[Clang] Remove __is_nullptr

clang/docs/LanguageExtensions.rst

@@ -1614,10 +1614,6 @@ The following type trait primitives are supported by Clang. Those traits marked
 * ``__is_nothrow_assignable`` (C++, MSVC 2013)
 * ``__is_nothrow_constructible`` (C++, MSVC 2013)
 * ``__is_nothrow_destructible`` (C++, MSVC 2013)
-* ``__is_nullptr`` (C++, GNU, Microsoft, Embarcadero):
-  Returns true for ``std::nullptr_t`` and false for everything else. The
-  corresponding standard library feature is ``std::is_null_pointer``, but
-  ``__is_null_pointer`` is already in use by some implementations.
 * ``__is_object`` (C++, Embarcadero)
 * ``__is_pod`` (C++, GNU, Microsoft, Embarcadero):
   Note, the corresponding standard trait was deprecated in C++20.

clang/docs/ReleaseNotes.rst

@@ -43,6 +43,10 @@ C/C++ Language Potentially Breaking Changes
 C++ Specific Potentially Breaking Changes
 -----------------------------------------
 
+- The type trait builtin ``__is_nullptr`` has been removed, since it has very
+  few users and can be written as ``__is_same(__remove_cv(T), decltype(nullptr))``,
+  which GCC supports as well.
+
 ABI Changes in This Version
 ---------------------------
 

clang/lib/Parse/ParseDeclCXX.cpp

@@ -447,7 +447,7 @@ Decl *Parser::ParseLinkage(ParsingDeclSpec &DS, DeclaratorContext Context) {
 ///
 /// HLSL: Parse export function declaration.
 ///
-///      export-function-declaration: 
+///      export-function-declaration:
 ///         'export' function-declaration
 /// 
 ///      export-declaration-group:
@@ -1799,7 +1799,6 @@ void Parser::ParseClassSpecifier(tok::TokenKind TagTokKind,
           tok::kw___is_nothrow_constructible,
           tok::kw___is_nothrow_convertible,
           tok::kw___is_nothrow_destructible,
-          tok::kw___is_nullptr,
           tok::kw___is_object,
           tok::kw___is_pod,
           tok::kw___is_pointer,

clang/lib/Parse/ParseExpr.cpp

@@ -800,7 +800,6 @@ bool Parser::isRevertibleTypeTrait(const IdentifierInfo *II,
     REVERTIBLE_TYPE_TRAIT(__is_nothrow_assignable);
     REVERTIBLE_TYPE_TRAIT(__is_nothrow_constructible);
     REVERTIBLE_TYPE_TRAIT(__is_nothrow_destructible);
-    REVERTIBLE_TYPE_TRAIT(__is_nullptr);
     REVERTIBLE_TYPE_TRAIT(__is_object);
     REVERTIBLE_TYPE_TRAIT(__is_pod);
     REVERTIBLE_TYPE_TRAIT(__is_pointer);

clang/lib/Sema/SemaExprCXX.cpp

@@ -4979,7 +4979,6 @@ static bool CheckUnaryTypeTraitTypeCompleteness(Sema &S, TypeTrait UTT,
   case UTT_IsArray:
   case UTT_IsBoundedArray:
   case UTT_IsPointer:
-  case UTT_IsNullPointer:
   case UTT_IsReferenceable:
   case UTT_IsLvalueReference:
   case UTT_IsRvalueReference:
@@ -5238,8 +5237,6 @@ static bool EvaluateUnaryTypeTrait(Sema &Self, TypeTrait UTT,
     return T->isIncompleteArrayType();
   case UTT_IsPointer:
     return T->isAnyPointerType();
-  case UTT_IsNullPointer:
-    return T->isNullPtrType();
   case UTT_IsLvalueReference:
     return T->isLValueReferenceType();
   case UTT_IsRvalueReference:

clang/test/SemaCXX/type-traits.cpp

@@ -1041,42 +1041,6 @@ void is_pointer()
   static_assert(!__is_pointer(void (StructWithMembers::*) ()));
 }
 
-void is_null_pointer() {
-  StructWithMembers x;
-
-  static_assert(__is_nullptr(decltype(nullptr)));
-  static_assert(!__is_nullptr(void *));
-  static_assert(!__is_nullptr(cvoid *));
-  static_assert(!__is_nullptr(cvoid *));
-  static_assert(!__is_nullptr(char *));
-  static_assert(!__is_nullptr(int *));
-  static_assert(!__is_nullptr(int **));
-  static_assert(!__is_nullptr(ClassType *));
-  static_assert(!__is_nullptr(Derives *));
-  static_assert(!__is_nullptr(Enum *));
-  static_assert(!__is_nullptr(IntArNB *));
-  static_assert(!__is_nullptr(Union *));
-  static_assert(!__is_nullptr(UnionAr *));
-  static_assert(!__is_nullptr(StructWithMembers *));
-  static_assert(!__is_nullptr(void (*)()));
-
-  static_assert(!__is_nullptr(void));
-  static_assert(!__is_nullptr(cvoid));
-  static_assert(!__is_nullptr(cvoid));
-  static_assert(!__is_nullptr(char));
-  static_assert(!__is_nullptr(int));
-  static_assert(!__is_nullptr(int));
-  static_assert(!__is_nullptr(ClassType));
-  static_assert(!__is_nullptr(Derives));
-  static_assert(!__is_nullptr(Enum));
-  static_assert(!__is_nullptr(IntArNB));
-  static_assert(!__is_nullptr(Union));
-  static_assert(!__is_nullptr(UnionAr));
-  static_assert(!__is_nullptr(StructWithMembers));
-  static_assert(!__is_nullptr(int StructWithMembers::*));
-  static_assert(!__is_nullptr(void(StructWithMembers::*)()));
-}
-
 void is_member_object_pointer()
 {
   StructWithMembers x;