[cfe] Add LookupResult

This replaces the individual lookups of getables and setables in LookupScope and NameSpace with single lookup that returns a LookupResult holding both the getable and the setable. This prepares for having getter/setter pairs in the same SourcePropertyBuilder and avoids the need for AccessErrorBuilder for handling lookups of getters where only setters exist and vice versa.

Change-Id: I2b1e2477ed43506d9f94c48acd4b44277b490540
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/420080
Reviewed-by: Chloe Stefantsova <[email protected]>
Reviewed-by: Erik Ernst <[email protected]>
Commit-Queue: Johnni Winther <[email protected]>

Author: johnniwinther

pkg/front_end/lib/src/base/incremental_compiler.dart

@@ -694,9 +694,7 @@ class IncrementalCompiler implements IncrementalKernelGenerator {
       if (sourceBuilder == null) {
         sourceBuilder = sourceLibraryBuilder.exportNameSpace
             .lookupLocalMember(name, setter: false);
-        if (sourceBuilder is MemberBuilder &&
-            sourceBuilder.isField &&
-            sourceBuilder.isAssignable) {
+        if (sourceBuilder is MemberBuilder && sourceBuilder.hasSetter) {
           // Assignable fields can be lowered into a getter and setter.
           return;
         }

pkg/front_end/lib/src/base/local_scope.dart

@@ -2,9 +2,9 @@
 // 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 '../builder/builder.dart';
 import '../builder/declaration_builders.dart';
 import '../builder/variable_builder.dart';
+import 'lookup_result.dart';
 import 'scope.dart';
 
 abstract class LocalScope implements LookupScope {
@@ -16,12 +16,12 @@ abstract class LocalScope implements LookupScope {
 
   LocalScope createNestedFixedScope(
       {required String debugName,
-      required Map<String, Builder> local,
+      required Map<String, VariableBuilder> local,
       required ScopeKind kind});
 
-  Iterable<Builder> get localVariables;
+  Iterable<VariableBuilder> get localVariables;
 
-  Builder? lookupLocalVariable(String name);
+  VariableBuilder? lookupLocalVariable(String name);
 
   /// Declares that the meaning of [name] in this scope is [builder].
   ///
@@ -30,12 +30,6 @@ abstract class LocalScope implements LookupScope {
   /// [name] being used before its declared.
   List<int>? declare(String name, VariableBuilder builder);
 
-  @override
-  Builder? lookupGetable(String name, int charOffset, Uri fileUri);
-
-  @override
-  Builder? lookupSetable(String name, int charOffset, Uri uri);
-
   Map<String, List<int>>? get usedNames;
 }
 
@@ -49,53 +43,32 @@ abstract base class BaseLocalScope implements LocalScope {
   @override
   LocalScope createNestedFixedScope(
       {required String debugName,
-      required Map<String, Builder> local,
+      required Map<String, VariableBuilder> local,
       required ScopeKind kind}) {
     return new FixedLocalScope(
         kind: kind, parent: this, local: local, debugName: debugName);
   }
 }
 
-mixin LocalScopeMixin implements LookupScopeMixin, LocalScope {
+mixin LocalScopeMixin implements LocalScope {
   LookupScope? get _parent;
 
-  Map<String, Builder>? get _local;
-
-  @override
-  String get classNameOrDebugName;
+  Map<String, VariableBuilder>? get _local;
 
   @override
-  Iterable<Builder> get localVariables => _local?.values ?? const {};
+  Iterable<VariableBuilder> get localVariables => _local?.values ?? const [];
 
   @override
-  Builder? lookupGetable(String name, int charOffset, Uri fileUri) {
-    _recordUse(name, charOffset);
-    if (_local != null) {
-      Builder? builder = lookupGetableIn(name, charOffset, fileUri, _local!);
-      if (builder != null) {
-        return builder;
-      }
-    }
-    return _parent?.lookupGetable(name, charOffset, fileUri);
+  LookupResult? lookup(String name, int fileOffset, Uri fileUri) {
+    _recordUse(name, fileOffset);
+    return _local?[name] ?? _parent?.lookup(name, fileOffset, fileUri);
   }
 
