diff --git a/ggml-metal.m b/ggml-metal.m
index 90bbdffd8..88ea98215 100644
--- a/ggml-metal.m
+++ b/ggml-metal.m
@@ -2093,7 +2093,7 @@ void ggml_backend_metal_set_n_cb(ggml_backend_t backend, int n_cb) {
 }
 
 bool ggml_backend_metal_supports_family(ggml_backend_t backend, int family) {
-    GGML_UNUSED(ggml_backend_is_metal(backend));
+    GGML_ASSERT(ggml_backend_is_metal(backend));
 
     struct ggml_metal_context * ctx = (struct ggml_metal_context *)backend->context;