Added polymorphic check.

Author: egorshamshura

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -1795,6 +1795,7 @@ def note_unsatisfied_trait_reason
            "%NTCBase{has a non-trivially-copyable base %1}|"
            "%NTCField{has a non-trivially-copyable member %1 of type %2}|"
            "%NonEmptyMember{has a non-static data member %1 of type %2}|"
+           "%PolymorphicType{is a polymorphic type}|"
            "%VirtualFunction{has a virtual function %1}|"
            "%NonEmptyBase{has a base class %1 that is not empty}|"
            "%NonZeroLengthField{field %1 is a non-zero-length bit-field}|"

clang/lib/Sema/SemaTypeTraits.cpp

@@ -2694,6 +2694,11 @@ static void DiagnoseNonAggregateReason(Sema &SemaRef, SourceLocation Loc,
     }
   }
 
+  if (D->isPolymorphic())
+    SemaRef.Diag(Loc, diag::note_unsatisfied_trait_reason)
+        << diag::TraitNotSatisfiedReason::PolymorphicType
+        << D->getSourceRange();
+
   for (const CXXMethodDecl *Method : D->methods()) {
     if (Method->isVirtual()) {
       SemaRef.Diag(Loc, diag::note_unsatisfied_trait_reason)

clang/test/SemaCXX/type-traits-unsatisfied-diags.cpp

@@ -959,6 +959,7 @@ namespace is_aggregate {
   // expected-note@-1 {{because it has a virtual function 'foo'}} \
   // expected-note@-1 {{because it has a virtual base}} \
   // expected-note@-1 {{'S7' is not aggregate}} \
+  // expected-note@-1 {{because it is a polymorphic type}} \
   // expected-note@#ag-S7 {{'S7' defined here}}
 
   static_assert(__is_aggregate(S7[10]));