[analyzer] Add mixin classes to ClassElementImpl

Change-Id: I41cbbf218a9c8d7c26fa8f32e3b8022c51b42789
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/275521
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Commit-Queue: Kallen Tu <kallentu@google.com>

pkg/analyzer/lib/src/dart/analysis/driver.dart

@@ -85,7 +85,7 @@ import 'package:analyzer/src/util/performance/operation_performance.dart';
 /// TODO(scheglov) Clean up the list of implicitly analyzed files.
 class AnalysisDriver implements AnalysisDriverGeneric {
   /// The version of data format, should be incremented on every format change.
-  static const int DATA_VERSION = 253;
+  static const int DATA_VERSION = 254;
 
   /// The number of exception contexts allowed to write. Once this field is
   /// zero, we stop writing any new exception contexts in this process.

pkg/analyzer/lib/src/dart/ast/to_source_visitor.dart

@@ -194,6 +194,7 @@ class ToSourceVisitor implements AstVisitor<void> {
     _visitToken(node.abstractKeyword, suffix: ' ');
     _visitToken(node.macroKeyword, suffix: ' ');
     _visitToken(node.sealedKeyword, suffix: ' ');
+    _visitToken(node.mixinKeyword, suffix: ' ');
     sink.write('class ');
     _visitToken(node.name);
     _visitNode(node.typeParameters);
@@ -212,6 +213,7 @@ class ToSourceVisitor implements AstVisitor<void> {
     _visitToken(node.abstractKeyword, suffix: ' ');
     _visitToken(node.macroKeyword, suffix: ' ');
     _visitToken(node.sealedKeyword, suffix: ' ');
+    _visitToken(node.mixinKeyword, suffix: ' ');
     sink.write('class ');
     _visitToken(node.name);
     _visitNode(node.typeParameters);

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

@@ -748,6 +748,14 @@ class ClassElementImpl extends ClassOrMixinElementImpl implements ClassElement {
     setModifier(Modifier.MIXIN_APPLICATION, isMixinApplication);
   }
 
+  bool get isMixinClass {
+    return hasModifier(Modifier.MIXIN_CLASS);
+  }
+
+  set isMixinClass(bool isMixinClass) {
+    setModifier(Modifier.MIXIN_CLASS, isMixinClass);
+  }
+
   @override
   bool get isValidMixin {
     final supertype = this.supertype;
@@ -4841,29 +4849,32 @@ class Modifier implements Comparable<Modifier> {
   /// Indicates that a class is a mixin application.
   static const Modifier MIXIN_APPLICATION = Modifier('MIXIN_APPLICATION', 19);
 
-  static const Modifier PROMOTABLE = Modifier('IS_PROMOTABLE', 20);
+  /// Indicates that a class is a mixin class.
+  static const Modifier MIXIN_CLASS = Modifier('MIXIN_CLASS', 20);
+
+  static const Modifier PROMOTABLE = Modifier('IS_PROMOTABLE', 21);
 
   /// Indicates that the modifier 'sealed' was applied to the element.
-  static const Modifier SEALED = Modifier('SEALED', 21);
+  static const Modifier SEALED = Modifier('SEALED', 22);
 
   /// Indicates that the pseudo-modifier 'set' was applied to the element.
-  static const Modifier SETTER = Modifier('SETTER', 22);
+  static const Modifier SETTER = Modifier('SETTER', 23);
 
   /// See [TypeParameterizedElement.isSimplyBounded].
-  static const Modifier SIMPLY_BOUNDED = Modifier('SIMPLY_BOUNDED', 23);
+  static const Modifier SIMPLY_BOUNDED = Modifier('SIMPLY_BOUNDED', 24);
 
   /// Indicates that the modifier 'static' was applied to the element.
-  static const Modifier STATIC = Modifier('STATIC', 24);
+  static const Modifier STATIC = Modifier('STATIC', 25);
 
   /// Indicates that the element does not appear in the source code but was
   /// implicitly created. For example, if a class does not define any
   /// constructors, an implicit zero-argument constructor will be created and it
   /// will be marked as being synthetic.
-  static const Modifier SYNTHETIC = Modifier('SYNTHETIC', 25);
+  static const Modifier SYNTHETIC = Modifier('SYNTHETIC', 26);
 
   /// Indicates that the element was appended to this enclosing element to
   /// simulate temporary the effect of applying augmentation.
-  static const Modifier TEMP_AUGMENTATION = Modifier('TEMP_AUGMENTATION', 26);
+  static const Modifier TEMP_AUGMENTATION = Modifier('TEMP_AUGMENTATION', 27);
 
   static const List<Modifier> values = [
     ABSTRACT,
@@ -4885,6 +4896,7 @@ class Modifier implements Comparable<Modifier> {
     LATE,
     MACRO,
     MIXIN_APPLICATION,
+    MIXIN_CLASS,
     PROMOTABLE,
     SEALED,
     SETTER,