   @override
-  Builder? lookupLocalVariable(String name) {
+  VariableBuilder? lookupLocalVariable(String name) {
     return _local?[name];
   }
 
-  @override
-  Builder? lookupSetable(String name, int charOffset, Uri fileUri) {
-    _recordUse(name, charOffset);
-    if (_local != null) {
-      Builder? builder = lookupSetableIn(name, charOffset, fileUri, _local);
-      if (builder != null) {
-        return builder;
-      }
-    }
-    return _parent?.lookupSetable(name, charOffset, fileUri);
-  }
-
   void _recordUse(String name, int charOffset) {}
 
   @override
@@ -106,13 +79,12 @@ mixin LocalScopeMixin implements LookupScopeMixin, LocalScope {
 }
 
 final class LocalScopeImpl extends BaseLocalScope
-    with LookupScopeMixin, LocalScopeMixin
+    with LocalScopeMixin
     implements LocalScope {
   @override
   final LocalScope? _parent;
 
-  @override
-  final String classNameOrDebugName;
+  final String _debugName;
 
   /// Names declared in this scope.
   @override
@@ -124,7 +96,7 @@ final class LocalScopeImpl extends BaseLocalScope
   @override
   final ScopeKind kind;
 
-  LocalScopeImpl(this._parent, this.kind, this.classNameOrDebugName);
+  LocalScopeImpl(this._parent, this.kind, this._debugName);
 
   @override
   List<int>? declare(String name, VariableBuilder builder) {
@@ -145,8 +117,7 @@ final class LocalScopeImpl extends BaseLocalScope
   }
 
   @override
-  String toString() =>
-      "$runtimeType(${kind}, $classNameOrDebugName, ${_local?.keys})";
+  String toString() => "$runtimeType(${kind}, $_debugName, ${_local?.keys})";
 }
 
 mixin ImmutableLocalScopeMixin implements LocalScope {
@@ -161,12 +132,12 @@ mixin ImmutableLocalScopeMixin implements LocalScope {
 }
 
 final class LocalTypeParameterScope extends BaseLocalScope
-    with LookupScopeMixin, ImmutableLocalScopeMixin, LocalScopeMixin {
-  @override
+    with ImmutableLocalScopeMixin {
   final LocalScope? _parent;
+
   @override
   final ScopeKind kind;
-  @override
+
   final Map<String, TypeParameterBuilder>? _local;
 
   final String _debugName;
@@ -181,61 +152,70 @@ final class LocalTypeParameterScope extends BaseLocalScope
         _debugName = debugName;
 
   @override
-  String get classNameOrDebugName => _debugName;
+  // Coverage-ignore(suite): Not run.
+  Iterable<VariableBuilder> get localVariables => const [];
 
   @override
-  String toString() =>
-      "$runtimeType(${kind}, $classNameOrDebugName, ${_local?.keys})";
+  LookupResult? lookup(String name, int fileOffset, Uri fileUri) {
+    return _local?[name] ?? _parent?.lookup(name, fileOffset, fileUri);
+  }
+
+  @override
+  // Coverage-ignore(suite): Not run.
+  VariableBuilder? lookupLocalVariable(String name) => null;
+
+  @override
+  // Coverage-ignore(suite): Not run.
+  void forEachExtension(void Function(ExtensionBuilder) f) {
+    _parent?.forEachExtension(f);
+  }
+
+  @override
+  String toString() => "$runtimeType(${kind}, $_debugName, ${_local?.keys})";
 }
 
 final class FixedLocalScope extends BaseLocalScope
-    with LookupScopeMixin, ImmutableLocalScopeMixin, LocalScopeMixin {
+    with ImmutableLocalScopeMixin, LocalScopeMixin {
   @override
   final LocalScope? _parent;
   @override
   final ScopeKind kind;
   @override
-  final Map<String, Builder>? _local;
+  final Map<String, VariableBuilder>? _local;
 
   final String _debugName;
 
