[cfe] Introduce NameSpace

This adds a NameSpace interface to Scope and uses it for access to
local members. The NameSpace represents entities declared with a library
or class/extension (type) declaration and is to be used for creating
a Scope instead of being the scope itself. As such it is added to
LibraryBuilder and IDeclarationBuilder and used in place of the `scope`
property for accessing these entities.

Change-Id: Id9b03bc8e820ad8f6d185cc95d695ac4a5e59f8f
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/376622
Commit-Queue: Johnni Winther <johnniwinther@google.com>
Reviewed-by: Chloe Stefantsova <cstefantsova@google.com>

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

@@ -640,7 +640,7 @@ class IncrementalCompiler implements IncrementalKernelGenerator {
 
             // Clear cached calculations that points (potential) to now replaced
             // things.
-            for (Builder builder in builder.scope.localMembers) {
+            for (Builder builder in builder.nameSpace.localMembers) {
               if (builder is DillClassBuilder) {
                 builder.clearCachedValues();
               }
@@ -1042,7 +1042,7 @@ class IncrementalCompiler implements IncrementalKernelGenerator {
         if (builder.isBuiltAndMarked) {
           // Clear cached calculations in classes which upon calculation can
           // mark things as needed.
-          for (Builder builder in builder.scope.localMembers) {
+          for (Builder builder in builder.nameSpace.localMembers) {
             if (builder is DillClassBuilder) {
               builder.clearCachedValues();
             }
@@ -1886,8 +1886,8 @@ class IncrementalCompiler implements IncrementalKernelGenerator {
 
       Class? cls;
       if (className != null) {
-        Builder? scopeMember =
-            libraryBuilder.scope.lookupLocalMember(className, setter: false);
+        Builder? scopeMember = libraryBuilder.nameSpace
+            .lookupLocalMember(className, setter: false);
         if (scopeMember is ClassBuilder) {
           cls = scopeMember.cls;
         } else {
@@ -1902,8 +1902,8 @@ class IncrementalCompiler implements IncrementalKernelGenerator {
         if (indexOfDot >= 0) {
           String beforeDot = methodName.substring(0, indexOfDot);
           String afterDot = methodName.substring(indexOfDot + 1);
-          Builder? builder =
-              libraryBuilder.scope.lookupLocalMember(beforeDot, setter: false);
+          Builder? builder = libraryBuilder.nameSpace
+              .lookupLocalMember(beforeDot, setter: false);
           extensionName = beforeDot;
           if (builder is ExtensionBuilder) {
             extension = builder.extension;
@@ -1983,14 +1983,14 @@ class IncrementalCompiler implements IncrementalKernelGenerator {
         isPatch: false,
       );
       debugLibrary.compilationUnit.createLibrary();
-      libraryBuilder.scope.forEachLocalMember((name, member) {
-        debugLibrary.scope.addLocalMember(name, member, setter: false);
+      libraryBuilder.nameSpace.forEachLocalMember((name, member) {
+        debugLibrary.nameSpace.addLocalMember(name, member, setter: false);
       });
-      libraryBuilder.scope.forEachLocalSetter((name, member) {
-        debugLibrary.scope.addLocalMember(name, member, setter: true);
+      libraryBuilder.nameSpace.forEachLocalSetter((name, member) {
+        debugLibrary.nameSpace.addLocalMember(name, member, setter: true);
       });
-      libraryBuilder.scope.forEachLocalExtension((member) {
-        debugLibrary.scope.addExtension(member);
+      libraryBuilder.nameSpace.forEachLocalExtension((member) {
+        debugLibrary.nameSpace.addExtension(member);
       });
       _ticker.logMs("Created debug library");
 

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

@@ -2,6 +2,8 @@
 // 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.
 
+// ignore_for_file: annotate_overrides
+
 library fasta.scope;
 
 import 'package:kernel/ast.dart';
@@ -178,7 +180,68 @@ class MutableScope {
   String toString() => "Scope(${kind}, $classNameOrDebugName, ${_local?.keys})";
 }
 
