diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 6581d4c604eb2..4ef8fd66545e7 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -20264,9 +20264,10 @@ Decl *Sema::ActOnEnumConstant(Scope *S, Decl *theEnumDecl, Decl *lastEnumConst,
   // different from T:
   // - every enumerator of every member of class T that is an unscoped
   // enumerated type
-  if (getLangOpts().CPlusPlus && !TheEnumDecl->isScoped())
-    DiagnoseClassNameShadow(TheEnumDecl->getDeclContext(),
-                            DeclarationNameInfo(Id, IdLoc));
+  if (getLangOpts().CPlusPlus && !TheEnumDecl->isScoped() &&
+      DiagnoseClassNameShadow(TheEnumDecl->getDeclContext(),
+                              DeclarationNameInfo(Id, IdLoc)))
+    return nullptr;
 
   EnumConstantDecl *New =
     CheckEnumConstant(TheEnumDecl, LastEnumConst, IdLoc, Id, Val);
diff --git a/clang/test/CXX/class/class.mem/p13.cpp b/clang/test/CXX/class/class.mem/p13.cpp
index d947586c41940..a30aa5d0b2ee3 100644
--- a/clang/test/CXX/class/class.mem/p13.cpp
+++ b/clang/test/CXX/class/class.mem/p13.cpp
@@ -114,3 +114,12 @@ template<typename B> struct CtorDtorName : B {
   CtorDtorName();
   ~CtorDtorName(); // expected-error {{identifier 'CtorDtorName' after '~' in destructor name does not name a type}}
 };
+
+struct S { // expected-note {{'S' declared here}}
+  enum E {
+    R = 11,
+    S = 12  // expected-error {{member 'S' has the same name as its class}}
+  };
+  static_assert(E::R == 11, "E::R is not 11");
+  static_assert(E::S == 12, "E::S is not 12");  // expected-error {{no member named 'S' in 'S::E'}}
+};