[cfe] Support default values in primary constructor parameters

This adds support for default values in primary constructor parameters.

The code handling default values is refactored to ensure consistent handling of the default values, since these need to be part of the outline in some but not all cases.

The default values not included in the outline are computed during the full compilation.

Part of #61700

Change-Id: Ief1a516e06d1321a5b0c94b58bf33ec3837befa4
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/459422
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>

Author: johnniwinther

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

@@ -27,11 +27,10 @@ import '../source/fragment_factory.dart';
 import '../source/source_constructor_builder.dart';
 import '../source/source_factory_builder.dart';
 import '../source/source_library_builder.dart';
+import '../source/source_member_builder.dart';
 import '../source/source_property_builder.dart';
 import 'builder.dart';
-import 'constructor_builder.dart';
 import 'declaration_builders.dart';
-import 'member_builder.dart';
 import 'omitted_type_builder.dart';
 import 'property_builder.dart';
 import 'type_builder.dart';
@@ -87,7 +86,7 @@ class FormalParameterBuilder extends NamedBuilderImpl
   ///
   /// This is stored until outlines have been built through
   /// [buildOutlineExpressions].
-  Token? initializerToken;
+  Token? _initializerToken;
 
   bool initializerWasInferred = false;
 
@@ -111,9 +110,11 @@ class FormalParameterBuilder extends NamedBuilderImpl
     this.fileOffset, {
     required this.fileUri,
     this.isExtensionThis = false,
+    Token? initializerToken,
     required this.hasImmediatelyDeclaredInitializer,
     this.isWildcard = false,
-  }) : this.hasDeclaredInitializer = hasImmediatelyDeclaredInitializer {
+  }) : this.hasDeclaredInitializer = hasImmediatelyDeclaredInitializer,
+       this._initializerToken = initializerToken {
     type.registerInferredTypeListener(this);
   }
 
@@ -207,6 +208,7 @@ class FormalParameterBuilder extends NamedBuilderImpl
       fileOffset,
       fileUri: fileUri,
       isExtensionThis: isExtensionThis,
+      initializerToken: _takeInitializerToken(),
       hasImmediatelyDeclaredInitializer: hasImmediatelyDeclaredInitializer,
     )..variable = variable;
   }
@@ -259,8 +261,8 @@ class FormalParameterBuilder extends NamedBuilderImpl
     }
   }
 
-  static bool needsDefaultValuesBuiltAsOutlineExpressions(
-    MemberBuilder memberBuilder,
+  static bool _needsDefaultValuesBuiltAsOutlineExpressions(
+    SourceMemberBuilder memberBuilder,
   ) {
     // For modular compilation we need to include default values for optional
     // and named parameters in several cases:
@@ -271,26 +273,41 @@ class FormalParameterBuilder extends NamedBuilderImpl
     //   in mixin applications, and
     // * for factories, to uphold the invariant that optional parameters always
     //   have default values, even during modular compilation.
-    if (memberBuilder is ConstructorBuilder) {
+    if (memberBuilder is SourceConstructorBuilder) {
       return true;
     } else if (memberBuilder is SourceFactoryBuilder) {
       return true;
     } else {
-      // Coverage-ignore-block(suite): Not run.
       return memberBuilder.isClassInstanceMember;
     }
   }
 
+  /// Returns the [_initializerToken] field and clears it.
+  ///
+  /// This is used to transfer ownership of the token to the receiver. Tokens
+  /// need to be cleared during the outline phase to avoid holding the token
+  /// stream in memory.
+  Token? _takeInitializerToken() {
+    Token? initializerToken = _initializerToken;
+    _initializerToken = null;
+    return initializerToken;
+  }
+
   /// Builds the default value from this [initializerToken] if this is a
   /// formal parameter on a const constructor or instance method.
-  void buildOutlineExpressions(
-    SourceLibraryBuilder libraryBuilder,
-    DeclarationBuilder? declarationBuilder, {
+  void buildOutlineExpressions({
+    required SourceLibraryBuilder libraryBuilder,
+    required DeclarationBuilder? declarationBuilder,
+    required SourceMemberBuilder memberBuilder,
     required ExtensionScope extensionScope,
     required LookupScope scope,
-    required bool buildDefaultValue,
   }) {
-    if (buildDefaultValue) {
+    // For const constructors we need to include default parameter values
+    // into the outline. For all other formals we need to call
+    // buildOutlineExpressions to clear initializerToken to prevent
+    // consuming too much memory.
+    Token? initializerToken = _takeInitializerToken();
+    if (_needsDefaultValuesBuiltAsOutlineExpressions(memberBuilder)) {
       if (initializerToken != null) {
         BodyBuilderContext bodyBuilderContext = new ParameterBodyBuilderContext(
           libraryBuilder,
@@ -305,7 +322,7 @@ class FormalParameterBuilder extends NamedBuilderImpl
           extensionScope: extensionScope,
           scope: scope,
           fileUri: fileUri,
-          initializerToken: initializerToken!,
+          initializerToken: initializerToken,
           declaredType: variable!.type,
           hasDeclaredInitializer: hasDeclaredInitializer,
         );
@@ -319,7 +336,6 @@ class FormalParameterBuilder extends NamedBuilderImpl
         variable!.initializer = new NullLiteral()..parent = variable;
       }
     }
-    initializerToken = null;
   }
 
