Implicit parameters cause strange behavi

ghc-5.00.1 (with glasgow-exts) compiles the following
program:

> foo :: ((?x :: Int) => b) -> Int -> b
> foo s z = s with ?x = z
> main = foo (print ?x) 42

Running the generated code prints nothing. (No output
is produced
even if we add putStr "Hello world\n" before the call
to foo).

Trac metadata

Trac field	Value
Version	5.0
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	ResolvedFixed
Component	Compiler
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