[cfe] Implement static extension getters in the CFE

chloestefantsova · Commit Queue · commit adaa736bf3d5 · 2025-10-01T00:32:18.000-07:00
Part of #61484 Part of #61486 Change-Id: I4918027c164d590ff42ef36e7301a1939589040c Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/452145 Reviewed-by: Johnni Winther <johnniwinther@google.com> Commit-Queue: Chloe Stefantsova <cstefantsova@google.com>
diff --git a/pkg/front_end/lib/src/base/scope.dart b/pkg/front_end/lib/src/base/scope.dart
@@ -121,11 +121,13 @@ enum ScopeKind {
   import,
 }
 
-abstract class LookupScope {
+abstract class ExtensionScope {
+  void forEachExtension(void Function(ExtensionBuilder) f);
+}
+
+abstract class LookupScope implements ExtensionScope {
   ScopeKind get kind;
   LookupResult? lookup(String name);
-  // TODO(johnniwinther): Should this be moved to an outer scope interface?
-  void forEachExtension(void Function(ExtensionBuilder) f);
 }
 
 /// A [LookupScope] based directly on a [NameSpace].
diff --git a/pkg/front_end/lib/src/kernel/body_builder.dart b/pkg/front_end/lib/src/kernel/body_builder.dart
@@ -349,6 +349,9 @@ class BodyBuilderImpl extends StackListenerImpl
   /// Index for building unique lowered names for wildcard variables.
   int wildcardVariableIndex = 0;
 
+  @override
+  ExtensionScope extensionScope;
+
   BodyBuilderImpl({
     required this.libraryBuilder,
     required BodyBuilderContext context,
@@ -362,6 +365,7 @@ class BodyBuilderImpl extends StackListenerImpl
     required this.assignedVariables,
     required this.typeEnvironment,
     required ConstantContext constantContext,
+    required this.extensionScope,
   }) : _context = context,
        forest = const Forest(),
        enableNative = libraryBuilder.loader.target.backendTarget.enableNative(
diff --git a/pkg/front_end/lib/src/kernel/expression_generator.dart b/pkg/front_end/lib/src/kernel/expression_generator.dart
@@ -4461,12 +4461,38 @@ class TypeUseGenerator extends AbstractReadOnlyAccessGenerator {
               return tearOffExpression;
             }
           }
-          generator = new UnresolvedNameGenerator(
-            _helper,
-            send.token,
-            name,
-            unresolvedReadKind: UnresolvedKind.Member,
-          );
+
+          MemberBuilder? extensionMemberBuilder;
+
+          if (_helper.libraryFeatures.staticExtensions.isEnabled) {
+            _helper.extensionScope.forEachExtension((
+              ExtensionBuilder extensionBuilder,
+            ) {
+              if (extensionBuilder.onType.declaration == declaration) {
+                extensionMemberBuilder = extensionBuilder
+                    .lookupLocalMemberByName(name, setter: false);
+              }
+            });
+          }
+
+          if (extensionMemberBuilder != null) {
+            generator = new StaticAccessGenerator.fromBuilder(
+              _helper,
+              name,
+              send.token,
+              extensionMemberBuilder,
+              null,
+              typeOffset: fileOffset,
+              isNullAware: isNullAware,
+            );
+          } else {
+            generator = new UnresolvedNameGenerator(
+              _helper,
+              send.token,
+              name,
+              unresolvedReadKind: UnresolvedKind.Member,
+            );
+          }
         } else {
           return _helper.resolveAndBuildConstructorInvocation(
             declarationBuilder,
diff --git a/pkg/front_end/lib/src/kernel/expression_generator_helper.dart b/pkg/front_end/lib/src/kernel/expression_generator_helper.dart
@@ -58,6 +58,8 @@ abstract class ExpressionGeneratorHelper {
 
   CompilerContext get compilerContext;
 
+  ExtensionScope get extensionScope;
+
   InvalidExpression buildProblem({
     required Message message,
     required Uri fileUri,
diff --git a/pkg/front_end/lib/src/kernel/resolver.dart b/pkg/front_end/lib/src/kernel/resolver.dart
@@ -944,6 +944,7 @@ class Resolver {
       libraryBuilder: context.libraryBuilder,
       context: bodyBuilderContext,
       enclosingScope: new EnclosingLocalScope(scope),
+      extensionScope: context.typeInferrer.extensionScope,
       formalParameterScope: formalParameterScope,
       hierarchy: _classHierarchy,
       coreTypes: _coreTypes,
diff --git a/pkg/front_end/lib/src/type_inference/inference_visitor_base.dart b/pkg/front_end/lib/src/type_inference/inference_visitor_base.dart
@@ -190,7 +190,7 @@ abstract class InferenceVisitorBase implements InferenceVisitor {
 
