id,summary,reporter,owner,description,type,status,priority,milestone,component,version,resolution,keywords,cc,os,architecture,failure,difficulty,testcase,blockedby,blocking,related
5325,The -dsuppress-type-signatures flag behaves wrongly on RULES,reinerp,igloo,"Given this module:

{{{
module M where

f :: Num a => a -> a
f x = x + 1

{-# SPECIALISE f :: Int -> Int #-}
}}}

if we compile with


{{{
ghc -dsuppress-type-signatures -O -ddump-simpl M.hs
}}}

we see that the SPECIALISE pragma has become the following:


{{{
""SPEC M.f"" [ALWAYS] forall {} M.f @ GHC.Types.Int $dNum_anE = M.f_f
}}}

It looks dNum_anE is a free variable in this rule, but it's actually a bound variable, as we can see when we compile without -dsuppress-type-signatures:


{{{
""SPEC M.f"" [ALWAYS]
    forall {$dNum_anE :: GHC.Num.Num GHC.Types.Int}
      M.f @ GHC.Types.Int $dNum_anE
      = M.f_f
}}}

I think GHC should produce the following output with -dsuppress-type-signatures:


{{{
""SPEC M.f"" [ALWAYS] forall {$dNum_anE} M.f @ GHC.Types.Int $dNum_anE = M.f_f
}}}

This is with GHC 7.1.20110629.",bug,closed,normal,7.4.1,Compiler,7.0.3,fixed,,,Unknown/Multiple,Unknown/Multiple,None/Unknown,,,,,