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Add DartTypeVisitor and DartType.accept(DartTypeVisitor) to API.
R=brianwilkerson@google.com Bug: #40478 Change-Id: I8453011f4a39323bda86244a749509b4b347b4b6 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/153361 Reviewed-by: Brian Wilkerson <brianwilkerson@google.com> Commit-Queue: Konstantin Shcheglov <scheglov@google.com>
1 parent 42fcc18 commit fea5f58

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+240
-181
lines changed

‎pkg/analyzer/CHANGELOG.md‎

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## 0.39.13-dev
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* Added 'dart/sdk/build_sdk_summary.dart' with `buildSdkSummary`.
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* Added `DynamicType`, `NeverType`, and `VoidType` interfaces.
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* Added `TypeVisitor` and `DartType.accept(TypeVisitor)`.
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## 0.39.12
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* Deprecated `canUseSummaries` in `DartSdkManager` constructor.

‎pkg/analyzer/lib/dart/element/type.dart‎

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/// the references to `String` and `int` are type arguments.
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import 'package:analyzer/dart/element/element.dart';
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import 'package:analyzer/dart/element/nullability_suffix.dart';
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import 'package:analyzer/dart/element/type_visitor.dart';
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import 'package:analyzer/src/dart/element/type.dart' show InterfaceTypeImpl;
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/// The type associated with elements in the element model.
@@ -122,6 +123,9 @@ abstract class DartType {
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/// Return the nullability suffix of this type.
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NullabilitySuffix get nullabilitySuffix;
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/// Use the given [visitor] to visit this type.
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R accept<R>(TypeVisitor<R> visitor);
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/// Return the presentation of this type as it should appear when presented
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/// to users in contexts such as error messages.
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///

‎pkg/analyzer/lib/dart/element/type_visitor.dart‎

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// Copyright (c) 2020, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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import 'package:analyzer/dart/element/type.dart';
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/// Interface for type visitors.
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///
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/// Clients may not extend, implement, or mix-in this class.
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abstract class TypeVisitor<R> {
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const TypeVisitor();
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R visitDynamicType(DynamicType type);
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R visitFunctionType(FunctionType type);
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R visitInterfaceType(InterfaceType type);
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R visitNeverType(NeverType type);
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R visitTypeParameterType(TypeParameterType type);
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R visitVoidType(VoidType type);
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}
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/// Invokes [visitDartType] from any other `visitXyz` method.
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///
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/// Clients may extend this class.
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abstract class UnifyingTypeVisitor<R> implements TypeVisitor<R> {
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const UnifyingTypeVisitor();
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/// By default other `visitXyz` methods invoke this method.
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R visitDartType(DartType type);
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@override
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R visitDynamicType(DynamicType type) => visitDartType(type);
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@override
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R visitFunctionType(FunctionType type) => visitDartType(type);
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@override
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R visitInterfaceType(InterfaceType type) => visitDartType(type);
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@override
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R visitNeverType(NeverType type) => visitDartType(type);
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@override
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R visitTypeParameterType(TypeParameterType type) => visitDartType(type);
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@override
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R visitVoidType(VoidType type) => visitDartType(type);
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}

‎pkg/analyzer/lib/src/dart/constant/has_type_parameter_reference.dart‎

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@@ -8,7 +8,7 @@ import 'package:analyzer/src/dart/element/type_visitor.dart';
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/// Return `true` if the [type] has a type parameter reference.
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bool hasTypeParameterReference(DartType type) {
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var visitor = _ReferencesTypeParameterVisitor();
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DartTypeVisitor.visit(type, visitor);
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type.accept(visitor);
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return visitor.result;
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}
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@@ -23,9 +23,6 @@ class _ReferencesTypeParameterVisitor extends RecursiveTypeVisitor {
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/// The result of whether any type parameters were found.
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bool result = false;
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@override
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bool defaultDartType(_) => true;
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@override
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bool visitTypeParameterType(_) {
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result = true;

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

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import 'package:analyzer/dart/element/nullability_suffix.dart';
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import 'package:analyzer/dart/element/type.dart';
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import 'package:analyzer/src/dart/element/replacement_visitor.dart';
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import 'package:analyzer/src/dart/element/type.dart';
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import 'package:analyzer/src/dart/element/type_provider.dart';
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import 'package:analyzer/src/generated/utilities_dart.dart';
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NullabilityEliminator(this._typeProvider);
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@override
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DartType visitNeverType(NeverTypeImpl type) {
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DartType visitNeverType(NeverType type) {
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return _typeProvider.nullStar;
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}
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return type;
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}
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return NullabilityEliminator(typeProvider).visit(type) ?? type;
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var visitor = NullabilityEliminator(typeProvider);
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return type.accept<DartType>(visitor) ?? type;
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}
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}

