Use internally more precise types for typeParameters, remove many casts.

Change-Id: I559a5f582a2e1fce6173635da1e1bbad87c6fafb
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/440543
Reviewed-by: Konstantin Shcheglov <[email protected]>
Commit-Queue: Paul Berry <[email protected]>
Reviewed-by: Paul Berry <[email protected]>

Author: fshcheglov

pkg/analyzer/lib/src/dart/element/element.dart

@@ -2130,6 +2130,9 @@ abstract class ExecutableElement2OrMember implements ExecutableElement {
 
   @override
   FunctionTypeImpl get type;
+
+  @override
+  List<TypeParameterElementImpl> get typeParameters;
 }
 
 abstract class ExecutableElementImpl extends FunctionTypedElementImpl
@@ -2223,7 +2226,7 @@ abstract class ExecutableElementImpl extends FunctionTypedElementImpl
   @override
   FunctionTypeImpl get type {
     return _type ??= FunctionTypeImpl(
-      typeParameters: typeParameters.cast(),
+      typeParameters: typeParameters,
       parameters: formalParameters,
       returnType: returnType,
       nullabilitySuffix: NullabilitySuffix.none,
@@ -3127,13 +3130,13 @@ class FormalParameterElementImpl extends PromotableElementImpl
 
   @override
   // TODO(augmentations): Implement the merge of formal parameters.
-  List<TypeParameterElement> get typeParameters =>
+  List<TypeParameterElementImpl> get typeParameters =>
       firstFragment.typeParameters.map((fragment) => fragment.element).toList();
 
   @Deprecated('Use typeParameters instead')
   @override
   // TODO(augmentations): Implement the merge of formal parameters.
-  List<TypeParameterElement> get typeParameters2 => typeParameters;
+  List<TypeParameterElementImpl> get typeParameters2 => typeParameters;
 
   @override
   TypeImpl get typeShared => type;
@@ -3182,6 +3185,9 @@ mixin FormalParameterElementMixin
   @override
   TypeImpl get type;
 
+  @override
+  List<TypeParameterElementImpl> get typeParameters;
+
   @override
   void appendToWithoutDelimiters(StringBuffer buffer) {
     buffer.write(type.getDisplayString());
@@ -3533,18 +3539,18 @@ mixin FragmentedTypeParameterizedElementMixin<E extends FragmentImpl>
     return true;
   }
 
-  List<TypeParameterElement> get typeParameters {
+  List<TypeParameterElementImpl> get typeParameters {
     var fragment = firstFragment;
     if (fragment is TypeParameterizedFragmentMixin) {
       return fragment.typeParameters
-          .map((fragment) => (fragment as TypeParameterFragment).element)
+          .map((fragment) => fragment.element)
           .toList();
     }
     return const [];
   }
 
   @Deprecated('Use typeParameters instead')
-  List<TypeParameterElement> get typeParameters2 {
+  List<TypeParameterElementImpl> get typeParameters2 {
     return typeParameters;
   }
 }
@@ -6912,10 +6918,9 @@ class LocalFunctionElementImpl extends ExecutableElementImpl
   String? get name3 => name;
 
   @override
-  List<TypeParameterElement> get typeParameters =>
-      _wrappedFragment.typeParameters
-          .map((fragment) => (fragment as TypeParameterFragment).element)
-          .toList();
+  List<TypeParameterElementImpl> get typeParameters {
+    return firstFragment.typeParameters.map((fragment) => fragment.element).toList();
+  }
 
   @Deprecated('Use typeParameters instead')
   @override
@@ -8693,6 +8698,9 @@ abstract class PropertyAccessorElementImpl extends ExecutableElementImpl
   @override
   String? get name3 => name;
 
+  @override
+  List<TypeParameterElementImpl> get typeParameters;
+
   @override
   @trackedDirectly
   PropertyInducingElementImpl? get variable {

pkg/analyzer/lib/src/dart/element/inheritance_manager3.dart

@@ -983,7 +983,7 @@ class InheritanceManager3 {
           transformedParameters.map((e) => e.firstFragment).toList();
       resultFragment.typeParameters =
           executable.typeParameters
-              .map((e) => e.firstFragment as TypeParameterFragmentImpl)
+              .map((e) => e.firstFragment)
               .toList();
 
       var elementName = executable.name!;

