[analyzer] Change VariableElementImpl.type setter to TypeImpl.

The types of `LocalVariableElementImpl2.type=`,
`PropertyInducingElementImpl.type=`, and `VariableElementImpl.type=`
are all changed to accept `TypeImpl` rather than `DartType`.

To reduce the number of casts that need to be added, some field types,
getter types, method return types, and method parameter types are
changed to `Impl` types in the following classes:

- `DeclarationBuilder`
- `ElementFactory`
- `ElementsTypesMixin`
- `ForResolver`
- `FunctionExpressionResolver`
- `FunctionTypeBuilder`
- `FunctionTypeTest`
- `InstanceMemberInferrer`
- `LocalVariableElementImpl2`
- `NamedTypeBuilder`
- `NonCovariantTypeParameterPositionVisitorTest`
- `ReplacementVisitor`
- `ResolutionReader`
- `ResolutionVisitor`
- `TypeBuilder`
- `TypeReferencesAnyTest`
- `TypesBuilder`
- `_MockSdkElementsBuilder`
- `_Node`

There is no change to the analyzer public API.

This is part of a larger arc of work to change the analyzer's use of
the shared code so that the type parameters it supplies are not part
of the analyzer public API. See
#59763.

Change-Id: I726bb1ce414eec3f360ae655c1f55e6be9e713fe
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/405242
Reviewed-by: Konstantin Shcheglov <[email protected]>
Commit-Queue: Paul Berry <[email protected]>

Author: stereotype441

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

@@ -7844,9 +7844,9 @@ class LocalVariableElementImpl2 extends PromotableElementImpl2
   Metadata get metadata2 => wrappedElement.metadata2;
 
   @override
-  DartType get type => _wrappedElement.type;
+  TypeImpl get type => _wrappedElement.type;
 
-  set type(DartType type) => _wrappedElement.type = type;
+  set type(TypeImpl type) => _wrappedElement.type = type;
 
   LocalVariableElementImpl get wrappedElement {
     return _wrappedElement;
@@ -9310,7 +9310,9 @@ class ParameterElementImpl extends VariableElementImpl
       nameOffset: -1,
       parameterKind: parameterKind,
     );
-    element.type = type;
+    // TODO(paulberry): remove this cast by changing the type of the `type`
+    // parameter.
+    element.type = type as TypeImpl;
     element.isSynthetic = true;
     return element;
   }
@@ -10357,7 +10359,7 @@ abstract class PropertyInducingElementImpl
   }
 
   @override
-  set type(DartType type) {
+  set type(TypeImpl type) {
     super.type = type;
     // Reset cached types of synthetic getters and setters.
     // TODO(scheglov): Consider not caching these types.
@@ -11630,10 +11632,8 @@ abstract class VariableElementImpl extends ElementImpl
   @override
   TypeImpl get type => _type!;
 
-  set type(DartType type) {
-    // TODO(paulberry): eliminate this cast by changing the setter parameter
-    // type to `TypeImpl`.
-    _type = type as TypeImpl;
+  set type(TypeImpl type) {
+    _type = type;
   }
 
   @override

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

@@ -58,7 +58,7 @@ class ReplacementVisitor
     required FunctionTypeBuilder type,
     required List<TypeParameterElement>? newTypeParameters,
     required List<ParameterElement>? newParameters,
-    required DartType? newReturnType,
+    required TypeImpl? newReturnType,
     required NullabilitySuffix? newNullability,
   }) {
     if (newNullability == null &&
@@ -311,13 +311,15 @@ class ReplacementVisitor
       }
     }
 
-    DartType? visitType(DartType? type) {
+    TypeImpl? visitType(DartType? type) {
       if (type == null) return null;
       var result = type.accept(this);
       if (substitution != null) {
         result = substitution.substituteType(result ?? type);
       }
-      return result;
+      // TODO(paulberry): eliminate this cast by changing `ReplacementVisitor`
+      // to implement `TypeVisitor<TypeImpl?>`.
+      return result as TypeImpl?;
     }
 
     var newReturnType = visitType(node.returnType);

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

@@ -554,7 +554,9 @@ abstract class _TypeSubstitutor
 
     inner.invertVariance();
 
-    var returnType = type.returnType.accept(inner);
+    // TODO(paulberry): eliminate this cast by changing `_TypeSubstitutor` to
+    // implement `TypeVisitor<TypeImpl>`.
+    var returnType = type.returnType.accept(inner) as TypeImpl;
 
     if (useCounter == before) return type;
 

