scrooloose/nerdcommenter — pull request #96 by fengshaun (2012-11-27 00:51:57+00:00)
Title: Haskell's multi-line/sexy commenting acts unpredictably, now fixed.

the leftAlt (for multi-line commenting) should be '{- ', not '-- '. -- is used for single line commenting while {- and -} are used for multiline commenting. This was mixed up in the latest version. It is fixed now and works properly as far as I have tested it.