   @override

pkg/front_end/lib/src/fragment/constructor/declaration.dart

@@ -614,6 +614,7 @@ mixin _ConstructorDeclarationMixin
   void _buildTypeParametersAndFormalsForOutlineExpressions({
     required SourceLibraryBuilder libraryBuilder,
     required DeclarationBuilder declarationBuilder,
+    required SourceConstructorBuilder constructorBuilder,
     required BodyBuilderContext bodyBuilderContext,
     required ClassHierarchy classHierarchy,
   });
@@ -644,6 +645,7 @@ mixin _ConstructorDeclarationMixin
     _buildTypeParametersAndFormalsForOutlineExpressions(
       libraryBuilder: libraryBuilder,
       declarationBuilder: declarationBuilder,
+      constructorBuilder: constructorBuilder,
       bodyBuilderContext: bodyBuilderContext,
       classHierarchy: classHierarchy,
     );
@@ -795,6 +797,7 @@ mixin _RegularConstructorDeclarationMixin
   void _buildTypeParametersAndFormals({
     required SourceLibraryBuilder libraryBuilder,
     required DeclarationBuilder declarationBuilder,
+    required SourceConstructorBuilder constructorBuilder,
     required BodyBuilderContext bodyBuilderContext,
     required ClassHierarchy classHierarchy,
     required ExtensionScope extensionScope,
@@ -811,17 +814,13 @@ mixin _RegularConstructorDeclarationMixin
     }
 
     if (formals != null) {
-      // For const constructors we need to include default parameter values
-      // into the outline. For all other formals we need to call
-      // buildOutlineExpressions to clear initializerToken to prevent
-      // consuming too much memory.
       for (FormalParameterBuilder formal in formals!) {
         formal.buildOutlineExpressions(
-          libraryBuilder,
-          declarationBuilder,
+          libraryBuilder: libraryBuilder,
+          declarationBuilder: declarationBuilder,
+          memberBuilder: constructorBuilder,
           extensionScope: extensionScope,
           scope: typeParameterScope,
-          buildDefaultValue: true,
         );
       }
     }
@@ -1008,12 +1007,14 @@ class RegularConstructorDeclaration
   void _buildTypeParametersAndFormalsForOutlineExpressions({
     required SourceLibraryBuilder libraryBuilder,
     required DeclarationBuilder declarationBuilder,
+    required SourceConstructorBuilder constructorBuilder,
     required BodyBuilderContext bodyBuilderContext,
     required ClassHierarchy classHierarchy,
   }) {
     _buildTypeParametersAndFormals(
       libraryBuilder: libraryBuilder,
       declarationBuilder: declarationBuilder,
+      constructorBuilder: constructorBuilder,
       bodyBuilderContext: bodyBuilderContext,
       classHierarchy: classHierarchy,
       extensionScope: _fragment.enclosingCompilationUnit.extensionScope,
@@ -1155,12 +1156,14 @@ class DefaultEnumConstructorDeclaration
   void _buildTypeParametersAndFormalsForOutlineExpressions({
     required SourceLibraryBuilder libraryBuilder,
     required DeclarationBuilder declarationBuilder,
+    required SourceConstructorBuilder constructorBuilder,
     required BodyBuilderContext bodyBuilderContext,
     required ClassHierarchy classHierarchy,
   }) {
     _buildTypeParametersAndFormals(
       libraryBuilder: libraryBuilder,
       declarationBuilder: declarationBuilder,
+      constructorBuilder: constructorBuilder,
       bodyBuilderContext: bodyBuilderContext,
       classHierarchy: classHierarchy,
       extensionScope: _extensionScope,
@@ -1243,6 +1246,7 @@ class PrimaryConstructorDeclaration
   void _buildTypeParametersAndFormals({
     required SourceLibraryBuilder libraryBuilder,
     required DeclarationBuilder declarationBuilder,
+    required SourceConstructorBuilder constructorBuilder,
     required BodyBuilderContext bodyBuilderContext,
     required ClassHierarchy classHierarchy,
     required ExtensionScope extensionScope,
@@ -1265,11 +1269,11 @@ class PrimaryConstructorDeclaration
       // consuming too much memory.
       for (FormalParameterBuilder formal in formals!) {
         formal.buildOutlineExpressions(
-          libraryBuilder,
-          declarationBuilder,
+          libraryBuilder: libraryBuilder,
+          declarationBuilder: declarationBuilder,
+          memberBuilder: constructorBuilder,
           extensionScope: extensionScope,
           scope: typeParameterScope,
-          buildDefaultValue: true,
         );
       }
     }
@@ -1371,12 +1375,14 @@ class PrimaryConstructorDeclaration
   void _buildTypeParametersAndFormalsForOutlineExpressions({
     required SourceLibraryBuilder libraryBuilder,
     required DeclarationBuilder declarationBuilder,
+    required SourceConstructorBuilder constructorBuilder,
     required BodyBuilderContext bodyBuilderContext,
     required ClassHierarchy classHierarchy,
   }) {
     _buildTypeParametersAndFormals(
       libraryBuilder: libraryBuilder,
       declarationBuilder: declarationBuilder,
+      constructorBuilder: constructorBuilder,
       bodyBuilderContext: bodyBuilderContext,
       classHierarchy: classHierarchy,
       extensionScope: _fragment.enclosingCompilationUnit.extensionScope,

