4 files changed, 26 insertions, 1 deletions
diff --git a/compilerplugins/clang/check.cxx b/compilerplugins/clang/check.cxx
index 4ff081b6923e..60e476cc37b7 100644
--- a/compilerplugins/clang/check.cxx
+++ b/compilerplugins/clang/check.cxx
@@ -133,6 +133,16 @@ TypeCheck TypeCheck::Pointer() const {
     return TypeCheck();
 }
 
+TypeCheck TypeCheck::MemberPointerOf() const {
+    if (!type_.isNull()) {
+        auto const t = type_->getAs<clang::MemberPointerType>();
+        if (t != nullptr) {
+            return TypeCheck(t->getClass());
+        }
+    }
+    return TypeCheck();
+}
+
 TerminalCheck TypeCheck::Enum() const {
     if (!type_.isNull()) {
         auto const t = type_->getAs<clang::EnumType>();
diff --git a/compilerplugins/clang/check.hxx b/compilerplugins/clang/check.hxx
index af6cd355a416..65ee16d77f2c 100644
--- a/compilerplugins/clang/check.hxx
+++ b/compilerplugins/clang/check.hxx
@@ -62,6 +62,8 @@ public:
 
     TypeCheck Pointer() const;
 
+    TypeCheck MemberPointerOf() const;
+
     TerminalCheck Enum() const;
 
     TypeCheck LvalueReference() const;
diff --git a/compilerplugins/clang/nullptr.cxx b/compilerplugins/clang/nullptr.cxx
index 0213b6b05c88..04fb5bf0f9fd 100644
--- a/compilerplugins/clang/nullptr.cxx
+++ b/compilerplugins/clang/nullptr.cxx
@@ -131,11 +131,18 @@ bool Nullptr::VisitImplicitCastExpr(CastExpr const * expr) {
     case Expr::NPCK_CXX11_nullptr:
         break;
     default:
-        if (loplugin::TypeCheck(expr->getType()).Typedef("locale_t")
+        auto const tc = loplugin::TypeCheck(expr->getType());
+        if (tc.Typedef("locale_t")
             .GlobalNamespace())
         {
             break; // POSIX locale_t is left unspecified
         }
+        // Hack to handle libc++ and stdlibc++ `std::strong_ordering x; x < 0` etc.:
+        if (tc.MemberPointerOf().ClassOrStruct("_CmpUnspecifiedParam").StdNamespace()
+            || tc.Pointer().ClassOrStruct("__unspec").Namespace("__cmp_cat").StdNamespace())
+        {
+            break;
+        }
         handleNull(expr->getSubExpr(), expr->getCastKindName(), k);
         break;
     }
diff --git a/compilerplugins/clang/test/nullptr.cxx b/compilerplugins/clang/test/nullptr.cxx
index bf7376cb6562..392a930bf9b8 100644
--- a/compilerplugins/clang/test/nullptr.cxx
+++ b/compilerplugins/clang/test/nullptr.cxx
@@ -7,6 +7,10 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+#include "sal/config.h"
+
+#include <compare>
+
 struct S
 {
     void* p;
@@ -18,6 +22,8 @@ int main()
         0 // expected-error {{NullToPointer ValueDependentIsNotNull ZeroLiteral -> nullptr [loplugin:nullptr]}}
     };
     (void)s;
+
+    (void)(std::strong_order(0, 1) < 0);
 }
 
 /* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */