Fix two related bugs affected by overriding toString methods.

* Properly reference types in overridden `toString` implementations.
  Fixes #438
* Override `toString` in a Fake implementation when the class-to-be-faked has
  a superclass which overrides `toString` with additional parameters.
  Fixes #371

PiperOrigin-RevId: 385852381

Author: srawlins

CHANGELOG.md

@@ -7,6 +7,11 @@
   type, prefer a library which exports the library in which the type is
   declared. This avoids some confusion with conditional exports.
   [#443](https://github.com/dart-lang/mockito/issues/443)
+* Properly reference types in overridden `toString` implementations.
+  [#438](https://github.com/dart-lang/mockito/issues/438)
+* Override `toString` in a Fake implementation when the class-to-be-faked has
+  a superclass which overrides `toString` with additional parameters.
+  [#371](https://github.com/dart-lang/mockito/issues/371)
 * Support analyzer 2.0.0
 
 ## 5.0.11

lib/src/builder.dart

@@ -257,6 +257,21 @@ class _TypeVisitor extends RecursiveElementVisitor<void> {
       type.typeArguments.forEach(_addType);
       if (!alreadyVisitedElement) {
         type.element.typeParameters.forEach(visitTypeParameterElement);
+
+        final toStringMethod =
+            type.element.lookUpMethod('toString', type.element.library);
+        if (toStringMethod != null && toStringMethod.parameters.isNotEmpty) {
+          // In a Fake class which implements a class which overrides `toString`
+          // with additional (optional) parameters, we must also override
+          // `toString` and reference the same types referenced in those
+          // parameters.
+          for (final parameter in toStringMethod.parameters) {
+            final parameterType = parameter.type;
+            if (parameterType is analyzer.InterfaceType) {
+              parameterType.element.accept(this);
+            }
+          }
+        }
       }
     } else if (type is analyzer.FunctionType) {
       _addType(type.returnType);
@@ -1203,9 +1218,9 @@ class _MockClassInfo {
           ..types.addAll(typeParameters);
       }));
 
-      final toStringMethod = elementToFake.methods
-          .firstWhereOrNull((method) => method.name == 'toString');
-      if (toStringMethod != null) {
+      final toStringMethod =
+          elementToFake.lookUpMethod('toString', elementToFake.library);
+      if (toStringMethod != null && toStringMethod.parameters.isNotEmpty) {
         // If [elementToFake] includes an overriding `toString` implementation,
         // we need to include an implementation which matches the signature.
         cBuilder.methods.add(Method(
@@ -1483,7 +1498,8 @@ class _MockClassInfo {
     assert(mockLibraryInfo.assetUris.containsKey(element),
         'An element, "$element", is missing from the asset URI mapping');
 
-    return mockLibraryInfo.assetUris[element]!;
+    return mockLibraryInfo.assetUris[element] ??
+        (throw StateError('Asset URI is missing for $element'));
   }
 
   /// Returns a [Reference] to [symbol] with [url].

test/builder/auto_mocks_test.dart

@@ -687,13 +687,31 @@ void main() {
     );
   });
 
-  test('overrides `toString` with correct signature if the class overrides it',
-      () async {
+  test(
+      'overrides `toString` with a correct signature if the class overrides '
+      'it', () async {
+    await expectSingleNonNullableOutput(
+      dedent('''
+      abstract class Foo {
+        String toString({bool a = false});
+      }
+      '''),
+      _containsAllOf('String toString({bool? a = false}) => super.toString()'),
+    );
+  });
+
+  test(
+      'overrides `toString` with a correct signature if a mixed in class '
+      'overrides it, in a Fake', () async {
     await expectSingleNonNullableOutput(
       dedent('''
       abstract class Foo {
+        Bar m();
+      }
+      abstract class BarBase {
         String toString({bool a = false});
       }
+      abstract class Bar extends BarBase {}
       '''),
       _containsAllOf('String toString({bool? a = false}) => super.toString()'),
     );
@@ -1060,7 +1078,7 @@ void main() {
   });
 
   test(
-      'imports libraries for external class types found in an inherited method'
+      'imports libraries for external class types found in an inherited method '
       'via a generic instantiation', () async {
     await testWithNonNullable({
       ...annotationsAsset,
@@ -2285,6 +2303,21 @@ void main() {
     );
   });
 
+  test('imports libraries for types used in generated fake classes', () async {
+    await expectSingleNonNullableOutput(
+      dedent('''
+      class Foo {
+        Bar m1() => Bar('name1');
+      }
+      class Bar {
+        String toString({Baz? baz}) => '';
+      }
+      class Baz {}
+      '''),
+      _containsAllOf('String toString({_i2.Baz? baz}) => super.toString();'),
+    );
+  });
+
   test('deduplicates fake classes', () async {
     var mocksContent = await buildWithSingleNonNullableSource(dedent(r'''
       class Foo {