diff --git a/ChangeLog b/ChangeLog
index ab38e6c1f2..c679d4a63f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Fri Oct 28 15:58:16 2016  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* internal.h (RB_OBJ_BUILTIN_TYPE): special-const safe
+	  BUILTIN_TYPE.
+
 Fri Oct 28 15:20:18 2016  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* complex.c (id_finite_p, id_infinite_p, id_rationalize, id_PI):
diff --git a/ext/objspace/objspace.c b/ext/objspace/objspace.c
index eff9d0c7f8..958ef71db2 100644
--- a/ext/objspace/objspace.c
+++ b/ext/objspace/objspace.c
@@ -922,7 +922,7 @@ objspace_internal_super_of(VALUE self, VALUE obj)
 	obj = (VALUE)DATA_PTR(obj);
     }
 
-    switch (TYPE(obj)) {
+    switch (OBJ_BUILTIN_TYPE(obj)) {
       case T_MODULE:
       case T_CLASS:
       case T_ICLASS:
diff --git a/file.c b/file.c
index 76162b0856..fbf13113e8 100644
--- a/file.c
+++ b/file.c
@@ -4346,7 +4346,7 @@ rb_file_join(VALUE ary, VALUE sep)
     OBJ_INFECT(result, ary);
     for (i=0; i<RARRAY_LEN(ary); i++) {
 	tmp = RARRAY_AREF(ary, i);
-	switch (TYPE(tmp)) {
+	switch (OBJ_BUILTIN_TYPE(tmp)) {
 	  case T_STRING:
 	    if (!checked) check_path_encoding(tmp);
 	    StringValueCStr(tmp);
diff --git a/internal.h b/internal.h
index 116654ef91..c7e80aa978 100644
--- a/internal.h
+++ b/internal.h
@@ -1682,6 +1682,24 @@ do { \
     } \
 } while (0)
 
+#define RB_OBJ_BUILTIN_TYPE(obj) rb_obj_builtin_type(obj)
+#define OBJ_BUILTIN_TYPE(obj) RB_OBJ_BUILTIN_TYPE(obj)
+#ifdef __GNUC__
+#define rb_obj_builtin_type(obj) \
+__extension__({ \
+    VALUE arg_obj = (obj); \
+    RB_SPECIAL_CONST_P(arg_obj) ? -1 : \
+	RB_BUILTIN_TYPE(arg_obj); \
+    })
+#else
+static inline int
+rb_obj_builtin_type(VALUE obj)
+{
+    return RB_SPECIAL_CONST_P(obj) ? -1 :
+	RB_BUILTIN_TYPE(obj);
+}
+#endif
+
 #if defined(__cplusplus)
 #if 0
 { /* satisfy cc-mode */