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

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import 'package:analyzer/dart/element/element.dart';
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import 'package:analyzer/dart/element/nullability_suffix.dart';
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import 'package:analyzer/dart/element/type.dart';
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import 'package:analyzer/dart/element/type_visitor.dart';
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import 'package:analyzer/src/dart/element/element.dart';
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import 'package:analyzer/src/dart/element/extensions.dart';
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import 'package:analyzer/src/dart/element/type.dart';
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import 'package:analyzer/src/dart/element/type_algebra.dart';
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import 'package:analyzer/src/dart/element/type_schema.dart';
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import 'package:analyzer/src/dart/element/type_visitor.dart';
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import 'package:analyzer/src/generated/utilities_dart.dart';
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import 'package:analyzer/src/summary2/function_type_builder.dart';
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import 'package:analyzer/src/summary2/named_type_builder.dart';
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import 'package:meta/meta.dart';
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/// Helper visitor that clones a type if a nested type is replaced, and
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/// otherwise returns `null`.
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class ReplacementVisitor implements DartTypeVisitor<DartType> {
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class ReplacementVisitor
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implements TypeVisitor<DartType>, InferenceTypeVisitor<DartType> {
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const ReplacementVisitor();
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void changeVariance() {}
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}
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@override
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DartType defaultDartType(DartType type) {
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DartType visitDartType(DartType type) {
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return null;
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}
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DartType visit(DartType type) {
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return DartTypeVisitor.visit(type, this);
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}
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@override
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DartType visitDynamicType(DynamicTypeImpl type) {
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DartType visitDynamicType(DynamicType type) {
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return null;
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}
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var typeParameter = node.typeFormals[i];
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var bound = typeParameter.bound;
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if (bound != null) {
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var newBound = visit(bound);
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var newBound = bound.accept(this);
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if (newBound != null) {
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newTypeParameters ??= node.typeFormals.toList(growable: false);
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newTypeParameters[i] = TypeParameterElementImpl.synthetic(
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DartType visitType(DartType type) {
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if (type == null) return null;
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var result = visit(type);
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var result = type.accept(this);
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if (substitution != null) {
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result = substitution.substituteType(result ?? type);
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}
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);
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}
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@override
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DartType visitFunctionTypeBuilder(FunctionTypeBuilder type) {
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throw UnimplementedError();
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}
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@override
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DartType visitInterfaceType(InterfaceType type) {
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var newNullability = visitNullability(type);
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List<DartType> newTypeArguments;
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for (var i = 0; i < type.typeArguments.length; i++) {
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var substitution = visit(type.typeArguments[i]);
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var substitution = type.typeArguments[i].accept(this);
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if (substitution != null) {
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newTypeArguments ??= type.typeArguments.toList(growable: false);
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newTypeArguments[i] = substitution;
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}
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@override
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DartType visitNamedTypeBuilder(NamedTypeBuilder type) {
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throw UnimplementedError();
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}
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@override
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DartType visitNeverType(NeverTypeImpl type) {
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DartType visitNeverType(NeverType type) {
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var newNullability = visitNullability(type);
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return createNeverType(
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var promotedBound = (type as TypeParameterTypeImpl).promotedBound;
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if (promotedBound != null) {
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var newPromotedBound = visit(promotedBound);
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var newPromotedBound = promotedBound.accept(this);
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return createPromotedTypeParameterType(
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type: type,
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newNullability: newNullability,

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

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@@ -10,6 +10,7 @@ import 'package:analyzer/dart/element/null_safety_understanding_flag.dart';
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import 'package:analyzer/dart/element/nullability_suffix.dart';
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import 'package:analyzer/dart/element/type.dart';
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import 'package:analyzer/dart/element/type_provider.dart';
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import 'package:analyzer/dart/element/type_visitor.dart';
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import 'package:analyzer/src/dart/analysis/session.dart';
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import 'package:analyzer/src/dart/element/display_string_builder.dart';
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import 'package:analyzer/src/dart/element/element.dart';
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@override
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bool operator ==(Object object) => identical(object, this);
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@override
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R accept<R>(TypeVisitor<R> visitor) {
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return visitor.visitDynamicType(this);
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}
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@override
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void appendTo(ElementDisplayStringBuilder builder) {
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builder.writeDynamicType();
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return false;
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}
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@override
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R accept<R>(TypeVisitor<R> visitor) {
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return visitor.visitFunctionType(this);
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}
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@override
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void appendTo(ElementDisplayStringBuilder builder) {
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builder.writeFunctionType(this);
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return false;
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}
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@override
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R accept<R>(TypeVisitor<R> visitor) {
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return visitor.visitInterfaceType(this);
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}
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@override
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void appendTo(ElementDisplayStringBuilder builder) {
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builder.writeInterfaceType(this);
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@override
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bool operator ==(Object object) => identical(object, this);
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@override
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R accept<R>(TypeVisitor<R> visitor) {
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return visitor.visitNeverType(this);
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}
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@override
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void appendTo(ElementDisplayStringBuilder builder) {
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builder.writeNeverType(this);
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return false;
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}
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@override
1975+
R accept<R>(TypeVisitor<R> visitor) {
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return visitor.visitTypeParameterType(this);
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}
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@override
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void appendTo(ElementDisplayStringBuilder builder) {
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builder.writeTypeParameterType(this);
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@override
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bool operator ==(Object object) => identical(object, this);
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@override
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R accept<R>(TypeVisitor<R> visitor) {
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return visitor.visitVoidType(this);
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}
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@override
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void appendTo(ElementDisplayStringBuilder builder) {
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builder.writeVoidType();

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