diff --git a/science/step/files/patch-stepcore_object.h b/science/step/files/patch-stepcore_object.h
new file mode 100644
index 000000000000..5b2f47415a27
--- /dev/null
+++ b/science/step/files/patch-stepcore_object.h
@@ -0,0 +1,21 @@
+Clang >= 19.1.0-rc1 requires a template argument list after an identifier
+prefixed by the template keyword. [1]
+
+/wrkdirs/usr/ports/science/step/work/step-23.08.5/stepcore/object.h:252:45:
+error: a template argument list is expected after a name prefixed by the
+template keyword [-Wmissing-template-arg-list-after-template-kw]
+  252 |     if(!src || !src->metaObject()->template inherits(_Dst())) return NULL;
+
+[1] https://github.com/llvm/llvm-project/commit/f46d1463b835560d90ad3ac02b63c771e4ebe566
+
+--- stepcore/object.h.orig	2024-02-10 03:35:30 UTC
++++ stepcore/object.h
+@@ -249,7 +249,7 @@ _Dst stepcore_cast(_Src src) {
+ /** Casts between pointers to Object */
+ template<class _Dst, class _Src> // XXX: implement it better
+ _Dst stepcore_cast(_Src src) {
+-    if(!src || !src->metaObject()->template inherits(_Dst())) return NULL;
++    if(!src || !src->metaObject()->template inherits<_Dst>(_Dst())) return NULL;
+     return static_cast<_Dst>(src);
+ }
+