fix(49964): Incorrect code generated by "add extends constraint" fix for multiple usages of the same type parameter

src/services/codefixes/fixAddMissingConstraint.ts

@@ -16,50 +16,104 @@ namespace ts.codefix {
     registerCodeFix({
         errorCodes,
         getCodeActions(context) {
-            const { sourceFile, span, program } = context;
-            const related = getDiagnosticRelatedInfo(program, sourceFile, span);
-            if (!related) {
-                return;
-            }
-            const changes = textChanges.ChangeTracker.with(context, t => addMissingConstraint(t, related));
+            const { sourceFile, span, program, preferences, host } = context;
+            const info = getInfo(program, sourceFile, span);
+            if (info === undefined) return;
+
+            const changes = textChanges.ChangeTracker.with(context, t => addMissingConstraint(t, program, preferences, host, sourceFile, info));
             return [createCodeFixAction(fixId, changes, Diagnostics.Add_extends_constraint, fixId, Diagnostics.Add_extends_constraint_to_all_type_parameters)];
         },
         fixIds: [fixId],
-        getAllCodeActions: context => codeFixAll(context, errorCodes, (changes, diag) => {
-            const info = getDiagnosticRelatedInfo(context.program, context.sourceFile, diag);
-            if (!info) return;
-            return addMissingConstraint(changes, info);
-        }),
+        getAllCodeActions: context => {
+            const { program, preferences, host } = context;
+            const seen = new Map<string, true>();
+
+            return createCombinedCodeActions(textChanges.ChangeTracker.with(context, changes => {
+                eachDiagnostic(context, errorCodes, diag => {
+                    const info = getInfo(program, diag.file, createTextSpan(diag.start, diag.length));
+                    if (info) {
+                        const id = getNodeId(info.declaration) + "#" + info.token.getText();
+                        if (addToSeen(seen, id)) {
+                            return addMissingConstraint(changes, program, preferences, host, diag.file, info);
+                        }
+                    }
+                    return undefined;
+                });
+            }));
+        }
     });
 
-    function getDiagnosticRelatedInfo(program: Program, sourceFile: SourceFile, span: TextSpan) {
+    interface Info {
+        constraint: Type | string;
+        declaration: TypeParameterDeclaration;
+        token: Node;
+    }
+
+    function getInfo(program: Program, sourceFile: SourceFile, span: TextSpan): Info | undefined {
         const diag = find(program.getSemanticDiagnostics(sourceFile), diag => diag.start === span.start && diag.length === span.length);
-        if (!diag || !diag.relatedInformation) return;
+        if (diag === undefined || diag.relatedInformation === undefined) return;
+
         const related = find(diag.relatedInformation, related => related.code === Diagnostics.This_type_parameter_might_need_an_extends_0_constraint.code);
-        if (!related) return;
-        return related;
-    }
+        if (related === undefined || related.file === undefined || related.start === undefined || related.length === undefined) return;
+
+        let declaration = findAncestorMatchingSpan(related.file, createTextSpan(related.start, related.length));
+        if (declaration === undefined) return;
 
-    function addMissingConstraint(changes: textChanges.ChangeTracker, related: DiagnosticRelatedInformation): void {
-        let decl = findAncestorMatchingSpan(related.file!, related as TextSpan);
-        if (!decl) return;
-        if (isIdentifier(decl) && isTypeParameterDeclaration(decl.parent)) {
-            decl = decl.parent;
+        if (isIdentifier(declaration) && isTypeParameterDeclaration(declaration.parent)) {
+            declaration = declaration.parent;
         }
-        if (!isTypeParameterDeclaration(decl) || isMappedTypeNode(decl.parent)) return; // should only issue fix on type parameters written using `extends`
-        const newConstraint = flattenDiagnosticMessageText(related.messageText, "\n", 0).match(/`extends (.*)`/);
-        if (!newConstraint) return;
-        const newConstraintText = newConstraint[1];
 