pkg/analyzer/lib/src/summary2/element_builder.dart

@@ -95,6 +95,7 @@ class ElementBuilder extends ThrowingAstVisitor<void> {
       element.isSealed = true;
       element.isAbstract = true;
     }
+    element.isMixinClass = node.mixinKeyword != null;
     element.metadata = _buildAnnotations(node.metadata);
     _setCodeRange(element, node);
     _setDocumentation(element, node);
@@ -133,6 +134,7 @@ class ElementBuilder extends ThrowingAstVisitor<void> {
       element.isAbstract = true;
     }
     element.isMixinApplication = true;
+    element.isMixinClass = node.mixinKeyword != null;
     element.metadata = _buildAnnotations(node.metadata);
     _setCodeRange(element, node);
     _setDocumentation(element, node);

pkg/analyzer/lib/src/summary2/element_flags.dart

@@ -10,14 +10,16 @@ class ClassElementFlags {
   static const int _isAbstract = 1 << 0;
   static const int _isMacro = 1 << 1;
   static const int _isMixinApplication = 1 << 2;
-  static const int _isSealed = 1 << 3;
+  static const int _isMixinClass = 1 << 3;
-  static const int _isSimplyBounded = 1 << 4;
+  static const int _isSealed = 1 << 4;
+  static const int _isSimplyBounded = 1 << 5;
 
   static void read(SummaryDataReader reader, ClassElementImpl element) {
     var byte = reader.readByte();
     element.isAbstract = (byte & _isAbstract) != 0;
     element.isMacro = (byte & _isMacro) != 0;
     element.isMixinApplication = (byte & _isMixinApplication) != 0;
+    element.isMixinClass = (byte & _isMixinClass) != 0;
     element.isSealed = (byte & _isSealed) != 0;
     element.isSimplyBounded = (byte & _isSimplyBounded) != 0;
   }
@@ -27,6 +29,7 @@ class ClassElementFlags {
     result |= element.isAbstract ? _isAbstract : 0;
     result |= element.isMacro ? _isMacro : 0;
     result |= element.isMixinApplication ? _isMixinApplication : 0;
+    result |= element.isMixinClass ? _isMixinClass : 0;
     result |= element.isSealed ? _isSealed : 0;
     result |= element.isSimplyBounded ? _isSimplyBounded : 0;
     sink.writeByte(result);

pkg/analyzer/test/src/dart/ast/to_source_visitor_test.dart

@@ -437,6 +437,16 @@ macro class A {}
     );
   }
 
+  void test_visitClassDeclaration_mixin() {
+    var findNode = _parseStringToFindNode(r'''
+mixin class A {}
+''');
+    _assertSource(
+      'mixin class A {}',
+      findNode.classDeclaration('class A'),
+    );
+  }
+
   void test_visitClassDeclaration_multipleMember() {
     final code = 'class C {var a; var b;}';
     final findNode = _parseStringToFindNode('''
@@ -590,6 +600,16 @@ $code
     _assertSource(code, findNode.classTypeAlias(code));
   }
 
+  void test_visitClassTypeAlias_mixin() {
+    var findNode = _parseStringToFindNode(r'''
+mixin class A = S with M;
+''');
+    _assertSource(
+      'mixin class A = S with M;',
+      findNode.classTypeAlias('class A'),
+    );
+  }
+
   void test_visitClassTypeAlias_parameters_abstract() {
     final code = 'abstract class C<E> = S with M;';
     final findNode = _parseStringToFindNode('''

pkg/analyzer/test/src/summary/element_text.dart

@@ -291,6 +291,7 @@ class _ElementWriter {
         _writeIf(e.isAbstract, 'abstract ');
         _writeIf(e.isMacro, 'macro ');
         _writeIf(e.isSealed, 'sealed ');
+        _writeIf(e.isMixinClass, 'mixin ');
       }
       _writeIf(!e.isSimplyBounded, 'notSimplyBounded ');
 
@@ -1088,6 +1089,11 @@ extension on ClassElement {
     return self is ClassElementImpl && self.isMacro;
   }
 
+  bool get isMixinClass {
+    final self = this;
+    return self is ClassElementImpl && self.isMixinClass;
+  }
+
   bool get isSealed {
     final self = this;
     return self is ClassElementImpl && self.isSealed;

pkg/analyzer/test/src/summary/elements_test.dart

@@ -6828,6 +6828,18 @@ library
 ''');
   }
 
+  test_class_mixin_class() async {
+    var library = await buildLibrary('mixin class C {}');
+    checkElementText(library, r'''
+library
+  definingUnit
+    classes
+      mixin class C @12
+        constructors
+          synthetic @-1
+''');
+  }
+
   test_class_mixins() async {
     var library = await buildLibrary('''
 class C extends D with E, F, G {}
@@ -8931,6 +8943,35 @@ library
 ''');
   }
 
+  test_classAlias_mixin_class() async {
+    var library = await buildLibrary('''
+mixin class C = Object with M;
+mixin M {}
+''');
+    checkElementText(library, r'''
+library
+  definingUnit
+    classes
+      mixin class alias C @12
+        supertype: Object
+        mixins
+          M
+        constructors
+          synthetic const @-1
+            constantInitializers
+              SuperConstructorInvocation
+                superKeyword: super @0
+                argumentList: ArgumentList
+                  leftParenthesis: ( @0
+                  rightParenthesis: ) @0
+                staticElement: dart:core::@class::Object::@constructor::new
+    mixins
+      mixin M @37
+        superclassConstraints
+          Object
+''');
+  }
+
   test_classAlias_notSimplyBounded_self() async {
     var library = await buildLibrary('''
 class C<T extends C> = D with E;