Fix @protected access check from within defining class (#26614).

pkg/analyzer/lib/src/generated/resolver.dart

 // Copyright (c) 2014, 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.
 
 library analyzer.src.generated.resolver;
 
 import 'dart:collection';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
@@ skipping 682 matching lines @@
         node.getAncestor((AstNode node) => node is MethodDeclaration);
     if (decl == null) {
       _errorReporter.reportErrorForNode(
           HintCode.INVALID_USE_OF_PROTECTED_MEMBER,
           node,
           [node.methodName.toString(), definingClass.name]);
       return;
     }
 
     ClassElement invokingClass = decl.element?.enclosingElement;
-    if (!_hasSuperType(invokingClass, definingClass.type)) {
+    if (!_hasTypeOrSuperType(invokingClass, definingClass.type)) {
       _errorReporter.reportErrorForNode(
           HintCode.INVALID_USE_OF_PROTECTED_MEMBER,
           node,
           [node.methodName.toString(), definingClass.name]);
     }
   }
 
   /**
    * Produces a hint if the given identifier is a protected field or getter
    * accessed outside a subclass.
    */
   void _checkForInvalidProtectedPropertyAccess(SimpleIdentifier identifier) {
     if (identifier.inDeclarationContext()) {
       return;
     }
     Element element = identifier.bestElement;
     if (element is PropertyAccessorElement &&
         element.enclosingElement is ClassElement &&
         (element.isProtected || element.variable.isProtected)) {
       ClassElement definingClass = element.enclosingElement;
       ClassDeclaration accessingClass =
           identifier.getAncestor((AstNode node) => node is ClassDeclaration);
 
       if (accessingClass == null) {
         _errorReporter.reportErrorForNode(
             HintCode.INVALID_USE_OF_PROTECTED_MEMBER,
             identifier,
             [identifier.name.toString(), definingClass.name]);
-      } else if (!_hasSuperType(accessingClass.element, definingClass.type)) {
+      } else if (!_hasTypeOrSuperType(
+          accessingClass.element, definingClass.type)) {
         _errorReporter.reportErrorForNode(
             HintCode.INVALID_USE_OF_PROTECTED_MEMBER,
             identifier,
             [identifier.name.toString(), definingClass.name]);
       }
     }
   }
 
   /**
    * Check that the imported library does not define a loadLibrary function. The import has already
@@ skipping 256 matching lines @@
 //        _errorReporter.reportErrorForNode(
 //            HintCode.OVERRIDE_EQUALS_BUT_NOT_HASH_CODE,
 //            node.name,
 //            [classElement.displayName]);
 //        return true;
 //      }
 //    }
 //    return false;
 //  }
 
-  bool _hasSuperClassOrMixin(ClassElement element, InterfaceType type) {
-    List<ClassElement> seenClasses = <ClassElement>[];
-    while (element != null && !seenClasses.contains(element)) {
-      if (element.type == type) {
-        return true;
-      }
-
-      if (element.mixins.any((InterfaceType t) => t == type)) {
-        return true;
-      }
-
-      seenClasses.add(element);
-      element = element.supertype?.element;
-    }
-
-    return false;
-  }
-
-  bool _hasSuperType(ClassElement element, InterfaceType type) =>
-      element != null && element.allSupertypes.contains(type);
+  bool _hasTypeOrSuperType(ClassElement element, InterfaceType type) =>
+      element != null &&
+      (element.type == type || element.allSupertypes.contains(type));
 
   /**
    * Given a parenthesized expression, this returns the parent (or recursively grand-parent) of the
    * expression that is a parenthesized expression, but whose parent is not a parenthesized
    * expression.
    *
    * For example given the code `(((e)))`: `(e) -> (((e)))`.
    *
    * @param parenthesizedExpression some expression whose parent is a parenthesized expression
    * @return the first parent or grand-parent that is a parenthesized expression, that does not have
@@ skipping 9931 matching lines @@
       return null;
     }
     if (identical(node.staticElement, variable)) {
       if (node.inSetterContext()) {
         result = true;
       }
     }
     return null;
   }
 }