Compiler loops indefinitely on Morris-style fixed-point operator

Consider the following programs:

-- program 1.hs
newtype F a = F {unF :: F a -> a}
fix f       = (\x -> f (unF x x)) (F (\x -> f (unF x x)))
fac         = fix (\f -> \n -> if n == 0 then 1 else n * f (n - 1))
main        = return ()

-- program 2: morris2.hs
newtype F a = F {unF :: F a -> a}
fix f       = (\x -> f (unF x x)) (F (\x -> f (unF x x)))
fac         = fix (\f -> \n -> if n == 0 then 1 else n * f (n - 1))
main        = print (fac 2)

The first one compiles just fine; the second however causes GHC to go in an infinite loop:

$ ghc -c morris1.hs
$

$ ghc -c morris2.hs
(loops)

Trac metadata

Trac field	Value
Version	6.4.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	low
Resolution	Unresolved
Component	Compiler (Type checker)
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system	MacOS X
Architecture	powerpc