Merge pull request #25359 from Microsoft/useBeforeDeclareRelatedSpans

Related error spans on "used before declared" error messages

Author: DanielRosenwasser

src/compiler/checker.ts

@@ -1655,14 +1655,25 @@ namespace ts {
             if (declaration === undefined) return Debug.fail("Declaration to checkResolvedBlockScopedVariable is undefined");
 
             if (!(declaration.flags & NodeFlags.Ambient) && !isBlockScopedNameDeclaredBeforeUse(declaration, errorLocation)) {
+                let diagnosticMessage;
+                const declarationName = declarationNameToString(getNameOfDeclaration(declaration));
                 if (result.flags & SymbolFlags.BlockScopedVariable) {
-                    error(errorLocation, Diagnostics.Block_scoped_variable_0_used_before_its_declaration, declarationNameToString(getNameOfDeclaration(declaration)));
+                    diagnosticMessage = error(errorLocation, Diagnostics.Block_scoped_variable_0_used_before_its_declaration, declarationName);
                 }
                 else if (result.flags & SymbolFlags.Class) {
-                    error(errorLocation, Diagnostics.Class_0_used_before_its_declaration, declarationNameToString(getNameOfDeclaration(declaration)));
+                    diagnosticMessage = error(errorLocation, Diagnostics.Class_0_used_before_its_declaration, declarationName);
                 }
                 else if (result.flags & SymbolFlags.RegularEnum) {
-                    error(errorLocation, Diagnostics.Enum_0_used_before_its_declaration, declarationNameToString(getNameOfDeclaration(declaration)));
+                    diagnosticMessage = error(errorLocation, Diagnostics.Enum_0_used_before_its_declaration, declarationName);
+                }
+                else {
+                    Debug.assert(!!(result.flags & SymbolFlags.ConstEnum));
+                }
+
+                if (diagnosticMessage) {
+                    addRelatedInfo(diagnosticMessage,
+                        createDiagnosticForNode(declaration, Diagnostics._0_was_declared_here, declarationName)
+                    );
                 }
             }
         }
@@ -17460,16 +17471,24 @@ namespace ts {
                 return;
             }
 
+            let diagnosticMessage;
+            const declarationName = idText(right);
             if (isInPropertyInitializer(node) &&
                 !isBlockScopedNameDeclaredBeforeUse(valueDeclaration, right)
                 && !isPropertyDeclaredInAncestorClass(prop)) {
-                error(right, Diagnostics.Block_scoped_variable_0_used_before_its_declaration, idText(right));
+                diagnosticMessage = error(right, Diagnostics.Block_scoped_variable_0_used_before_its_declaration, declarationName);
             }
             else if (valueDeclaration.kind === SyntaxKind.ClassDeclaration &&
                 node.parent.kind !== SyntaxKind.TypeReference &&
                 !(valueDeclaration.flags & NodeFlags.Ambient) &&
                 !isBlockScopedNameDeclaredBeforeUse(valueDeclaration, right)) {
-                error(right, Diagnostics.Class_0_used_before_its_declaration, idText(right));
+                diagnosticMessage = error(right, Diagnostics.Class_0_used_before_its_declaration, declarationName);
+            }
+
+            if (diagnosticMessage) {
+                addRelatedInfo(diagnosticMessage,
+                    createDiagnosticForNode(valueDeclaration, Diagnostics._0_was_declared_here, declarationName)
+                );
             }
         }
 
@@ -19083,8 +19102,8 @@ namespace ts {
             if (importNode && !isImportCall(importNode)) {
                 const sigs = getSignaturesOfType(getTypeOfSymbol(getSymbolLinks(apparentType.symbol).target!), kind);
                 if (!sigs || !sigs.length) return;
-                diagnostic.relatedInformation = diagnostic.relatedInformation || [];
-                diagnostic.relatedInformation.push(createDiagnosticForNode(importNode, Diagnostics.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));
+                Debug.assert(!diagnostic.relatedInformation);
+                diagnostic.relatedInformation = [createDiagnosticForNode(importNode, Diagnostics.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)];
             }
         }
 

src/compiler/diagnosticMessages.json

@@ -2397,6 +2397,10 @@
         "category": "Error",
         "code": 2727
     },
+    "'{0}' was declared here.": {
+        "category": "Error",
+        "code": 2728
+    },
 
