diff --git a/include/mruby/object.h b/include/mruby/object.h
index 912a4a225..246d7552a 100644
--- a/include/mruby/object.h
+++ b/include/mruby/object.h
@@ -23,10 +23,9 @@ struct RBasic {
 #define mrb_basic_ptr(v) ((struct RBasic*)(mrb_ptr(v)))
 
 #define MRB_OBJ_IS_FROZEN 1
-#define MRB_FROZEN_P(o) ((o)->frozen)
+#define mrb_frozen_p(o) ((o)->frozen)
 #define MRB_SET_FROZEN_FLAG(o) ((o)->frozen = 1)
 #define MRB_UNSET_FROZEN_FLAG(o) ((o)->frozen = 0)
-#define mrb_frozen_p(o) MRB_FROZEN_P(o)
 
 struct RObject {
   MRB_OBJECT_HEADER;
diff --git a/src/class.c b/src/class.c
index 40f1ff171..aa16cfb23 100644
--- a/src/class.c
+++ b/src/class.c
@@ -768,7 +768,7 @@ mrb_define_method_raw(mrb_state *mrb, struct RClass *c, mrb_sym mid, mrb_method_
         }
       }
       else {
-        mrb_assert(MRB_FROZEN_P(p) && MRB_PROC_SCOPE_P(p));
+        mrb_assert(mrb_frozen_p(p) && MRB_PROC_SCOPE_P(p));
         mrb_assert(p->c == NULL && p->upper == NULL && p->e.target_class == NULL);
       }
     }
diff --git a/src/hash.c b/src/hash.c
index d4268d33c..54f2dfa00 100644
--- a/src/hash.c
+++ b/src/hash.c
@@ -987,7 +987,7 @@ ht_rehash(mrb_state *mrb, struct RHash *h)
 static mrb_value
 h_key_for(mrb_state *mrb, mrb_value key)
 {
-  if (mrb_string_p(key) && !MRB_FROZEN_P(mrb_str_ptr(key))) {
+  if (mrb_string_p(key) && !mrb_frozen_p(mrb_str_ptr(key))) {
     key = mrb_str_dup(mrb, key);
     MRB_SET_FROZEN_FLAG(mrb_str_ptr(key));
   }