mruby/mruby — pull request #1611 by h2so5 (2013-12-19 08:44:07+00:00)
Title: fix TypeError message

fix incorrect error messages like this:

```
mirb - Embeddable Interactive Ruby Shell

This is a very early version, please test and report errors.
Thanks :)

> 1 << nil
(mirb):1: can't convert into Integer (TypeError)
> 1 << ""
(mirb):1: can't convert into Integer (TypeError)
> 1 << []
(mirb):1: can't convert into Integer (TypeError)
```