Fix assert in the call to isOpenMPRebuildMemberExpr

[jyu2]

Summary

This is to fix https://github.com/llvm/llvm-project/issues/56884

The problem is in isOpenMPRebuildMemberExpr, it is only need to rebuild
for field expression. No need for member function call.

The fix is to check field for member expression and skip rebuild for member
function call

[ABataev]

LG

clang/lib/Sema/SemaOpenMP.cpp

return (isOpenMPTargetExecutionDirective(DSAStack->getCurrentDirective()) &&
              [](OpenMPDirectiveKind K, const DeclarationNameInfo &,
                 SourceLocation) -> bool {
                return isOpenMPTargetExecutionDirective(K);
              },
              false);
 }
 
 bool Sema::isOpenMPRebuildMemberExpr(ValueDecl *D) {
+  // Only rebuild for Field.
+  if (!dyn_cast<FieldDecl>(D))
+    return false;
   DSAStackTy::DSAVarData DVarPrivate = DSAStack->hasDSA(
       D,
       [](OpenMPClauseKind C, bool AppliedToPointee,
          DefaultDataSharingAttributes DefaultAttr) {
         return isOpenMPPrivate(C) && !AppliedToPointee &&
                (DefaultAttr == DSA_firstprivate || DefaultAttr == DSA_private);
       },
       [](OpenMPDirectiveKind) { return true; },

clang/test/OpenMP/parallel_default_messages.cpp

#pragma omp parallel default(private) // expected-note 2 {{explicit data sharing attribute requested here}}
   {
     ++x; // expected-error {{variable 'x' must have explicitly specified data sharing attributes}}
     ++y; // expected-error {{variable 'y' must have explicitly specified data sharing attributes}}
   }
 #endif
 
   return 0;
 }
+
+class A{
+  void a() {
+    #pragma omp parallel
+    a(b); // expected-error {{use of undeclared identifier 'b'}}
+ }
+};