Unusable {-# UNPACK #-} pragmas.

[chowells79]

[2 of 4] Compiling Text.Earley.Parser ( Text/Earley/Parser.hs, dist/build/Text/Earley/Parser.o )

Text/Earley/Parser.hs:83:3: Warning:
    Ignoring unusable UNPACK pragma on the third argument of ‘State’
    In the definition of data constructor ‘State’
    In the data declaration for ‘State’

Text/Earley/Parser.hs:92:3: Warning:
    Ignoring unusable UNPACK pragma on the second argument of ‘Cont’
    In the definition of data constructor ‘Cont’
    In the data declaration for ‘Cont’

Text/Earley/Parser.hs:92:3: Warning:
    Ignoring unusable UNPACK pragma on the fourth argument of ‘Cont’
    In the definition of data constructor ‘Cont’
    In the data declaration for ‘Cont’

In all cases, those arguments are Arg values, and Arg is a type alias for a function type. Function types can't be unpacked, since they aren't thin wrappers around primitives.

[ollef]

Thanks for your report.

You're right. In fact, I just realised that the cabal file gives the -funbox-strict-fields flag so all UNPACKs could probably be removed. Out of interest, what version of GHC are you using? I'm not getting those warnings even with -Wall running 7.10.1.

[ollef]

Fixed by 6fc5388.

[chowells79]

GHC 7.10.1, just building with cabal. Not sure why I got the warnings and you didn't.