Dear Sir,
playing with Hugs I have found a strange behavior that could be the
symptom of a bug. Please note that I am using the last version of Hugs
(February 2000) with the type checker fix suggested in the bug page.
If I define the function
f x = x + x
and then ask Hugs to report the type, I get a very reasonable answer:
f :: Num a => a -> a
The same happens if I directly ask the type of the lambda abstraction
\x -> x + x. In other words, the command
> :type \x -> x + x
gives the answer
\x -> x + x :: Num a => a -> a
If now I define
g = \x -> x + x
I get the surprising type
g :: Integer -> Integer
Analogously, using "g 2.5" produces the error
*** Expression : g 2.5
*** Type : Fractional Integer => Integer
Is this normal or is really a bug? Please note that the Glasgow
Haskell Compiler seems to identify the correct type for both f and g.
Best regards,
Marco Lombardi
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Marco Lombardi
Scuola Normale Superiore European Southern Observatory
P.zza dei Cavalieri 7 Karl-Schwarzschild-Str. 2
I-56100, Pisa, Italy D-85748, Garching, Germany
tel.: +39-050-509111 tel.: +49-(0)89-32006362
fax: +39-050-563513 fax: +49-(0)89-3202362
e-mail: [EMAIL PROTECTED] e-mail: [EMAIL PROTECTED]
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