#1292: -fwarn-monomorphism-restriction should be -Wmonomorphism-restriction
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Reporter: guest | Owner:
Type: bug | Status: closed
Priority: normal | Milestone:
Component: Compiler | Version: 6.7
Severity: normal | Resolution: invalid
Keywords: | Difficulty: Unknown
Os: Unknown | Testcase:
Architecture: Unknown |
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Comment (by igloo):
(Can you please not close bugs without comment or anonymously? Thanks)
On the name of the flag, `-fwarn` rather than `-W` seems to be the naming
convention.
However, on having the warning on by default:
We've seen a number of failures in the HEAD+extralibs build because of
this warning,
e.g. a warning about `index` in the below snippet from regex-compat:
{{{
else let index = (read (head bgroups)) - 1
in
if index == -1
then match
else groups !! index
}}}
Here, and I imagine everywhere (non-contrived) that compilation succeeds,
monomorphism is exactly what we want. As I believe it is a good policy to
keep code `-Wall` clean, I personally would not like this warning to be
enabled even by `-Wall`. Debatably it would be good style to add a type
signature for `index`, though.
The warning may be useful for people investigating removing or replacing
the MR, but they can enable it themselves.
It may also be useful to show any such warnings when compilation fails,
but that feels like a bit of a hack and may result in a flood of unrelated
warnings when a single error occurs.
I've turned the warning off for now, so at least it won't break the
nightly builds.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1292>
GHC <http://www.haskell.org/ghc/>
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