   FixedLocalScope(
       {required this.kind,
       LocalScope? parent,
-      Map<String, Builder>? local,
+      Map<String, VariableBuilder>? local,
       required String debugName})
       : _parent = parent,
         _local = local,
         _debugName = debugName;
 
   @override
-  String get classNameOrDebugName => _debugName;
-
-  @override
-  String toString() =>
-      "$runtimeType(${kind}, $classNameOrDebugName, ${_local?.keys})";
+  String toString() => "$runtimeType(${kind}, $_debugName, ${_local?.keys})";
 }
 
 final class FormalParameterScope extends BaseLocalScope
-    with LookupScopeMixin, ImmutableLocalScopeMixin, LocalScopeMixin {
+    with ImmutableLocalScopeMixin, LocalScopeMixin {
   @override
   final LookupScope? _parent;
   @override
-  final Map<String, Builder>? _local;
+  final Map<String, VariableBuilder>? _local;
 
-  FormalParameterScope({LookupScope? parent, Map<String, Builder>? local})
+  FormalParameterScope(
+      {LookupScope? parent, Map<String, VariableBuilder>? local})
       : _parent = parent,
         _local = local;
 
   @override
   ScopeKind get kind => ScopeKind.formals;
 
-  @override
-  String get classNameOrDebugName => "formal parameter";
-
   @override
   String toString() =>
-      "$runtimeType(${kind}, $classNameOrDebugName, ${_local?.keys})";
+      "$runtimeType(${kind}, formal parameter, ${_local?.keys})";
 }
 
 final class EnclosingLocalScope extends BaseLocalScope
@@ -249,21 +229,16 @@ final class EnclosingLocalScope extends BaseLocalScope
 
   @override
   // Coverage-ignore(suite): Not run.
-  Iterable<Builder> get localVariables => const [];
+  Iterable<VariableBuilder> get localVariables => const [];
 
   @override
-  Builder? lookupGetable(String name, int charOffset, Uri fileUri) {
-    return _scope.lookupGetable(name, charOffset, fileUri);
+  LookupResult? lookup(String name, int fileOffset, Uri fileUri) {
+    return _scope.lookup(name, fileOffset, fileUri);
   }
 
   @override
   // Coverage-ignore(suite): Not run.
-  Builder? lookupLocalVariable(String name) => null;
-
-  @override
-  Builder? lookupSetable(String name, int charOffset, Uri uri) {
-    return _scope.lookupSetable(name, charOffset, uri);
-  }
+  VariableBuilder? lookupLocalVariable(String name) => null;
 
   @override
   // Coverage-ignore(suite): Not run.

pkg/front_end/lib/src/base/lookup_result.dart

@@ -0,0 +1,55 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// 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 '../builder/builder.dart';
+
+abstract class LookupResult {
+  /// The [Builder] used for reading this entity, if any.
+  Builder? get getable;
+
+  /// The [Builder] used for writing to this entity, if any.
+  Builder? get setable;
+
+  static LookupResult? fromBuilders(Builder? getable, Builder? setable) {
+    if (getable != null && setable != null) {
+      return new GetableSetableResult(getable, setable);
+    } else if (getable != null) {
+      return new GetableResult(getable);
+    } else if (setable != null) {
+      return new SetableResult(setable);
+    } else {
+      return null;
+    }
+  }
+}
+
+class GetableResult implements LookupResult {
+  @override
+  final Builder getable;
+
+  GetableResult(this.getable);
+
+  @override
+  Builder? get setable => null;
+}
+
+class SetableResult implements LookupResult {
+  @override
+  final Builder setable;
+
+  SetableResult(this.setable);
+
+  @override
+  Builder? get getable => null;
+}
+
+class GetableSetableResult implements LookupResult {
+  @override
+  final Builder getable;
+
+  @override
+  final Builder setable;
+
+  GetableSetableResult(this.getable, this.setable);
+}