   ProblemReportingHelper get problemReportingHelper => libraryBuilder.loader;
 
-  LookupScope get extensionScope => _inferrer.extensionScope;
+  ExtensionScope get extensionScope => _inferrer.extensionScope;
 
   bool get isInferenceUpdate1Enabled =>
       libraryBuilder.isInferenceUpdate1Enabled;
diff --git a/pkg/front_end/lib/src/type_inference/type_inferrer.dart b/pkg/front_end/lib/src/type_inference/type_inferrer.dart
@@ -33,6 +33,9 @@ abstract class TypeInferrer {
   /// Gets the [TypeSchemaEnvironment] being used for type inference.
   TypeSchemaEnvironment get typeSchemaEnvironment;
 
+  /// Gets the [ExtensionScope] being used for type inference.
+  ExtensionScope get extensionScope;
+
   /// Returns the [FlowAnalysis] used during inference.
   FlowAnalysis<
     TreeNode,
@@ -134,7 +137,8 @@ class TypeInferrerImpl implements TypeInferrer {
 
   final SourceLibraryBuilder libraryBuilder;
 
-  final LookupScope extensionScope;
+  @override
+  final ExtensionScope extensionScope;
 
   late final StaticTypeContext staticTypeContext =
       new StaticTypeContextImpl.direct(
@@ -381,11 +385,14 @@ class TypeInferrerImplBenchmarked implements TypeInferrer {
   final TypeInferrerImpl impl;
   final Benchmarker benchmarker;
 
+  @override
+  final ExtensionScope extensionScope;
+
   TypeInferrerImplBenchmarked(
     TypeInferenceEngine engine,
     InterfaceType? thisType,
     SourceLibraryBuilder libraryBuilder,
-    LookupScope extensionScope,
+    this.extensionScope,
     AssignedVariables<TreeNode, VariableDeclaration> assignedVariables,
     InferenceDataForTesting? dataForTesting,
     this.benchmarker,
diff --git a/pkg/front_end/test/compiler_test_helper.dart b/pkg/front_end/test/compiler_test_helper.dart
@@ -301,6 +301,7 @@ class BodyBuilderTest extends BodyBuilderImpl {
          libraryBuilder: libraryBuilder,
          context: context,
          enclosingScope: new EnclosingLocalScope(enclosingScope),
+         extensionScope: enclosingScope,
          formalParameterScope: formalParameterScope,
          hierarchy: hierarchy,
          coreTypes: coreTypes,
diff --git a/pkg/front_end/test/generator_to_string_test.dart b/pkg/front_end/test/generator_to_string_test.dart
@@ -187,14 +187,16 @@ Future<void> main() async {
       extensionScope: compilationUnit.compilationUnitScope,
     );
 