pkg/front_end/lib/src/fragment/enum_element.dart

@@ -183,7 +183,6 @@ class EnumElementDeclaration
     required SourcePropertyBuilder propertyBuilder,
     required Annotatable annotatable,
     required Uri annotatableFileUri,
-    required bool isClassInstanceMember,
   }) {}
 
   @override

pkg/front_end/lib/src/fragment/factory/declaration.dart

@@ -232,19 +232,13 @@ class FactoryDeclarationImpl
     }
 
     if (_fragment.formals != null) {
-      // For const constructors we need to include default parameter values
-      // into the outline. For all other formals we need to call
-      // buildOutlineExpressions to clear initializerToken to prevent
-      // consuming too much memory.
       for (FormalParameterBuilder formal in _fragment.formals!) {
         formal.buildOutlineExpressions(
-          libraryBuilder,
-          factoryBuilder.declarationBuilder,
+          libraryBuilder: libraryBuilder,
+          declarationBuilder: factoryBuilder.declarationBuilder,
+          memberBuilder: factoryBuilder,
           extensionScope: _fragment.enclosingCompilationUnit.extensionScope,
           scope: _fragment.typeParameterScope,
-          buildDefaultValue:
-              FormalParameterBuilder // force line break
-              .needsDefaultValuesBuiltAsOutlineExpressions(factoryBuilder),
         );
       }
     }

pkg/front_end/lib/src/fragment/field/declaration.dart

@@ -696,7 +696,6 @@ class RegularFieldDeclaration
     required SourcePropertyBuilder propertyBuilder,
     required Annotatable annotatable,
     required Uri annotatableFileUri,
-    required bool isClassInstanceMember,
   }) {}
 
   @override
@@ -716,7 +715,6 @@ class RegularFieldDeclaration
     required SourcePropertyBuilder propertyBuilder,
     required Annotatable annotatable,
     required Uri annotatableFileUri,
-    required bool isClassInstanceMember,
   }) {}
 
   @override

pkg/front_end/lib/src/fragment/getter/declaration.dart

@@ -50,7 +50,6 @@ abstract class GetterDeclaration {
     required SourcePropertyBuilder propertyBuilder,
     required Annotatable annotatable,
     required Uri annotatableFileUri,
-    required bool isClassInstanceMember,
   });
 
