Merge pull request #2344 from yui-knk/fix-locals

Change to always use locals->car->car.

src/parse.y

@@ -253,7 +253,11 @@ local_var_p(parser_state *p, mrb_sym sym)
 static void
 local_add_f(parser_state *p, mrb_sym sym)
 {
-  p->locals->car = push(p->locals->car, nsym(sym));
+  if (p->locals->car && !p->locals->car->car) {
+    p->locals->car->car = nsym(sym);
+  } else {
+    p->locals->car = push(p->locals->car, nsym(sym));
+  }
 }
 
 static void