Call Arity has the trivial application case wrong

In e x, the result of x is not shared in contrast to e (f x), where CorePrep will turn it into let y = f x in e x. So in

  let f = ...
  in e (f x)

we know that f is called at most once, but in

  let f = ...
  in e f

we do not know that.

Previously Call Arity would assume that in e x, x is evaluated at most once. This rarely would make a difference (the argument x is analized with an incoming arity of 0, so no eta-expansion would be done anyways), but of course this should still be fixed.

I just validated a patch and will push shortly.

Trac metadata

Trac field	Value
Version	7.10.2
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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