[Sema] Implement several unary type traits more accurately

is_empty, is_polymorphic, and is_abstract didn't handle incomplete types
correctly.  Only non-union class types must be complete for these
traits.

is_final and is_sealed don't care about the particular spelling of the
FinalAttr.

is_interface_class should always return false regardless of its input.
The type trait can only be satisfied in a mode we do not support (/CLR).

llvm-svn: 253184

1 files changed, 32 insertions, 19 deletions

diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index 4b7db59444b..da34791395b 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -3550,27 +3550,43 @@ static bool CheckUnaryTypeTraitTypeCompleteness(Sema &S, TypeTrait UTT,
   case UTT_IsVolatile:
   case UTT_IsSigned:
   case UTT_IsUnsigned:
+
+  // This type trait always returns false, checking the type is moot.
+  case UTT_IsInterfaceClass:
+    return true;
+
+  // C++14 [meta.unary.prop]:
+  //   If T is a non-union class type, T shall be a complete type.
+  case UTT_IsEmpty:
+  case UTT_IsPolymorphic:
+  case UTT_IsAbstract:
+    if (const auto *RD = ArgTy->getAsCXXRecordDecl())
+      if (!RD->isUnion())
+        return !S.RequireCompleteType(
+            Loc, ArgTy, diag::err_incomplete_type_used_in_type_trait_expr);
+    return true;
+
+  // C++14 [meta.unary.prop]:
+  //   If T is a class type, T shall be a complete type.
+  case UTT_IsFinal:
+  case UTT_IsSealed:
+    if (ArgTy->getAsCXXRecordDecl())
+      return !S.RequireCompleteType(
+          Loc, ArgTy, diag::err_incomplete_type_used_in_type_trait_expr);
     return true;
 
-    // C++0x [meta.unary.prop] Table 49 requires the following traits to be
-    // applied to a complete type.
+  // C++0x [meta.unary.prop] Table 49 requires the following traits to be
+  // applied to a complete type.
   case UTT_IsTrivial:
   case UTT_IsTriviallyCopyable:
   case UTT_IsStandardLayout:
   case UTT_IsPOD:
   case UTT_IsLiteral:
-  case UTT_IsEmpty:
-  case UTT_IsPolymorphic:
-  case UTT_IsAbstract:
-  case UTT_IsInterfaceClass:
+
   case UTT_IsDestructible:
   case UTT_IsNothrowDestructible:
     // Fall-through
 
-  // These traits require a complete type.
-  case UTT_IsFinal:
-  case UTT_IsSealed:
-
     // These trait expressions are designed to help implement predicates in
     // [meta.unary.prop] despite not being named the same. They are specified
     // by both GCC and the Embarcadero C++ compiler, and require the complete
@@ -3729,24 +3745,21 @@ static bool EvaluateUnaryTypeTrait(Sema &Self, TypeTrait UTT,
     return false;
   case UTT_IsPolymorphic:
     if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
-      return RD->isPolymorphic();
+      return !RD->isUnion() && RD->isPolymorphic();
     return false;
   case UTT_IsAbstract:
     if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
-      return RD->isAbstract();
+      return !RD->isUnion() && RD->isAbstract();
     return false;
+  // __is_interface_class only returns true when CL is invoked in /CLR mode and
+  // even then only when it is used with the 'interface struct ...' syntax
+  // Clang doesn't support /CLR which makes this type trait moot.
   case UTT_IsInterfaceClass:
-    if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
-      return RD->isInterface();
     return false;
   case UTT_IsFinal:
-    if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
-      return RD->hasAttr<FinalAttr>();
-    return false;
   case UTT_IsSealed:
     if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
-      if (FinalAttr *FA = RD->getAttr<FinalAttr>())
-        return FA->isSpelledAsSealed();
+      return RD->hasAttr<FinalAttr>();
     return false;
   case UTT_IsSigned:
     return T->isSignedIntegerType();