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",

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

@@ -7,6 +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.
             var x = v;
             v++;
         }

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

@@ -8,6 +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.
             const v;
                   ~
 !!! error TS1155: 'const' declarations must be initialized.

tests/baselines/reference/ModuleAndClassWithSameNameAndCommonRoot.errors.txt

@@ -32,6 +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.
     }
 
     // duplicate identifier

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

@@ -5418,6 +5418,7 @@ 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;
         Import_declaration_0_is_using_private_name_1: DiagnosticMessage;
         Type_parameter_0_of_exported_class_has_or_is_using_private_name_1: DiagnosticMessage;
         Type_parameter_0_of_exported_interface_has_or_is_using_private_name_1: DiagnosticMessage;

tests/baselines/reference/blockScopedBindingUsedBeforeDef.errors.txt

@@ -8,13 +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.
 
     // 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.
 
     // 3:
     let {[b]: b} = { };
           ~
-!!! error TS2448: Block-scoped variable 'b' used before its declaration.
+!!! error TS2448: Block-scoped variable 'b' used before its declaration.
+!!! related TS2728 tests/cases/compiler/blockScopedBindingUsedBeforeDef.ts:8:11: 'b' was declared here.

tests/baselines/reference/blockScopedVariablesUseBeforeDef.errors.txt

@@ -9,6 +9,7 @@ tests/cases/compiler/blockScopedVariablesUseBeforeDef.ts(100,12): error TS2448:
         let a = x;
                 ~
 !!! error TS2448: Block-scoped variable 'x' used before its declaration.
+!!! related TS2728 tests/cases/compiler/blockScopedVariablesUseBeforeDef.ts:3:9: 'x' was declared here.
         let x;
     }
 
@@ -67,6 +68,7 @@ tests/cases/compiler/blockScopedVariablesUseBeforeDef.ts(100,12): error TS2448:
             static a = x;
                        ~
 !!! error TS2448: Block-scoped variable 'x' used before its declaration.
+!!! related TS2728 tests/cases/compiler/blockScopedVariablesUseBeforeDef.ts:60:9: 'x' was declared here.
         }
         let x;
     }
@@ -76,6 +78,7 @@ tests/cases/compiler/blockScopedVariablesUseBeforeDef.ts(100,12): error TS2448:
             static a = x;
                        ~
 !!! error TS2448: Block-scoped variable 'x' used before its declaration.
+!!! related TS2728 tests/cases/compiler/blockScopedVariablesUseBeforeDef.ts:67:9: 'x' was declared here.
         }
         let x;
     }
@@ -113,6 +116,7 @@ tests/cases/compiler/blockScopedVariablesUseBeforeDef.ts(100,12): error TS2448:
             a: x 
                ~
 !!! error TS2448: Block-scoped variable 'x' used before its declaration.
+!!! related TS2728 tests/cases/compiler/blockScopedVariablesUseBeforeDef.ts:102:9: 'x' was declared here.
         }
         let x
     }

tests/baselines/reference/circularImportAlias.errors.txt

@@ -9,6 +9,7 @@ tests/cases/conformance/internalModules/importDeclarations/circularImportAlias.t
         export class D extends a.C {
                                  ~
 !!! error TS2449: Class 'C' used before its declaration.
+!!! related TS2728 tests/cases/conformance/internalModules/importDeclarations/circularImportAlias.ts:11:18: 'C' was declared here.
             id: number;
         }
     }

tests/baselines/reference/classAbstractInstantiations2.errors.txt

@@ -45,6 +45,7 @@ tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbst
     var x : any = C;
                   ~
 !!! error TS2449: Class 'C' used before its declaration.
+!!! related TS2728 tests/cases/conformance/classes/classDeclarations/classAbstractKeyword/classAbstractInstantiations2.ts:26:7: 'C' was declared here.
     new x; // okay -- undefined behavior at runtime
 
     class C extends B { } // error -- not declared abstract