-class Scope extends MutableScope implements ParentScope, LookupScope {
+abstract class NameSpace {
+  void addLocalMember(String name, Builder member, {required bool setter});
+
+  Builder? lookupLocalMember(String name, {required bool setter});
+
+  void forEachLocalMember(void Function(String name, Builder member) f);
+
+  void forEachLocalSetter(void Function(String name, MemberBuilder member) f);
+
+  void forEachLocalExtension(void Function(ExtensionBuilder member) f);
+
+  Iterable<Builder> get localMembers;
+
+  /// Returns an iterator of all members and setters mapped in this scope,
+  /// including duplicate members mapped to the same name.
+  ///
+  /// The iterator does _not_ include the members and setters mapped in the
+  /// [parent] scope.
+  Iterator<Builder> get unfilteredIterator;
+
+  /// Returns an iterator of all members and setters mapped in this scope,
+  /// including duplicate members mapped to the same name.
+  ///
+  /// The iterator does _not_ include the members and setters mapped in the
+  /// [parent] scope.
+  ///
+  /// Compared to [unfilteredIterator] this iterator also gives access to the
+  /// name that the builders are mapped to.
+  NameIterator get unfilteredNameIterator;
+
+  /// Returns a filtered iterator of members and setters mapped in this scope.
+  ///
+  /// Only members of type [T] are included. If [parent] is provided, on members
+  /// declared in [parent] are included. If [includeDuplicates] is `true`, all
+  /// duplicates of the same name are included, otherwise, only the first
+  /// declared member is included. If [includeAugmentations] is `true`, both
+  /// original and augmenting/patching members are included, otherwise, only
+  /// original members are included.
+  Iterator<T> filteredIterator<T extends Builder>(
+      {Builder? parent,
+      required bool includeDuplicates,
+      required bool includeAugmentations});
+
+  /// Returns a filtered iterator of members and setters mapped in this scope.
+  ///
+  /// Only members of type [T] are included. If [parent] is provided, on members
+  /// declared in [parent] are included. If [includeDuplicates] is `true`, all
+  /// duplicates of the same name are included, otherwise, only the first
+  /// declared member is included. If [includeAugmentations] is `true`, both
+  /// original and augmenting/patching members are included, otherwise, only
+  /// original members are included.
+  ///
+  /// Compared to [filteredIterator] this iterator also gives access to the
+  /// name that the builders are mapped to.
+  NameIterator<T> filteredNameIterator<T extends Builder>(
+      {Builder? parent,
+      required bool includeDuplicates,
+      required bool includeAugmentations});
+}
+
+class Scope extends MutableScope
+    implements ParentScope, LookupScope, NameSpace {
   /// Indicates whether an attempt to declare new names in this scope should
   /// succeed.
   final bool isModifiable;

pkg/front_end/lib/src/builder/builder_mixins.dart

@@ -58,7 +58,7 @@ mixin DeclarationBuilderMixin implements IDeclarationBuilder {
   }
 
   void forEach(void f(String name, Builder builder)) {
-    scope
+    nameSpace
         .filteredNameIterator(
             includeDuplicates: false, includeAugmentations: false)
         .forEach(f);
@@ -72,7 +72,7 @@ mixin DeclarationBuilderMixin implements IDeclarationBuilder {
       {bool setter = false, bool required = false}) {
     // TODO(johnniwinther): Support augmented on extensions/extension type
     //  declarations.
-    Builder? builder = scope.lookupLocalMember(name, setter: setter);
+    Builder? builder = nameSpace.lookupLocalMember(name, setter: setter);
     if (required && builder == null) {
       internalProblem(
           templateInternalProblemNotFoundIn.withArguments(

pkg/front_end/lib/src/builder/class_builder.dart

@@ -177,16 +177,9 @@ abstract class ClassBuilderImpl extends DeclarationBuilderImpl
   InterfaceType? _nonNullableRawType;
   InterfaceType? _thisType;
 
-  ClassBuilderImpl(
-      List<MetadataBuilder>? metadata,
-      int modifiers,
-      String name,
-      Scope scope,
-      ConstructorScope constructorScope,
-      LibraryBuilder parent,
-      int charOffset)
-      : super(metadata, modifiers, name, parent, charOffset, scope,
-            constructorScope);
+  ClassBuilderImpl(List<MetadataBuilder>? metadata, int modifiers, String name,
+      LibraryBuilder parent, int charOffset)
+      : super(metadata, modifiers, name, parent, charOffset);
 
   @override
   String get debugName => "ClassBuilder";
@@ -236,10 +229,10 @@ abstract class ClassBuilderImpl extends DeclarationBuilderImpl
   @override
   Builder? lookupLocalMember(String name,
       {bool setter = false, bool required = false}) {
-    Builder? builder = scope.lookupLocalMember(name, setter: setter);
+    Builder? builder = nameSpace.lookupLocalMember(name, setter: setter);
     if (builder == null && isAugmenting) {
       // Coverage-ignore-block(suite): Not run.
-      builder = origin.scope.lookupLocalMember(name, setter: setter);
+      builder = origin.nameSpace.lookupLocalMember(name, setter: setter);
     }
     if (required && builder == null) {
       internalProblem(

pkg/front_end/lib/src/builder/constructor_reference_builder.dart

@@ -34,7 +34,7 @@ class ConstructorReferenceBuilder {
         "${suffix == null ? '' : '.$suffix'}";
   }
 
-  void resolveIn(Scope scope, LibraryBuilder accessingLibrary) {
+  void resolveIn(LookupScope scope, LibraryBuilder accessingLibrary) {
     Builder? declaration;
     String? qualifier = typeName.qualifier;
     if (qualifier != null) {

pkg/front_end/lib/src/builder/declaration_builder.dart

@@ -7,6 +7,8 @@ part of 'declaration_builders.dart';
 abstract class IDeclarationBuilder implements ITypeDeclarationBuilder {
   Scope get scope;
 
+  NameSpace get nameSpace;
+
   LibraryBuilder get libraryBuilder;
 
