So, it looks like it is hugs which is not following the report (section 4.5.5 (rule 2) as Iavor noted), which seems to indicate that defaulting only occurs after an entire module is type-checked. - Mark Begin forwarded message:

From: "Iavor S. Diatchki" <diatchki@cse.ogi.edu> Date: Thu Oct 23, 2003 3:07:45 PM US/Pacific To: Mark Tullsen <tullsen@galois.com> Cc: haskell@haskell.org Subject: Re: when is defaulting supposed to occur?

hello, the problem has to do with the monomorphism restriction see section 4.5.5 (rule 2) (or typing hashell in haskell section 11.5.1 for details). bye iavor

Mark Tullsen wrote:

...

Note the following program x = 1 y = x :: Int

This is accepted by ghc but it is rejected hugs (May 2003 cvs): ERROR "IntegerTest.hs":4 - Type error in type annotation *** Term : x *** Type : Integer *** Does not match : Int

My guess is that hugs is doing defaulting after a "declaration group" is type-checked, but that ghci leaves 'x' with type 'Num a', then processes further declaration groups, and then does defaulting.

I don't see that the report specifies this (did I miss it?).

- Mark

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-- ================================================== | Iavor S. Diatchki, Ph.D. student | | Department of Computer Science and Engineering | | School of OGI at OHSU | | http://www.cse.ogi.edu/~diatchki | ==================================================