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SpecConstr doesn't specialise

Compile this with -O2 -fno-spec-constr-count:

foo :: Int -> Int -> Bool
foo n x = loop 0 False (Just x)
  where
    loop i b x | i > n = b
    loop i False x = loop (i+1) True x
    loop i True (Just x) = loop (i+1) False Nothing
    loop i True Nothing  = loop (i+1) True (Just x)

!SpecConstr produces a loop of type Maybe Int -> Int# -> Bool, i.e., it doesn't specialise for the Maybe argument for some reason.

Trac metadata
Trac field Value
Version 7.1
Type Bug
TypeOfFailure OtherFailure
Priority normal
Resolution Unresolved
Component Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture
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