fix #27210, remove TypeParameterMember equality

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

Index: pkg/analyzer/lib/src/generated/type_system.dart
diff --git a/pkg/analyzer/lib/src/generated/type_system.dart b/pkg/analyzer/lib/src/generated/type_system.dart
index 5574aed89f2b09b3e9abf83af23f13bfb8b2f982..51945ec29601fdc2ee281a695d9af796f451f072 100644
--- a/pkg/analyzer/lib/src/generated/type_system.dart
+++ b/pkg/analyzer/lib/src/generated/type_system.dart
@@ -851,7 +851,7 @@ class StrongTypeSystemImpl extends TypeSystem {
     if (identical(i1, i2)) {
       return true;
     }
-    
+
     // Guard recursive calls
     _GuardedSubtypeChecker<InterfaceType> guardedInterfaceSubtype = _guard(
         (DartType i1, DartType i2, Set<Element> visited) =>
@@ -932,14 +932,15 @@ class StrongTypeSystemImpl extends TypeSystem {
     //  True if T == S
     //  Or true if bound of S is S' and S' <: T
     if (t1 is TypeParameterType) {
-      if (t1 == t2) {
+      if (t2 is TypeParameterType &&
+          t1.definition == t2.definition &&
+          t1.bound == t2.bound) {
         return true;
       }
       if (guardedInferTypeParameter(t1, t2, visited)) {
         return true;
       }
-      DartType bound = t1.element.bound;
-      return bound == null ? false : guardedSubtype(bound, t2, visited);
+      return guardedSubtype(t1.bound, t2, visited);
     }
 
     if (t2 is TypeParameterType) {