Elements. Remove FieldElementOrMember.

Change-Id: Ied15d4796bc42e58e932fb2689be2d627a047d2e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/437520
Reviewed-by: Paul Berry <[email protected]>
Commit-Queue: Konstantin Shcheglov <[email protected]>

Author: scheglov

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

@@ -2945,16 +2945,6 @@ class FieldElementImpl extends PropertyInducingElementImpl
   DartObject? computeConstantValue() => firstFragment.computeConstantValue();
 }
 
-/// Common base class for all analyzer-internal classes that implement
-/// `FieldElement`.
-abstract class FieldElementOrMember implements PropertyInducingElementOrMember {
-  @override
-  FieldFragmentImpl get declaration;
-
-  @override
-  TypeImpl get type;
-}
-
 class FieldFormalParameterElementImpl extends FormalParameterElementImpl
     implements FieldFormalParameterElement {
   FieldFormalParameterElementImpl(super.firstFragment);
@@ -3032,7 +3022,7 @@ class FieldFormalParameterFragmentImpl extends FormalParameterFragmentImpl
 
 class FieldFragmentImpl extends PropertyInducingFragmentImpl
     with ConstVariableFragment
-    implements FieldElementOrMember, FieldFragment {
+    implements FieldFragment {
   /// True if this field inherits from a covariant parameter. This happens
   /// when it overrides a field in a supertype that is covariant.
   bool inheritsCovariant = false;

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

@@ -450,8 +450,7 @@ class FieldFormalParameterMember extends ParameterMember
 
 /// A field element defined in a parameterized type where the values of the type
 /// parameters are known.
-class FieldMember extends VariableMember
-    implements FieldElementOrMember, FieldElement2OrMember {
+class FieldMember extends VariableMember implements FieldElement2OrMember {
   /// Initialize a newly created element to represent a field, based on the
   /// [declaration], with applied [substitution].
   FieldMember({
@@ -617,16 +616,6 @@ class FieldMember extends VariableMember
       substitution: substitution,
     );
   }
-
-  static FieldElementOrMember from2(
-    FieldFragmentImpl element,
-    MapSubstitution substitution,
-  ) {
-    if (substitution.map.isEmpty) {
-      return element;
-    }
-    return FieldMember(declaration: element, substitution: substitution);
-  }
 }
 
 /// A getter element defined in a parameterized type where the values of the

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

@@ -247,16 +247,6 @@ extension FieldElementImplExtension on FieldFragmentImpl {
   }
 }
 
-extension FieldElementOrMemberExtension on FieldElementOrMember {
-  FieldElement2OrMember get asElement2 {
-    return switch (this) {
-      FieldFragmentImpl(:var element) => element,
-      FieldMember member => member,
-      _ => throw UnsupportedError('Unsupported type: $runtimeType'),
-    };
-  }
-}
-
 extension FormalParameterElementExtension on FormalParameterElement {
   void appendToWithoutDelimiters(
     StringBuffer buffer, {