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

@@ -99,7 +99,7 @@ class ForResolver {
   /// a type for the elements being iterated over.  Inference is based
   /// on the type of the iterator or stream over which the foreach loop
   /// is defined.
-  DartType _computeForEachElementType(Expression iterable, bool isAsync) {
+  TypeImpl _computeForEachElementType(ExpressionImpl iterable, bool isAsync) {
     var iterableType = iterable.staticType;
     if (iterableType == null) {
       return InvalidTypeImpl.instance;

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

@@ -80,7 +80,7 @@ class FunctionExpressionResolver {
       return;
     }
 
-    void inferType(ParameterElementImpl p, DartType inferredType) {
+    void inferType(ParameterElementImpl p, TypeImpl inferredType) {
       // Check that there is no declared type, and that we have not already
       // inferred a type in some fashion.
       if (p.hasImplicitType && p.type is DynamicType) {
@@ -108,8 +108,11 @@ class FunctionExpressionResolver {
       Iterator<ParameterElement> fnPositional =
           contextType.parameters.where((p) => p.isPositional).iterator;
       while (positional.moveNext() && fnPositional.moveNext()) {
-        inferType(positional.current as ParameterElementImpl,
-            fnPositional.current.type);
+        inferType(
+            positional.current as ParameterElementImpl,
+            // TODO(paulberry): eliminate this cast by changing the type of
+            // `contextType` to `FunctionTypeImpl`.
+            fnPositional.current.type as TypeImpl);
       }
     }
 
@@ -121,7 +124,11 @@ class FunctionExpressionResolver {
         if (!namedParameterTypes.containsKey(p.name)) {
           continue;
         }
-        inferType(p as ParameterElementImpl, namedParameterTypes[p.name]!);
+        inferType(
+            p as ParameterElementImpl,
+            // TODO(paulberry): eliminate this cast by changing the type of
+            // `contextType` to `FunctionTypeImpl`.
+            namedParameterTypes[p.name]! as TypeImpl);
       }
     }
   }

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

@@ -23,6 +23,7 @@ import 'package:analyzer/src/dart/element/element.dart';
 import 'package:analyzer/src/dart/element/scope.dart';
 import 'package:analyzer/src/dart/element/type.dart';
 import 'package:analyzer/src/dart/element/type_constraint_gatherer.dart';
+import 'package:analyzer/src/dart/element/type_provider.dart';
 import 'package:analyzer/src/dart/resolver/ast_rewrite.dart';
 import 'package:analyzer/src/dart/resolver/flow_analysis_visitor.dart';
 import 'package:analyzer/src/dart/resolver/named_type_resolver.dart';
@@ -73,7 +74,7 @@ class ElementHolder {
 /// 5. Rewrite AST where resolution provides a more accurate understanding.
 class ResolutionVisitor extends RecursiveAstVisitor<void> {
   final LibraryElementImpl _libraryElement;
-  final TypeProvider _typeProvider;
+  final TypeProviderImpl _typeProvider;
   final CompilationUnitElementImpl _unitElement;
   final ErrorReporter _errorReporter;
   final AstRewriter _astRewriter;
@@ -177,7 +178,7 @@ class ResolutionVisitor extends RecursiveAstVisitor<void> {
     this.dataForTesting,
   );
 
-  DartType get _dynamicType => _typeProvider.dynamicType;
+  TypeImpl get _dynamicType => _typeProvider.dynamicType;
 
   @override
   void visitAnnotation(covariant AnnotationImpl node) {
@@ -1402,7 +1403,7 @@ class ResolutionVisitor extends RecursiveAstVisitor<void> {
       var localElement = node.declaredElement as LocalVariableElementImpl;
       element = localElement;
 
-      var varList = node.parent as VariableDeclarationList;
+      var varList = node.parent as VariableDeclarationListImpl;
       localElement.hasImplicitType = varList.type == null;
       localElement.hasInitializer = initializerNode != null;
       localElement.type = varList.type?.type ?? _dynamicType;

pkg/analyzer/lib/src/generated/testing/element_factory.dart

@@ -120,7 +120,7 @@ class ElementFactory {
 
   static ConstructorElementImpl constructorElement(
       ClassElement definingClass, String? name, bool isConst,
-      [List<DartType> argumentTypes = const []]) {
+      [List<TypeImpl> argumentTypes = const []]) {
     var offset = name == null ? -1 : 0;
     // A constructor declared as `C.new` is unnamed, and is modeled as such.
     var constructor = name == null || name == 'new'
@@ -146,11 +146,11 @@ class ElementFactory {
 
   static ConstructorElementImpl constructorElement2(
           ClassElement definingClass, String? name,
-          [List<DartType> argumentTypes = const []]) =>
+          [List<TypeImpl> argumentTypes = const []]) =>
       constructorElement(definingClass, name, false, argumentTypes);
 