-        changes.insertText(related.file!, decl.name.end, ` extends ${newConstraintText}`);
+        if (isTypeParameterDeclaration(declaration)) {
+            // should only issue fix on type parameters written using `extends`
+            if (isMappedTypeNode(declaration.parent)) return;
+
+            const token = getTokenAtPosition(sourceFile, span.start);
+            const checker = program.getTypeChecker();
+            const constraint = tryGetConstraintType(checker, token) || tryGetConstraintFromDiagnosticMessage(related.messageText);
+
+            return { constraint, declaration, token };
+        }
+        return undefined;
+    }
+
+    function addMissingConstraint(changes: textChanges.ChangeTracker, program: Program, preferences: UserPreferences, host: LanguageServiceHost, sourceFile: SourceFile, info: Info): void {
+        const { declaration, constraint } = info;
+        const checker = program.getTypeChecker();
+
+        if (isString(constraint)) {
+            changes.insertText(sourceFile, declaration.name.end, ` extends ${constraint}`);
+        }
+        else {
+            const scriptTarget = getEmitScriptTarget(program.getCompilerOptions());
+            const tracker = getNoopSymbolTrackerWithResolver({ program, host });
+            const importAdder = createImportAdder(sourceFile, program, preferences, host);
+            const typeNode = typeToAutoImportableTypeNode(checker, importAdder, constraint, /*contextNode*/ undefined, scriptTarget, /*flags*/ undefined, tracker);
+            if (typeNode) {
+                changes.replaceNode(sourceFile, declaration, factory.updateTypeParameterDeclaration(declaration, /*modifiers*/ undefined, declaration.name, typeNode, declaration.default));
+                importAdder.writeFixes(changes);
+            }
+        }
     }
 
     function findAncestorMatchingSpan(sourceFile: SourceFile, span: TextSpan): Node {
-        let token = getTokenAtPosition(sourceFile, span.start);
         const end = textSpanEnd(span);
+        let token = getTokenAtPosition(sourceFile, span.start);
         while (token.end < end) {
             token = token.parent;
         }
         return token;
     }
+
+    function tryGetConstraintFromDiagnosticMessage(messageText: string | DiagnosticMessageChain) {
+        const [_, constraint] = flattenDiagnosticMessageText(messageText, "\n", 0).match(/`extends (.*)`/) || [];
+        return constraint;
+    }
+
+    function tryGetConstraintType(checker: TypeChecker, node: Node) {
+        if (isTypeNode(node.parent)) {
+            return checker.getTypeArgumentConstraint(node.parent);
+        }
+        const contextualType = isExpression(node) ? checker.getContextualType(node) : undefined;
+        return contextualType || checker.getTypeAtLocation(node);
+    }
 }

tests/cases/fourslash/quickfixAddMissingConstraint4.ts

@@ -0,0 +1,24 @@
+/// <reference path="fourslash.ts" />
+
+// @filename: /bar.ts
+////export type Bar = Record<string, string>
+////export function bar<T extends Bar>(obj: { prop: T }) {}
+
+// @filename: /foo.ts
+////import { bar } from "./bar";
+////
+////export function foo<T>(x: T) {
+////    bar({ prop: x/**/ })
+////}
+
+goTo.marker("");
+verify.codeFix({
+    index: 0,
+    description: "Add `extends` constraint.",
+    newFileContent:
+`import { bar } from "./bar";
+
+export function foo<T extends Bar>(x: T) {
+    bar({ prop: x })
+}`
+});

tests/cases/fourslash/quickfixAddMissingConstraint_all.ts

@@ -0,0 +1,65 @@
+/// <reference path="fourslash.ts" />
+
+// @strict: true
+
+// @filename: /bar.ts
+////export type Bar = Record<string, string>
+////export function bar<T extends Bar>(obj: { prop: T }) {}
+
+// @filename: /foo.ts
+////import { bar } from "./bar";
+////
+////export function f1<T>(x: T) {
+////    bar({ prop: x })
+////}
+////
+////function f2<T>(x: T) {
+////    const y: `${number}` = x;
+////}
+////
+////interface Fn<T extends string> {}
+////function f3<T>(x: Fn<T>) {
+////}
+////
+////function f4<T = `${number}`>(x: T) {
+////    const y: `${number}` = x;
+////}
+////
+////interface TypeRef<T extends {}> {
+////    x: T
+////}
+////function f5<T>(): TypeRef</**/T> {
+////    throw undefined as any as TypeRef<T>;
+////}
+
+goTo.file("/foo.ts");
+verify.codeFixAll({
+    fixId: "addMissingConstraint",
+    fixAllDescription: ts.Diagnostics.Add_extends_constraint_to_all_type_parameters.message,
+    newFileContent:
+"import { bar } from \"./bar\";\n\n" +
+
+"export function f1<T extends Bar>(x: T) {\n" +
+"    bar({ prop: x })\n" +
+"}\n\n" +
+
+"function f2<T extends \`${number}\`>(x: T) {\n" +
+"    const y: `${number}` = x;\n" +
+"}\n\n" +
+
+"interface Fn<T extends string> {}\n" +
+"function f3<T extends string>(x: Fn<T>) {\n" +
+"}\n\n" +
+
+"function f4<T extends `${number}` = `${number}`>(x: T) {\n" +
+"    const y: `${number}` = x;\n" +
+"}\n\n" +
+
+"interface TypeRef<T extends {}> {\n" +
+"    x: T\n" +
+"}\n" +
+"function f5<T extends {}>(): TypeRef<T> {\n" +
+"    throw undefined as any as TypeRef<T>;\n" +
+"}"
+
+});