diff --git a/py/obj.h b/py/obj.h
index ea3d2db706..c94d09afab 100644
--- a/py/obj.h
+++ b/py/obj.h
@@ -750,12 +750,12 @@ void *mp_obj_malloc_helper(size_t num_bytes, const mp_obj_type_t *type);
 // Type checks are split to a separate, constant result macro. This is so it doesn't hinder the compilers's
 // optimizations (other tricks like using ({ expr; exper; }) or (exp, expr, expr) in mp_obj_is_type() result
 // in missed optimizations)
-#define mp_type_assert_not_bool_int_str_nonetype(t) (         \
-     MP_STATIC_ASSERT_NOT_MSC((t) != &mp_type_bool),          \
-     MP_STATIC_ASSERT_NOT_MSC((t) != &mp_type_int),           \
-     MP_STATIC_ASSERT_NOT_MSC((t) != &mp_type_str),           \
-     MP_STATIC_ASSERT_NOT_MSC((t) != &mp_type_NoneType),      \
-     1)
+#define mp_type_assert_not_bool_int_str_nonetype(t) (                                     \
+    MP_STATIC_ASSERT_NOT_MSC((t) != &mp_type_bool), assert((t) != &mp_type_bool),         \
+    MP_STATIC_ASSERT_NOT_MSC((t) != &mp_type_int), assert((t) != &mp_type_int),           \
+    MP_STATIC_ASSERT_NOT_MSC((t) != &mp_type_str), assert((t) != &mp_type_str),           \
+    MP_STATIC_ASSERT_NOT_MSC((t) != &mp_type_NoneType), assert((t) != &mp_type_NoneType), \
+    1)
 
 #define mp_obj_is_type(o, t) (mp_type_assert_not_bool_int_str_nonetype(t) && mp_obj_is_exact_type(o, t))
 #if MICROPY_OBJ_IMMEDIATE_OBJS