replace definition of error with errorWithStackTrace

Mark Wotton mwotton at
Mon Dec 1 04:09:17 UTC 2014

having just spent a day tracking down a really uninformative error in
Cabal, I'm all for this.

On Mon Dec 01 2014 at 11:08:35 Carter Schonwald <carter.schonwald at>

> has been in GHC for for >=1 major version,
> and for normal builds, acts just like error, BUT, when an error is thrown
> in a profiled build, it appends a stack trace with some basic source
> location data to the end of the error message!
> I think this change would benefit many!
> My current understanding is that the DWARF based approach to stack traces
> wont make it into  GHC 7.10 , and while this variant would only provide
> extra info in profiling builds (and strictly less than the dwarf work), its
> something that can definitely be done in a single small patch that could
> easily be swapped out for that improved approach once it lands.
> discussion period: 2 weeks unless theres a clear unanimous agreement to
> make the change ASAP, OR if the stack trace error stuff is landing in 7.10
> and I'm misinformed!
> cheers
> -Carter
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