GHC's error messages are too verbose?

[Simon Marlow]

This reminds me of the (closed) bug report about long error messages:

   http://hackage.haskell.org/trac/ghc/ticket/719

I'm not convinced the original bug is fixed, and it seems somewhat similar to 
Bryan's example, being a do-expression.

Cheers,
	Simon

Simon Peyton-Jones wrote:
> Two thoughts on this error-message thread.
> 
> 1. It'd be easy to add a flag to trim the number of levels of context you get.   It'd mean yet another flag though.
> 
> 2.  Bryan got a rather long chunk of program text. GHC tries to trim the size of program chunks by printing "..." after a certain "depth".  But this depth mechanism isn't working well for Bryan's example.  This should not be at all hard to fix -- it look as it may be to do with do-notation.
> 
> Simon
> 
> | -----Original Message-----
> | From: glasgow-haskell-users-bounces at haskell.org [mailto:glasgow-haskell-users-bounces at haskell.org] On
> | Behalf Of Neil Mitchell
> | Sent: 14 April 2007 11:40
> | To: Bryan O'Sullivan
> | Cc: glasgow-haskell-users at haskell.org
> | Subject: Re: GHC's error messages are too verbose?
> |
> | Hi
> |
> | > I've long wondered why GHC issues such prolix error messages when it
> | > runs into a problem.
> |
> | I am primarily a Hugs user, compiling and running only with GHC once
> | the code works, and only if I really need the speed - which is quite
> | rare. but I've been hacking a project in GHCi recently (requiring
> | template haskell), and I found the GHC error messages way too verbose.
> |
> | > Compilers for other languages seem content with as little as one line of
> | > output per error (which I am not advocating), or a few lines of source
> | > with the problem highlighted, but I rarely see more.  Hugs also tends
> | > towards the terse side, but I've never found this to be a problem.
> |
> | The most important thing in an error message for me is the line
> | number. Next I want to see the type of error - syntax, type, instance
> | etc. Then I want to see just a few lexemes of context so I can find
> | where to start looking. If after all that I didn't figure out where
> | the error was, I'd want more context - but I rarely want it with Hugs.
> |
> | I much prefer the Hugs error messages, although this may be experience
> | with Hugs, rather than an issue with GHC.
> |
> | Thanks
> |
> | Neil
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