   static FieldElementImpl fieldElement(
-      String name, bool isStatic, bool isFinal, bool isConst, DartType type,
+      String name, bool isStatic, bool isFinal, bool isConst, TypeImpl type,
       {ExpressionImpl? initializer}) {
     FieldElementImpl field =
         isConst ? ConstFieldElementImpl(name, 0) : FieldElementImpl(name, 0);
@@ -184,7 +184,7 @@ class ElementFactory {
   }
 
   static PropertyAccessorElementImpl getterElement(
-      String name, bool isStatic, DartType type) {
+      String name, bool isStatic, TypeImpl type) {
     FieldElementImpl field = FieldElementImpl(name, -1);
     field.isStatic = isStatic;
     field.isSynthetic = true;
@@ -227,7 +227,7 @@ class ElementFactory {
       LocalVariableElementImpl(name, 0);
 
   static MethodElementImpl methodElement(String methodName, DartType returnType,
-      [List<DartType> argumentTypes = const []]) {
+      [List<TypeImpl> argumentTypes = const []]) {
     MethodElementImpl method = MethodElementImpl(methodName, 0);
     method.parameters = _requiredParameters(argumentTypes);
     method.returnType = returnType;
@@ -276,7 +276,7 @@ class ElementFactory {
     );
   }
 
-  static ParameterElementImpl namedParameter2(String name, DartType type) {
+  static ParameterElementImpl namedParameter2(String name, TypeImpl type) {
     var parameter = ParameterElementImpl(
       name: name,
       nameOffset: 0,
@@ -294,7 +294,7 @@ class ElementFactory {
     );
   }
 
-  static ParameterElementImpl positionalParameter2(String name, DartType type) {
+  static ParameterElementImpl positionalParameter2(String name, TypeImpl type) {
     var parameter = ParameterElementImpl(
       name: name,
       nameOffset: 0,
@@ -314,7 +314,7 @@ class ElementFactory {
     );
   }
 
-  static ParameterElementImpl requiredParameter2(String name, DartType type) {
+  static ParameterElementImpl requiredParameter2(String name, TypeImpl type) {
     var parameter = ParameterElementImpl(
       name: name,
       nameOffset: 0,
@@ -325,7 +325,7 @@ class ElementFactory {
   }
 
   static PropertyAccessorElementImpl setterElement(
-      String name, bool isStatic, DartType type) {
+      String name, bool isStatic, TypeImpl type) {
     FieldElementImpl field = FieldElementImpl(name, -1);
     field.isStatic = isStatic;
     field.isSynthetic = true;
@@ -367,7 +367,7 @@ class ElementFactory {
   }
 
   static List<ParameterElementImpl> _requiredParameters(
-      List<DartType> argumentTypes) {
+      List<TypeImpl> argumentTypes) {
     var parameters = argumentTypes.mapIndexed((index, type) {
       var parameter = ParameterElementImpl(
         name: 'a$index',

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

@@ -2170,7 +2170,7 @@ class ResolutionReader {
     }
   }
 
-  DartType readRequiredType() {
+  TypeImpl readRequiredType() {
     return readType()!;
   }
 

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

@@ -151,7 +151,7 @@ class _Node extends graph.Node<_Node> {
     _evaluateWithType(type);
   }
 
-  void _evaluateWithType(DartType type) {
+  void _evaluateWithType(TypeImpl type) {
     var typeSystem = element.library.typeSystem;
 
     element.representation.type = type;

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

@@ -23,7 +23,7 @@ class FunctionTypeBuilder extends TypeBuilder {
 
   final List<TypeParameterElement> typeFormals;
   final List<ParameterElement> parameters;
-  final DartType returnType;
+  final TypeImpl returnType;
 
   @override
   final NullabilitySuffix nullabilitySuffix;
@@ -71,7 +71,7 @@ class FunctionTypeBuilder extends TypeBuilder {
   }
 
   @override
-  DartType build() {
+  TypeImpl build() {
     var type = _type;
     if (type != null) {
       return type;
@@ -153,7 +153,7 @@ class FunctionTypeBuilder extends TypeBuilder {
   }
 
   /// If the [type] is a [TypeBuilder], build it; otherwise return as is.
-  static DartType _buildType(DartType type) {
+  static TypeImpl _buildType(TypeImpl type) {
     if (type is TypeBuilder) {
       return type.build();
     } else {
@@ -162,7 +162,7 @@ class FunctionTypeBuilder extends TypeBuilder {
   }
 
   /// Return the type of the [node] as is, possibly a [TypeBuilder].
-  static DartType _getNodeType(TypeAnnotation? node) {
+  static TypeImpl _getNodeType(TypeAnnotation? node) {
     if (node == null) {
       return _dynamicType;
     } else {