   void buildGetterOutlineNode({
@@ -166,16 +165,15 @@ class RegularGetterDeclaration
     required SourcePropertyBuilder propertyBuilder,
     required Annotatable annotatable,
     required Uri annotatableFileUri,
-    required bool isClassInstanceMember,
   }) {
     _encoding.buildOutlineExpressions(
       classHierarchy: classHierarchy,
       libraryBuilder: libraryBuilder,
       declarationBuilder: declarationBuilder,
+      propertyBuilder: propertyBuilder,
       bodyBuilderContext: createBodyBuilderContext(propertyBuilder),
       annotatable: annotatable,
       annotatableFileUri: annotatableFileUri,
-      isClassInstanceMember: isClassInstanceMember,
     );
   }
 

pkg/front_end/lib/src/fragment/getter/encoding.dart

@@ -135,10 +135,10 @@ sealed class GetterEncoding implements InferredTypeListener {
     required ClassHierarchy classHierarchy,
     required SourceLibraryBuilder libraryBuilder,
     required DeclarationBuilder? declarationBuilder,
+    required SourcePropertyBuilder propertyBuilder,
     required BodyBuilderContext bodyBuilderContext,
     required Annotatable annotatable,
     required Uri annotatableFileUri,
-    required bool isClassInstanceMember,
   });
 
   void buildOutlineNode({
@@ -236,10 +236,10 @@ mixin _DirectGetterEncodingMixin implements GetterEncoding {
     required ClassHierarchy classHierarchy,
     required SourceLibraryBuilder libraryBuilder,
     required DeclarationBuilder? declarationBuilder,
+    required SourcePropertyBuilder propertyBuilder,
     required BodyBuilderContext bodyBuilderContext,
     required Annotatable annotatable,
     required Uri annotatableFileUri,
-    required bool isClassInstanceMember,
   }) {
     buildMetadataForOutlineExpressions(
       libraryBuilder: libraryBuilder,
@@ -260,13 +260,12 @@ mixin _DirectGetterEncodingMixin implements GetterEncoding {
           // Coverage-ignore(suite): Not run.
           ?.builders,
     );
-    buildFormalsForOutlineExpressions(
-      libraryBuilder,
-      declarationBuilder,
-      _fragment.declaredFormals,
+    _fragment.declaredFormals.buildOutlineExpressions(
+      libraryBuilder: libraryBuilder,
+      declarationBuilder: declarationBuilder,
+      memberBuilder: propertyBuilder,
       extensionScope: _fragment.enclosingCompilationUnit.extensionScope,
       scope: _fragment.typeParameterScope,
-      isClassInstanceMember: isClassInstanceMember,
     );
   }
 
@@ -511,10 +510,10 @@ mixin _ExtensionInstanceGetterEncodingMixin implements GetterEncoding {
     required ClassHierarchy classHierarchy,
     required SourceLibraryBuilder libraryBuilder,
     required DeclarationBuilder? declarationBuilder,
+    required SourcePropertyBuilder propertyBuilder,
     required BodyBuilderContext bodyBuilderContext,
     required Annotatable annotatable,
     required Uri annotatableFileUri,
-    required bool isClassInstanceMember,
   }) {
     buildMetadataForOutlineExpressions(
       libraryBuilder: libraryBuilder,
@@ -536,13 +535,12 @@ mixin _ExtensionInstanceGetterEncodingMixin implements GetterEncoding {
           // Coverage-ignore(suite): Not run.
           ?.builders,
     );
-    buildFormalsForOutlineExpressions(
-      libraryBuilder,
-      declarationBuilder,
-      _fragment.declaredFormals,
+    _fragment.declaredFormals.buildOutlineExpressions(
+      libraryBuilder: libraryBuilder,
+      declarationBuilder: declarationBuilder,
+      memberBuilder: propertyBuilder,
       extensionScope: _fragment.enclosingCompilationUnit.extensionScope,
       scope: _fragment.typeParameterScope,
-      isClassInstanceMember: isClassInstanceMember,
     );
 
     buildTypeParametersForOutlineExpressions(
@@ -551,13 +549,12 @@ mixin _ExtensionInstanceGetterEncodingMixin implements GetterEncoding {
       bodyBuilderContext,
       _clonedDeclarationTypeParameters,
     );
-    buildFormalForOutlineExpressions(
-      libraryBuilder,
-      declarationBuilder,
-      _thisFormal,
+    _thisFormal.buildOutlineExpressions(
+      libraryBuilder: libraryBuilder,
+      declarationBuilder: declarationBuilder,
+      memberBuilder: propertyBuilder,
       extensionScope: _fragment.enclosingCompilationUnit.extensionScope,
       scope: _fragment.typeParameterScope,
-      isClassInstanceMember: isClassInstanceMember,
     );
   }