   @override
@@ -48,23 +50,11 @@ abstract class IDeclarationBuilder implements ITypeDeclarationBuilder {
 
 abstract class DeclarationBuilderImpl extends TypeDeclarationBuilderImpl
     implements IDeclarationBuilder {
-  @override
-  final Scope scope;
-
-  @override
-  final ConstructorScope constructorScope;
-
   @override
   final Uri fileUri;
 
-  DeclarationBuilderImpl(
-      List<MetadataBuilder>? metadata,
-      int modifiers,
-      String name,
-      LibraryBuilder parent,
-      int charOffset,
-      this.scope,
-      this.constructorScope)
+  DeclarationBuilderImpl(List<MetadataBuilder>? metadata, int modifiers,
+      String name, LibraryBuilder parent, int charOffset)
       : fileUri = parent.fileUri,
         super(metadata, modifiers, name, parent, charOffset);
 

pkg/front_end/lib/src/builder/extension_builder.dart

@@ -34,9 +34,8 @@ abstract class ExtensionBuilderImpl extends DeclarationBuilderImpl
     with DeclarationBuilderMixin
     implements ExtensionBuilder {
   ExtensionBuilderImpl(List<MetadataBuilder>? metadata, int modifiers,
-      String name, LibraryBuilder parent, int charOffset, Scope scope)
-      : super(metadata, modifiers, name, parent, charOffset, scope,
-            new ConstructorScope(name, const {}));
+      String name, LibraryBuilder parent, int charOffset)
+      : super(metadata, modifiers, name, parent, charOffset);
 
   @override
   DartType buildAliasedTypeWithBuiltArguments(

pkg/front_end/lib/src/builder/extension_type_declaration_builder.dart

@@ -35,16 +35,9 @@ abstract class ExtensionTypeDeclarationBuilderImpl
     extends DeclarationBuilderImpl
     with DeclarationBuilderMixin
     implements ExtensionTypeDeclarationBuilder {
-  ExtensionTypeDeclarationBuilderImpl(
-      List<MetadataBuilder>? metadata,
-      int modifiers,
-      String name,
-      LibraryBuilder parent,
-      int charOffset,
-      Scope scope,
-      ConstructorScope constructorScope)
-      : super(metadata, modifiers, name, parent, charOffset, scope,
-            constructorScope);
+  ExtensionTypeDeclarationBuilderImpl(List<MetadataBuilder>? metadata,
+      int modifiers, String name, LibraryBuilder parent, int charOffset)
+      : super(metadata, modifiers, name, parent, charOffset);
 
   @override
   DartType buildAliasedTypeWithBuiltArguments(

pkg/front_end/lib/src/builder/library_builder.dart

@@ -260,6 +260,8 @@ abstract class SourceCompilationUnit implements CompilationUnit {
 abstract class LibraryBuilder implements Builder, ProblemReporting {
   Scope get scope;
 
+  NameSpace get nameSpace;
+
   Scope get exportScope;
 
   List<Export> get exporters;
@@ -420,19 +422,19 @@ abstract class LibraryBuilderImpl extends ModifierBuilderImpl
 
   @override
   Iterator<Builder> get localMembersIterator {
-    return scope.filteredIterator(
+    return nameSpace.filteredIterator(
         parent: this, includeDuplicates: true, includeAugmentations: true);
   }
 
   @override
   Iterator<T> localMembersIteratorOfType<T extends Builder>() {
-    return scope.filteredIterator<T>(
+    return nameSpace.filteredIterator<T>(
         parent: this, includeDuplicates: true, includeAugmentations: true);
   }
 
   @override
   NameIterator<Builder> get localMembersNameIterator {
-    return scope.filteredNameIterator(
+    return nameSpace.filteredNameIterator(
         parent: this, includeDuplicates: true, includeAugmentations: true);
   }
 
@@ -523,7 +525,7 @@ abstract class LibraryBuilderImpl extends ModifierBuilderImpl
 
   @override
   Builder? lookupLocalMember(String name, {bool required = false}) {
-    Builder? builder = scope.lookupLocalMember(name, setter: false);
+    Builder? builder = nameSpace.lookupLocalMember(name, setter: false);
     if (required && builder == null) {
       internalProblem(
           templateInternalProblemNotFoundIn.withArguments(

pkg/front_end/lib/src/builder/named_type_builder.dart

@@ -192,7 +192,7 @@ abstract class NamedTypeBuilderImpl extends NamedTypeBuilder {
   }
 
   @override
-  void resolveIn(Scope scope, int charOffset, Uri fileUri,
+  void resolveIn(LookupScope scope, int charOffset, Uri fileUri,
       ProblemReporting problemReporting) {
     if (_declaration != null) return;
     Builder? member;

pkg/front_end/lib/src/builder/type_builder.dart

@@ -491,7 +491,7 @@ abstract class NamedTypeBuilder extends TypeBuilder {
   @override
   TypeName get typeName;
 
-  void resolveIn(Scope scope, int charOffset, Uri fileUri,
+  void resolveIn(LookupScope scope, int charOffset, Uri fileUri,
       ProblemReporting problemReporting);
   void bind(
       ProblemReporting problemReporting, TypeDeclarationBuilder declaration);