#2224: -fhpc inteferes/prevents rewrite rules from firing
------------------------------+---------------------------------------------
Reporter: dons | Owner: [EMAIL PROTECTED]
Type: bug | Status: new
Priority: normal | Milestone:
Component: Code Coverage | Version: 6.8.2
Severity: normal | Resolution:
Keywords: rules, hpc | Testcase:
Architecture: Unknown | Os: Unknown
------------------------------+---------------------------------------------
Comment (by AndyGill):
I'm not sure what to do here. To match code that contains ticks, and
rewrite them requires either
* removing ticks - generally a bad idea!
* recreating the ticks, which is hard/impossible to do in some cases.
I suppose we could have an option to ignore ticks in rules, but this leads
to false positives.
Also consider:
{{{
{-# RULES
"pack/packAddress" forall s . pack (unpackCString# s) = B.packAddress
s
#-}
}}}
pack and unpackCString are strict, so we have tick equivalence!
{{{
tick<1>pack(tick<2>unpackCString# (tick<3> s))
}}}
is the same as
{{{
tick<1,2,3>pack(unpackCString# s)
}}}
The tick lifting has given us the original match.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2224#comment:1>
GHC <http://www.haskell.org/ghc/>
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