fix regression

Author: cor3ntin

clang/lib/Sema/SemaExprCXX.cpp

@@ -3747,7 +3747,7 @@ Sema::ActOnCXXDelete(SourceLocation StartLoc, bool UseGlobal,
     } else if (!Pointee->isDependentType()) {
       // FIXME: This can result in errors if the definition was imported from a
       // module but is hidden.
-      if (!Pointee->isStructureOrClassType() ||
+      if (Pointee->isEnumeralType() ||
           !RequireCompleteType(StartLoc, Pointee,
                                LangOpts.CPlusPlus26
                                    ? diag::err_delete_incomplete

clang/test/SemaCXX/new-delete.cpp

@@ -545,6 +545,15 @@ enum GH99278_1 {
     zero = decltype(delete static_cast<GH99278_1*>(nullptr), 0){}
     // expected-warning@-1 {{expression with side effects has no effect in an unevaluated context}}
 };
+template <typename = void>
+struct GH99278_2 {
+  union b {};
+  struct c {
+    c() { delete d; }
+    b *d;
+  } f;
+};
+GH99278_2<void> e;
 #endif
 
 struct PlacementArg {};