Elements. Remove V1 MixinElement.

Change-Id: I220636152100b901c4100fc1d0558a1b7ebf1c7d
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/423163
Commit-Queue: Konstantin Shcheglov <[email protected]>
Reviewed-by: Brian Wilkerson <[email protected]>

Author: scheglov

pkg/analyzer/api.txt

@@ -3012,7 +3012,6 @@ package:analyzer/dart/element/element.dart:
     libraryImportPrefixes (getter: List<PrefixElement>)
     libraryImports (getter: List<LibraryImportElement>)
     lineInfo (getter: LineInfo)
-    mixins (getter: List<MixinElement>)
     parts (getter: List<PartElement>)
     scope (getter: Scope)
     session (getter: AnalysisSession)
@@ -3352,12 +3351,6 @@ package:analyzer/dart/element/element.dart:
   MethodElement (class extends Object implements ClassMemberElement, ExecutableElement, deprecated):
     new (constructor: MethodElement Function())
     declaration (getter: MethodElement)
-  MixinElement (class extends Object implements InterfaceElement, deprecated):
-    new (constructor: MixinElement Function())
-    augmented (getter: AugmentedMixinElement, deprecated)
-    isBase (getter: bool)
-    superclassConstraints (getter: List<InterfaceType>)
-    isImplementableIn (method: bool Function(LibraryElement))
   MultiplyDefinedElement (class extends Object implements Element, deprecated):
     new (constructor: MultiplyDefinedElement Function())
     conflictingElements (getter: List<Element>)

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

@@ -291,9 +291,6 @@ abstract class CompilationUnitElement implements UriReferencedElement {
   /// The [LineInfo] for the [source].
   LineInfo get lineInfo;
 
-  /// The mixins declared in this compilation unit.
-  List<MixinElement> get mixins;
-
   /// The parts included by this unit.
   List<PartElement> get parts;
 
@@ -1811,38 +1808,6 @@ abstract class MethodElement implements ClassMemberElement, ExecutableElement {
   MethodElement get declaration;
 }
 
-/// An element that represents a mixin.
-///
-/// Clients may not extend, implement or mix-in this class.
-@Deprecated('Use MixinElement2 instead')
-abstract class MixinElement implements InterfaceElement {
-  @Deprecated(elementModelDeprecationMsg)
-  @override
-  AugmentedMixinElement get augmented;
-
-  /// Whether the mixin is a base mixin.
-  ///
-  /// A mixin is a base mixin if it has an explicit `base` modifier.
-  /// The base modifier allows a mixin to be mixed in, but not implemented.
-  bool get isBase;
-
-  /// The superclass constraints defined for this mixin.
-  ///
-  /// If the declaration does not have an `on` clause, then the list will
-  /// contain the type for the class `Object`.
-  ///
-  /// <b>Note:</b> Because the element model represents the state of the code,
-  /// it is possible for it to be semantically invalid. In particular, it is not
-  /// safe to assume that the inheritance structure of a class does not contain
-  /// a cycle. Clients that traverse the inheritance structure must explicitly
-  /// guard against infinite loops.
-  List<InterfaceType> get superclassConstraints;
-
-  /// Whether the element, assuming that it is within scope, is
-  /// implementable to classes, mixins, and enums in the given [library].
-  bool isImplementableIn(LibraryElement library);
-}
-
 /// A pseudo-element that represents multiple elements defined within a single
 /// scope that have the same name. This situation is not allowed by the
 /// language, so objects implementing this interface always represent an error.

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

@@ -228,21 +228,6 @@ class AugmentedInterfaceElementImpl extends AugmentedInstanceElementImpl
   }
 }
 
-@Deprecated(elementModelDeprecationMsg)
-class AugmentedMixinElementImpl extends AugmentedInterfaceElementImpl
-    implements AugmentedMixinElement {
-  AugmentedMixinElementImpl(super.firstFragment);
-
-  @override
-  MixinElementImpl get firstFragment {
-    return super.firstFragment as MixinElementImpl;
-  }
-
-  @override
-  List<InterfaceType> get superclassConstraints =>
-      firstFragment.superclassConstraints;
-}
-
 class BindPatternVariableElementImpl extends PatternVariableElementImpl
     implements
         // ignore: deprecated_member_use_from_same_package,analyzer_use_new_elements
@@ -1160,7 +1145,6 @@ class CompilationUnitElementImpl extends UriReferencedElementImpl
     return super.metadata;
   }
 
-  @override
   List<MixinElementImpl> get mixins {
     return _mixins;
   }
@@ -1288,19 +1272,6 @@ class CompilationUnitElementImpl extends UriReferencedElementImpl
     builder.writeCompilationUnitElement(this);
   }
 
-  /// Returns the mixin defined in this compilation unit that has the given
-  /// [name], or `null` if this compilation unit does not define a mixin with
-  /// the given name.
-  @Deprecated(elementModelDeprecationMsg)
-  MixinElement? getMixin(String name) {
-    for (var mixin in mixins) {
-      if (mixin.name == name) {
-        return mixin;
-      }
-    }
-    return null;
-  }
-
   void setLinkedData(Reference reference, ElementLinkedData linkedData) {
     this.reference = reference;
     reference.element = this;
@@ -7532,17 +7503,6 @@ class LibraryElementImpl extends ElementImpl
     return _getElementByName(getters, name);
   }
 
-  @Deprecated(elementModelDeprecationMsg)
-  MixinElement? getMixin(String name) {
-    for (var unitElement in units) {
-      var element = unitElement.getMixin(name);
-      if (element != null) {
-        return element;
-      }
-    }
-    return null;
-  }
-
   @override
   MixinElement2? getMixin2(String name) {
     return _getElementByName(mixins, name);
@@ -8589,10 +8549,7 @@ abstract class MethodElementOrMember
 
 /// A [ClassElementImpl] representing a mixin declaration.
 class MixinElementImpl extends ClassOrMixinElementImpl
-    implements
-        // ignore:deprecated_member_use_from_same_package,analyzer_use_new_elements
-        MixinElement,
-        MixinFragment {
+    implements MixinFragment {
   List<InterfaceTypeImpl> _superclassConstraints = const [];
 
   /// Names of methods, getters, setters, and operators that this mixin
@@ -8606,10 +8563,6 @@ class MixinElementImpl extends ClassOrMixinElementImpl
   /// given [offset] in the file that contains the declaration of this element.
   MixinElementImpl(super.name, super.offset);
 
-  @Deprecated(elementModelDeprecationMsg)
-  @override
-  AugmentedMixinElement get augmented => AugmentedMixinElementImpl(this);
-
   @override
   MixinElementImpl2 get element {
     linkedData?.read(this);
@@ -8663,15 +8616,6 @@ class MixinElementImpl extends ClassOrMixinElementImpl
   void appendTo(ElementDisplayStringBuilder builder) {
     builder.writeMixinElement(this);
   }
-
-  @Deprecated('Use MixinElement2 instead')
-  @override
-  bool isImplementableIn(LibraryElement library) {
-    if (library == this.library) {
-      return true;
-    }
-    return !isBase;
-  }
 }
 
 class MixinElementImpl2 extends InterfaceElementImpl2 implements MixinElement2 {