pkg/analyzer/lib/src/dart/element/member.dart

@@ -383,7 +383,7 @@ class FieldFormalParameterMember extends ParameterMember
     required MapSubstitution substitution,
   }) {
     var freshTypeParameters = _SubstitutedTypeParameters(
-      baseElement.typeParameters.cast(),
+      baseElement.typeParameters,
       substitution,
     );
     return FieldFormalParameterMember._(
@@ -767,8 +767,7 @@ class MethodMember extends ExecutableMember implements MethodElement2OrMember {
     required MapSubstitution substitution,
   }) {
     var freshTypeParameters = _SubstitutedTypeParameters(
-      // TODO(scheglov): avoid the cast
-      baseElement.typeParameters.cast(),
+      baseElement.typeParameters,
       substitution,
     );
     return MethodMember._(
@@ -846,7 +845,7 @@ class ParameterMember extends VariableMember with FormalParameterElementMixin {
     required MapSubstitution substitution,
   }) {
     var freshTypeParameters = _SubstitutedTypeParameters(
-      baseElement.typeParameters.cast(),
+      baseElement.typeParameters,
       substitution,
     );
     return ParameterMember._(
@@ -1041,8 +1040,7 @@ abstract class PropertyAccessorMember extends ExecutableMember
     required MapSubstitution substitution,
   }) {
     var freshTypeParameters = _SubstitutedTypeParameters(
-      // TODO(scheglov): avoid the cast
-      baseElement.typeParameters.cast(),
+      baseElement.typeParameters,
       substitution,
     );
     if (baseElement is GetterElementImpl) {
@@ -1191,7 +1189,7 @@ class SuperFormalParameterMember extends ParameterMember
     required MapSubstitution substitution,
   }) {
     var freshTypeParameters = _SubstitutedTypeParameters(
-      baseElement.typeParameters.cast(),
+      baseElement.typeParameters,
       substitution,
     );
     return SuperFormalParameterMember._(

pkg/analyzer/lib/src/dart/resolver/extension_member_resolver.dart

@@ -384,7 +384,7 @@ class ExtensionMemberResolver {
       }
     } else {
       inferenceLogWriter?.enterGenericInference(
-        typeParameters.cast(),
+        typeParameters,
         element.extendedType,
       );
       var inferrer = GenericInferrer(

pkg/analyzer/lib/src/dart/resolver/typed_literal_resolver.dart

@@ -331,9 +331,7 @@ class TypedLiteralResolver {
       var iterableType = unwrappedContextType.asInstanceOf(
         _typeProvider.iterableElement,
       );
-      var mapType = unwrappedContextType.asInstanceOf(
-        _typeProvider.mapElement,
-      );
+      var mapType = unwrappedContextType.asInstanceOf(_typeProvider.mapElement);
       var isIterable = iterableType != null;
       var isMap = mapType != null;
 
@@ -474,12 +472,7 @@ class TypedLiteralResolver {
   }) {
     var element = _typeProvider.listElement;
     var typeParameters = element.typeParameters;
-    inferenceLogWriter?.enterGenericInference(
-      // TODO(paulberry): make this cast unnecessary by changing
-      // `TypeProviderImpl.listElement2` to `ClassElementImpl2`.
-      typeParameters.cast(),
-      element.thisType,
-    );
+    inferenceLogWriter?.enterGenericInference(typeParameters, element.thisType);
 
     return _typeSystem.setupGenericTypeInference(
       typeParameters: typeParameters,
@@ -549,9 +542,7 @@ class TypedLiteralResolver {
   ) {
     var element = _typeProvider.mapElement;
     inferenceLogWriter?.enterGenericInference(
-      // TODO(paulberry): make this cast unnecessary by changing
-      // `TypeProviderImpl.mapElement2` to `ClassElementImpl2`.
-      element.typeParameters.cast(),
+      element.typeParameters,
       element.thisType,
     );
     return _typeSystem.setupGenericTypeInference(
@@ -662,9 +653,7 @@ class TypedLiteralResolver {
   ) {
     var element = _typeProvider.setElement;
     inferenceLogWriter?.enterGenericInference(
-      // TODO(paulberry): make this cast unnecessary by changing
-      // `TypeProviderImpl.setElement2` to `ClassElementImpl2`.
-      element.typeParameters.cast(),
+      element.typeParameters,
       element.thisType,
     );
     return _typeSystem.setupGenericTypeInference(

pkg/analyzer/lib/src/summary2/bundle_reader.dart

@@ -927,8 +927,7 @@ class LibraryReader {
               element.enclosingElement as InstanceElementImpl;
           reader._addTypeParameters2(enclosingElement.typeParameters);
 