+    LocalScope lookupScope = new FixedLocalScope(
+      kind: ScopeKind.library,
+      debugName: "dummy",
+    );
     ExpressionGeneratorHelper helper = new BodyBuilderImpl(
       libraryBuilder: libraryBuilder,
       context: new LibraryBodyBuilderContext(libraryBuilder),
       uri: uri,
-      enclosingScope: new FixedLocalScope(
-        kind: ScopeKind.library,
-        debugName: "dummy",
-      ),
+      enclosingScope: lookupScope,
+      extensionScope: lookupScope,
       coreTypes: coreTypes,
       hierarchy: hierarchy,
       assignedVariables: typeInferrer.assignedVariables,
diff --git a/pkg/front_end/testcases/static_extensions/folder.options b/pkg/front_end/testcases/static_extensions/folder.options
@@ -0,0 +1 @@
+--enable-experiment=static-extensions
diff --git a/pkg/front_end/testcases/static_extensions/simple_positive.dart b/pkg/front_end/testcases/static_extensions/simple_positive.dart
@@ -0,0 +1,23 @@
+// 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.
+
+class A {
+  static String get foo => "A.foo";
+}
+
+extension E on A {
+  static String get foo => "E.foo";
+  static String get bar => "E.bar";
+}
+
+main() {
+  expectEqual(A.foo, "A.foo");
+  expectEqual(A.bar, "E.bar");
+}
+
+expectEqual(a, b) {
+  if (a != b) {
+    throw "Expected the values to be equal.";
+  }
+}
diff --git a/pkg/front_end/testcases/static_extensions/simple_positive.dart.strong.expect b/pkg/front_end/testcases/static_extensions/simple_positive.dart.strong.expect
@@ -0,0 +1,28 @@
+library;
+import self as self;
+import "dart:core" as core;
+
+class A extends core::Object {
+  synthetic constructor •() → self::A
+    : super core::Object::•()
+    ;
+  static get foo() → core::String
+    return "A.foo";
+}
+extension E on self::A {
+  static get foo = get self::E|foo;
+  static get bar = get self::E|bar;
+}
+static extension-member get E|foo() → core::String
+  return "E.foo";
+static extension-member get E|bar() → core::String
+  return "E.bar";
+static method main() → dynamic {
+  self::expectEqual(self::A::foo, "A.foo");
+  self::expectEqual(self::E|bar, "E.bar");
+}
+static method expectEqual(dynamic a, dynamic b) → dynamic {
+  if(!(a =={core::Object::==}{(core::Object) → core::bool} b)) {
+    throw "Expected the values to be equal.";
+  }
+}
diff --git a/pkg/front_end/testcases/static_extensions/simple_positive.dart.strong.modular.expect b/pkg/front_end/testcases/static_extensions/simple_positive.dart.strong.modular.expect
@@ -0,0 +1,28 @@
+library;
+import self as self;
+import "dart:core" as core;
+
+class A extends core::Object {
+  synthetic constructor •() → self::A
+    : super core::Object::•()
+    ;
+  static get foo() → core::String
+    return "A.foo";
+}
+extension E on self::A {
+  static get foo = get self::E|foo;
+  static get bar = get self::E|bar;
+}
+static extension-member get E|foo() → core::String
+  return "E.foo";
+static extension-member get E|bar() → core::String
+  return "E.bar";
+static method main() → dynamic {
+  self::expectEqual(self::A::foo, "A.foo");
+  self::expectEqual(self::E|bar, "E.bar");
+}
+static method expectEqual(dynamic a, dynamic b) → dynamic {
+  if(!(a =={core::Object::==}{(core::Object) → core::bool} b)) {
+    throw "Expected the values to be equal.";
+  }
+}
diff --git a/pkg/front_end/testcases/static_extensions/simple_positive.dart.strong.outline.expect b/pkg/front_end/testcases/static_extensions/simple_positive.dart.strong.outline.expect
@@ -0,0 +1,22 @@
+library;
+import self as self;
+import "dart:core" as core;
+
+class A extends core::Object {
+  synthetic constructor •() → self::A
+    ;
+  static get foo() → core::String
+    ;
+}
+extension E on self::A {
+  static get foo = get self::E|foo;
+  static get bar = get self::E|bar;
+}
+static extension-member get E|foo() → core::String
+  ;
+static extension-member get E|bar() → core::String
+  ;
+static method main() → dynamic
+  ;
+static method expectEqual(dynamic a, dynamic b) → dynamic
+  ;
diff --git a/pkg/front_end/testcases/static_extensions/simple_positive.dart.strong.transformed.expect b/pkg/front_end/testcases/static_extensions/simple_positive.dart.strong.transformed.expect
@@ -0,0 +1,28 @@
+library;
+import self as self;
+import "dart:core" as core;
+
+class A extends core::Object {
+  synthetic constructor •() → self::A
+    : super core::Object::•()
+    ;
+  static get foo() → core::String
+    return "A.foo";
+}
+extension E on self::A {
+  static get foo = get self::E|foo;
+  static get bar = get self::E|bar;
+}
+static extension-member get E|foo() → core::String
+  return "E.foo";
+static extension-member get E|bar() → core::String
+  return "E.bar";
+static method main() → dynamic {
+  self::expectEqual(self::A::foo, "A.foo");
+  self::expectEqual(self::E|bar, "E.bar");
+}
+static method expectEqual(dynamic a, dynamic b) → dynamic {
+  if(!(a =={core::Object::==}{(core::Object) → core::bool} b)) {
+    throw "Expected the values to be equal.";
+  }
+}
diff --git a/pkg/front_end/testcases/static_extensions/simple_positive.dart.textual_outline.expect b/pkg/front_end/testcases/static_extensions/simple_positive.dart.textual_outline.expect
@@ -0,0 +1,12 @@
+class A {
+  static String get foo => "A.foo";
+}
+
+extension E on A {
+  static String get foo => "E.foo";
+  static String get bar => "E.bar";
+}
+
+main() {}
+
+expectEqual(a, b) {}
diff --git a/pkg/front_end/testcases/static_extensions/simple_positive.dart.textual_outline_modelled.expect b/pkg/front_end/testcases/static_extensions/simple_positive.dart.textual_outline_modelled.expect
@@ -0,0 +1,12 @@
+class A {
+  static String get foo => "A.foo";
+}
+
+expectEqual(a, b) {}
+
+extension E on A {
+  static String get bar => "E.bar";
+  static String get foo => "E.foo";
+}
+
+main() {}
