Re: [Haskell-cafe] bug in ghci ?

Hehe, seems like a -W-mutual-recursive-default-methods option is in order. On 8 July 2010 15:47, Ivan Lazar Miljenovic wrote:

"Pasqualino \"Titto\" Assini" writes:

...

Thanks for the explanation.

What I meant is not that is a bug that it recurses but rather the fact that the compiler will accept this incomplete definition without complaining.

This problem has bitten me twice while trying to use automatic derivation of a data type in another file.

In my innocence I wrote:

instance Show Test

rather than

deriving  instance Show Test

I didn't notice the error as GHC seemed to be happy and then when I tried to use it: BANG!

Very confusing.

I suppose that Haskell has spoiled me, if it compiles I assume that it will work :-)

As I said, there would be no error as all the methods have a definition (whether or not they make sense in this case is a different story); it will still successfully load a file if any methods don't have definitions but will provide a warning in those situations.

-- Ivan Lazar Miljenovic Ivan.Miljenovic@gmail.com IvanMiljenovic.wordpress.com _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe