compile.c: fix position

* compile.c (iseq_compile_each): vals is NULL here, show the
  position of the parent node.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@52712 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

compile.c

@@ -3713,7 +3713,7 @@ iseq_compile_each(rb_iseq_t *iseq, LINK_ANCHOR *ret, NODE * node, int poped)
 		}
 	    }
 	    else {
-		rb_compile_bug(ERROR_ARGS_AT(vals) "NODE_CASE: must be NODE_ARRAY, but 0");
+		rb_compile_bug(ERROR_ARGS "NODE_CASE: must be NODE_ARRAY, but 0");
 	    }
 
 	    node = node->nd_next;