GHC 7.10 regression when using foldr
malcolm.wallace at me.com
Tue Jan 20 11:43:30 UTC 2015
On 20 Jan 2015, at 11:20, Björn Peemöller wrote:
> The reason is the usage of foldr, which changed its type from
> foldr :: (a -> b -> b) -> b -> [a] -> b -- GHC 7.8.4
> foldr :: Foldable t => (a -> b -> b) -> b -> t a -> b -- GHC 7.10.1
> Thus, the use of foldr is now ambiguous. I can fix this by providing a
> type signature
> convert :: ([a], String) -> (List a, String)
> However, is this breaking change intended?
I believe this kind of breakage was predicted by those opposed to the change of signature. That is not quite the same thing as being intended or desired.
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