines/reference/assignmentRestElementWithErrorSourceType.errors.txt

@@ -8,4 +8,5 @@ tests/cases/compiler/assignmentRestElementWithErrorSourceType.ts(2,10): error TS
         ~
 !!! error TS2304: Cannot find name 'c'.
              ~~~~~
-!!! error TS2552: Cannot find name 'tupel'. Did you mean 'tuple'?
+!!! error TS2552: Cannot find name 'tupel'. Did you mean 'tuple'?
+!!! related TS2728 tests/cases/compiler/assignmentRestElementWithErrorSourceType.ts:1:5: 'tuple' is declared here.

tests/baselines/reference/baseCheck.errors.txt

@@ -21,6 +21,7 @@ tests/cases/compiler/baseCheck.ts(26,9): error TS2304: Cannot find name 'x'.
             super(0, loc);
                      ~~~
 !!! error TS2552: Cannot find name 'loc'. Did you mean 'ELoc'?
+!!! related TS2728 tests/cases/compiler/baseCheck.ts:2:7: 'ELoc' is declared here.
         }
 
         m() {

tests/baselines/reference/blockScopedBindingUsedBeforeDef.errors.txt

@@ -8,16 +8,16 @@ tests/cases/compiler/blockScopedBindingUsedBeforeDef.ts(8,7): error TS2448: Bloc
     for (let {[a]: a} of [{ }]) continue;
                ~
 !!! error TS2448: Block-scoped variable 'a' used before its declaration.
-!!! related TS2728 tests/cases/compiler/blockScopedBindingUsedBeforeDef.ts:2:16: 'a' was declared here.
+!!! related TS2728 tests/cases/compiler/blockScopedBindingUsedBeforeDef.ts:2:16: 'a' is declared here.
 
     // 2:
     for (let {[a]: a} = { }; false; ) continue;
                ~
 !!! error TS2448: Block-scoped variable 'a' used before its declaration.
-!!! related TS2728 tests/cases/compiler/blockScopedBindingUsedBeforeDef.ts:5:16: 'a' was declared here.
+!!! related TS2728 tests/cases/compiler/blockScopedBindingUsedBeforeDef.ts:5:16: 'a' is declared here.
 
     // 3:
     let {[b]: b} = { };
           ~
 !!! error TS2448: Block-scoped variable 'b' used before its declaration.
-!!! related TS2728 tests/cases/compiler/blockScopedBindingUsedBeforeDef.ts:8:11: 'b' was declared here.
+!!! related TS2728 tests/cases/compiler/blockScopedBindingUsedBeforeDef.ts:8:11: 'b' is declared here.