Comment delimiters ignored inside compiler pragma

[heatsink]

GHC accepts some pragmas that are not valid comments because of embedded comment delimiters. If the delimiters are hidden inside an embedded comment or string, they are not recognized by the parser, but they should be according to the Haskell report. For example, the following has one opening and three closing comment delimiters, but is accepted by the parser.

{-# RULES
 "-}" id 0 = 0
 -- -}
 #-}

[igloo]

Hmm, personally I would say the language definition ought to have {-# and #-} as lexemes.

[igloo]

Actually, having thought about it more, I think you are right and it is just a straight GHC bug.

[simonmar]

Good point, but awkward to fix, and unlikely to be a problem often in practice.