splitAt does not implement H98 report behaviour, it is too strict in 'n'

The H98 report defines splitAt by:

splitAt :: Int -> [a] -> ([a],[a])
splitAt n xs = (take n xs, drop n xs)

So we would expect:

splitAt _|_ xs = (take _|_ xs, drop _|_ xs)

however GHC's implementation is strict in 'n', that is:

split _|_ xs = _|_

These cases can be distinguished with the expression:

case splitAt undefined [] of (_,_) -> ()

Hugs has the same problem. It defines splitAt by:

splitAt n xs | n <= 0 = ([],xs)
splitAt _ []          = ([],[])
splitAt n (x:xs)      = (x:xs',xs'') where (xs',xs'') = splitAt (n-1) xs

Perhaps for Haskell' we should make the report a little more lenient?

Trac metadata

Trac field	Value
Version	6.6
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	libraries/haskell98
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Operating system	Multiple
Architecture	Multiple