As I guessed, `@executable` can be `BlockEnvironment::AsMethod` along side `CompiledCode`. I fixed that at [my branch](https://github.com/ryoqun/rubinius/tree/unbound-method-parameters) based on your branch with this [commit](https://github.com/ryoqun/rubinius/commit/83c6f8d9b15e134f118adf2814ca21b250bcbd77).

Could you `rebase --interactive` this, while unifying it into your refactoring commit?