-          // TODO(scheglov): remove cast
-          reader._addTypeParameters2(element.typeParameters.cast());
+          reader._addTypeParameters2(element.typeParameters);
 
           element.returnType = reader.readRequiredType();
         }),
@@ -1206,8 +1205,7 @@ class LibraryReader {
 
       element.deferReadResolution(
         _createDeferredReadResolutionCallback((reader) {
-          // TODO(scheglov): remove cast
-          reader._addTypeParameters2(element.typeParameters.cast());
+          reader._addTypeParameters2(element.typeParameters);
 
           element.returnType = reader.readRequiredType();
         }),
@@ -1308,8 +1306,7 @@ class LibraryReader {
 
       element.deferReadResolution(
         _createDeferredReadResolutionCallback((reader) {
-          // TODO(scheglov): remove cast
-          reader._addTypeParameters2(element.typeParameters.cast());
+          reader._addTypeParameters2(element.typeParameters);
           element.aliasedType = reader.readRequiredType();
         }),
       );

pkg/analyzer/lib/src/summary2/bundle_writer.dart

@@ -200,8 +200,7 @@ class BundleWriter {
       _sink.writeList(element.fragments, _writeFragmentId);
 
       _writeElementResolution(() {
-        // TODO(scheglov): avoid cast
-        _resolutionSink.withTypeParameters(element.typeParameters.cast(), () {
+        _resolutionSink.withTypeParameters(element.typeParameters, () {
           _resolutionSink.writeType(element.returnType);
           _resolutionSink.writeElement(element.superConstructor);
           _resolutionSink.writeElement(element.redirectedConstructor);
@@ -548,8 +547,7 @@ class BundleWriter {
       _sink._writeTopLevelInferenceError(element.typeInferenceError);
 
       _writeElementResolution(() {
-        // TODO(scheglov): avoid cast
-        _resolutionSink.withTypeParameters(element.typeParameters.cast(), () {
+        _resolutionSink.withTypeParameters(element.typeParameters, () {
           _resolutionSink.writeType(element.returnType);
           // TODO(scheglov): formal parameters
         });
@@ -720,7 +718,7 @@ class BundleWriter {
       _sink.writeList(element.fragments, _writeFragmentId);
 
       _writeElementResolution(() {
-        _resolutionSink.withTypeParameters(element.typeParameters.cast(), () {
+        _resolutionSink.withTypeParameters(element.typeParameters, () {
           _resolutionSink.writeType(element.returnType);
         });
       });
@@ -749,7 +747,7 @@ class BundleWriter {
       _sink.writeList(element.fragments, _writeFragmentId);
 
       _writeElementResolution(() {
-        _resolutionSink.withTypeParameters(element.typeParameters.cast(), () {
+        _resolutionSink.withTypeParameters(element.typeParameters, () {
           _resolutionSink.writeType(element.aliasedType);
         });
       });
@@ -1034,7 +1032,7 @@ class ResolutionSink extends _SummaryDataWriter {
       _writeFormalParameterKind2(parameter);
       writeBool(parameter.hasImplicitType);
       writeBool(parameter.isInitializingFormal);
-      _writeTypeParameters2(parameter.typeParameters.cast(), () {
+      _writeTypeParameters2(parameter.typeParameters, () {
         writeType(parameter.type);
         _writeElementName(parameter);
         _writeFormalParameters2(

pkg/analyzer/lib/src/summary2/instance_member_inferrer.dart

@@ -759,8 +759,7 @@ class InstanceMemberInferrer {
 
     return replaceTypeParameters(
       overriddenType,
-      // TODO(scheglov): remove this cast
-      elementTypeParameters.cast(),
+      elementTypeParameters,
     );
   }
 

pkg/analyzer/test/src/dart/element/type_constraint_gatherer_test.dart

@@ -2,7 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/src/dart/element/element.dart';
 import 'package:analyzer/src/dart/element/type.dart';
 import 'package:analyzer/src/dart/element/type_constraint_gatherer.dart';
@@ -1058,14 +1057,14 @@ class TypeConstraintGathererTest extends AbstractTypeSystemTest {
   }
 
   void _checkMatch(
-    List<TypeParameterElement> typeParameters,
+    List<TypeParameterElementImpl> typeParameters,
     TypeImpl P,
     TypeImpl Q,
     bool leftSchema,
     List<String> expected,
   ) {
     var gatherer = TypeConstraintGatherer(
-      typeParameters: typeParameters.cast(),
+      typeParameters: typeParameters,
       typeSystemOperations: TypeSystemOperations(
         typeSystem,
         strictCasts: false,
@@ -1094,13 +1093,13 @@ class TypeConstraintGathererTest extends AbstractTypeSystemTest {
   }
 
   void _checkNotMatch(
-    List<TypeParameterElement> typeParameters,
+    List<TypeParameterElementImpl> typeParameters,
     TypeImpl P,
     TypeImpl Q,
     bool leftSchema,
   ) {
     var gatherer = TypeConstraintGatherer(
-      typeParameters: typeParameters.cast(),
+      typeParameters: typeParameters,
       typeSystemOperations: TypeSystemOperations(
         typeSystem,
         strictCasts: false,