Why toInteger :: Int -> Integer is lazy?

Posted by joppux on Stack Overflow See other posts from Stack Overflow or by joppux
Published on 2010-05-01T12:57:43Z Indexed on 2010/05/01 13:07 UTC
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Filed under:

haskell

|

laziness

I have the following code:

{-# NOINLINE i2i #-}
i2i :: Int -> Integer
i2i x = toInteger x

main = print $ i2i 2

Running GHC with -ddump-simpl flag gives:

[Arity 1
 NoCafRefs
 Str: DmdType U(L)]
Main.i2i = GHC.Real.toInteger1

Seems that conversion from Int to Integer is lazy. Why is it so - is there a case when I can have

(toInteger _|_ ::Int) /= _|_

?

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