Missing ShadowedName cases

``` purescript
test :: forall m. Monad m => Int -> m Int
test x =
  let x = 0
  in pure x
```

``` purescript
test :: forall m. Monad m => Int -> m Int
test x = do
  x <- pure x
  pure x
```

I did check these with what's in `master` this time :wink:
