haskell/vector — pull request #2 by evincarofautumn (2013-10-18 18:41:41+00:00)
Title: Make 'fail' better behaved for pattern match failure.

In particular, this makes `-XMonadComprehensions` work much nicelier:

```
{-# LANGUAGE MonadComprehensions #-}
catMaybes :: Vector (Maybe a) -> Vector a
catMaybes xs = [x | Just x <- xs]
```