define Module#const_missing

src/class.c

@@ -1833,6 +1833,18 @@ mrb_mod_remove_const(mrb_state *mrb, mrb_value mod)
   return val;
 }
 
+mrb_value
+mrb_mod_const_missing(mrb_state *mrb, mrb_value mod)
+{
+  mrb_sym sym;
+
+  mrb_get_args(mrb, "n", &sym);
+  mrb_name_error(mrb, sym, "uninitialized constant %S",
+                 mrb_sym2str(mrb, sym));
+  /* not reached */
+  return mrb_nil_value();
+}
+
 static mrb_value
 mrb_mod_s_constants(mrb_state *mrb, mrb_value mod)
 {
@@ -1926,6 +1938,7 @@ mrb_init_class(mrb_state *mrb)
   mrb_define_method(mrb, mod, "const_set",               mrb_mod_const_set,        MRB_ARGS_REQ(2)); /* 15.2.2.4.23 */
   mrb_define_method(mrb, mod, "constants",               mrb_mod_constants,        MRB_ARGS_NONE()); /* 15.2.2.4.24 */
   mrb_define_method(mrb, mod, "remove_const",            mrb_mod_remove_const,     MRB_ARGS_REQ(1)); /* 15.2.2.4.40 */
+  mrb_define_method(mrb, mod, "const_missing",           mrb_mod_const_missing,    MRB_ARGS_REQ(1));
   mrb_define_method(mrb, mod, "define_method",           mod_define_method,        MRB_ARGS_REQ(1));
   mrb_define_method(mrb, mod, "class_variables",         mrb_mod_class_variables,  MRB_ARGS_NONE()); /* 15.2.2.4.19 */
   mrb_define_method(mrb, mod, "===",                     mrb_mod_eqq,              MRB_ARGS_REQ(1));

src/variable.c

@@ -867,7 +867,7 @@ const_get(mrb_state *mrb, struct RClass *base, mrb_sym sym)
   mrb_value v;
   iv_tbl *t;
   mrb_bool retry = 0;
-  mrb_sym cm;
+  mrb_value name;
 
 L_RETRY:
   while (c) {
@@ -883,19 +883,8 @@ L_RETRY:
     retry = 1;
     goto L_RETRY;
   }
-  c = base;
-  cm = mrb_intern2(mrb, "const_missing", 13);
-  while (c) {
-    if (mrb_respond_to(mrb, mrb_obj_value(c), cm)) {
-      mrb_value name = mrb_symbol_value(sym);
-      return mrb_funcall_argv(mrb, mrb_obj_value(c), cm, 1, &name);
-    }
-    c = c->super;
-  }
-  mrb_name_error(mrb, sym, "uninitialized constant %S",
-             mrb_sym2str(mrb, sym));
-  /* not reached */
-  return mrb_nil_value();
+  name = mrb_symbol_value(sym);
+  return mrb_funcall_argv(mrb, mrb_obj_value(base), mrb_intern2(mrb, "const_missing", 13), 1, &name);
 }
 
 mrb_value