[nhc-bugs] the format of error diagnostics

[Malcolm Wallace]

> nhc98 would be much more convenient to use if the error diagnostics were
> compatible with Emacs compile mode.

I would like to make that possible, but I'm not sure exactly how it
would work.  For instance you suggest

>    nhc98    -c -d ../nhc Flatten.hs
>    
>    ====================================
>    	Error when renaming::
>    Constructor OK used at 833:6 is not defined.

should be more like

>    Flatten.hs:833:6: Error when renaming::
>    Constructor OK is not defined.

But what should the following kind of report translate to?

   	Error when renaming::
   Constructor OK used at 117:30, 103:15, 98:21, 72:13, 35:5 is not defined.
   Identifier splitWhile used at 110:13, 106:8, 102:8, 91:13 is not defined.
   Identifier digit used at 272:52, 259:52 is not defined.

Do you want a separate line for each?  And how about this one:

	Error after type deriving/checking:
   Type error type clash between Prelude.Int and Main.Foo
   when trying to apply function at 4:17 to its 1:st argument at 4:8.

A type error is always found as a mismatch between two expressions,
leading to at least two possible positions.  Which position should
the type error be reported for?

Regards,
    Malcolm