patch applied (ghc): Fix a bug in alternative layout rule

[Simon Marlow]

On 27/11/2009 15:00, Ian Lynagh wrote:
> On Fri, Nov 27, 2009 at 10:28:52AM +0000, Simon Marlow wrote:
>> On 26/11/2009 11:50, Ian Lynagh wrote:
>>> Wed Nov 25 15:19:01 PST 2009  Ian Lynagh<igloo at earth.li>
>>>     * Fix a bug in alternative layout rule
>>>
>>>       M ./compiler/parser/Lexer.x +1
>>
>> Great that you've implemented this.  Are you planning to do a proposal
>> for Haskell 2011?
>
> If e.g. John doesn't get there first, then yes, assuming we can find a
> definition we're happy with.
>
>> It doesn't particularly bother me that the simpler rule can't handle
>> some of the obscure cases.  What bothers me more is that I'm not sure
>> that the proposed rule is more understandable as a specification.  It is
>> definitely easier to implement, but we need a simple way to explain
>> layout to the programmer.
>
> Yes, I agree. First I want to get to the point where validate goes
> through with the flag enabled by default (currently it compiles a number
> of modules, but then fails due to SrcLoc's thinking tabs are 1 character
> wide), and then we can look at tweaking the rule.

SrcLocs think tabs are 1 character wide?  But surely our error messages 
are column-accurate normally, so how can this be?

Cheers,
	Simon