#5325: The -dsuppress-type-signatures flag behaves wrongly on RULES
---------------------------------+------------------------------------------
Reporter: reinerp | Owner:
Type: bug | Status: new
Priority: normal | Component: Compiler
Version: 7.0.3 | Keywords:
Testcase: | Blockedby:
Os: Unknown/Multiple | Blocking:
Architecture: Unknown/Multiple | Failure: None/Unknown
---------------------------------+------------------------------------------
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.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5325>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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