> AntC clear.net.nz> writes:
Uh-oh, quoted the wrong example. I mean:
Starting with:
class C a b | a -> b where foo :: a -> b
instance C [a] [a] where foo = id
t11 = \x -> foo [x] -- t11 :: t -> [t]
I then added:
instance C [Char] [Char] where foo = id
> Simon Peyton-Jones microsoft.com> writes:
>
> I've realised that GHC's -XIncoherentInstances flag is,
> I think, over-conservative.
Hi Simon, by coincidence I've just come across a very similar issue with
overlapping instances and FunDeps (following-up some discussion with Oleg,
MartinS, Ed
* Bertram Felgenhauer [2013-07-28
17:57:04+0200]
> Roman Cheplyaka wrote:
> > The documentation for throwTo says:
> >
> > throwTo does not return until the exception has been raised in the
> > target thread. The calling thread can thus be certain that the target
> > thread has received the
Giving good type error messages is tricky!
You get different behaviour for literals because 0 has type (forall a. Num a =>
a), whereas you declared x1 to have type Int. GHC could have additionally said
"Can't find an instance for Num Bool, but it suppresses such errors if there
are more seriou
Roman Cheplyaka wrote:
> The documentation for throwTo says:
>
> throwTo does not return until the exception has been raised in the
> target thread. The calling thread can thus be certain that the target
> thread has received the exception. This is a useful property to know
> when dealing
On Sun, Jul 28, 2013 at 5:35 AM, harry wrote:
> $ ghc-pkg check --package-db=~/cabal
> ghc-pkg: ~/cabal: openFile: does not exist (No such file or directory)
> $ ls ~/cabal
> package.cache
>
Yet another reason to avoid ~... it's (a) only expanded by the shell, and
(b) not reliably expanded even
The documentation for throwTo says:
throwTo does not return until the exception has been raised in the
target thread. The calling thread can thus be certain that the target
thread has received the exception. This is a useful property to know
when dealing with race conditions: eg. if there
harry wrote
> $ ghc-pkg check --package-db=~/cabal
> ghc-pkg: ~/cabal: openFile: does not exist (No such file or directory)
> $ ls ~/cabal
> package.cache
Ah, the ~ seems to have been tripping it up. Thank you.
--
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Albert Y. C. Lai wrote
> On 13-07-25 03:14 PM, harry wrote:
>> How can I change the location that ghc and ghc-pkg use for the user's
>> package
>> directory? I'm running GHC in a very restricted environment where I don't
>> have access to $HOME, but I can use specific subdirectories.
>
> Cannot. B
