在qmake和mingw32-make之后,these指令成功,
并且我执行runhaskell Setup.hs build,我收到以下错误：
并且我执行runhaskell Setup.hs build,我收到以下错误：
[651 of 662] Compiling Qtc.Core.Attributes ( Qtc\Core\Attributes.hs,dist\build\Qtc\Core\Attributes.o )
Qtc\Core\Attributes.hs:584:13:
Could not deduce (Qstt a (QDialogSc b))
arising from a use of `slotReject''
from the context (Qstt a (QDialogSc b1))
bound by the instance declaration
at Qtc\Core\Attributes.hs:582:10-52
Possible fix:
add (Qstt a (QDialogSc b)) to the context of
the instance declaration
or add an instance declaration for (Qstt a (QDialogSc b))
In the expression: slotReject'
In an equation for `reject'': reject' = slotReject'
In the instance declaration for `QsaSlotReject a'
Attributes.hs文件(第578 – 583行)：
class QsaSlotReject w where slotReject',reject' :: (Qslot w (w -> ()),(w -> ())) instance (Qstt a (QDialogSc b)) => QsaSlotReject (a) where slotReject' = (Qslot "reject()",\_ -> ()) reject' = slotReject'
环境 ：
> Windows 7
> Haskell平台2011.2.0
> Qt sdk 4.7
顺便说一句,我在这个过程中遇到了两次内存不足,但我猜这没关系.
麻烦来自于这个事实
data Qslot x f = Qslot String
因此,从Qslot“Blah blah”形式的给定项目推断x和f可能有点困难.自从去年秋天qthaskell的最后一个版本上升以来,GHC使用的推理机制可能发生了微妙的变化.
在任何情况下,它似乎编译,带有一些好奇的警告,并且示例工作,如果你替换
instance (Qstt a (QDialogSc b)) => QsaSlotReject (a) where
slotReject' = (Qslot "reject()",\_ -> ())
reject' = slotReject'
同
instance (Qstt a (QDialogSc b)) => QsaSlotReject (a) where slotReject' = (Qslot "reject()",\_ -> ()) reject' = (Qslot "reject()",\_ -> ())
那样ghc就不用多想了……
必须有一些东西可以使事情更精确.我不知道eta减少警告是否会在以后系统地开始出现,这与此线路有关.
