+1, as I don't see a downside. However, I don't think this change is a sufficient change as long as stack traces are only available for profiled builds. I still wish something like rewrite-with-location[1], which even addresses explicit stack traces directly[2]. IIRC, last time that feature was brought up for discussion, it stalled due to disagreements on the right design. I think we have something of a consensus forming around https://ghc.haskell.org/trac/ghc/wiki/ExplicitCallStack/ImplicitLocations, see #9049. It’s simple, non-invasive, and predicatable. It does need someone to implement it though. Simon Hengel is thinking about implementing it. (He is the one who also suggested “rewrite with location”). So I think we are stalled not so much on design but on implementation. Simon From: Libraries [mailto:libraries-bounces@haskell.org] On Behalf Of Michael Snoyman Sent: 01 December 2014 05:33 To: Christopher Allen; Mark Wotton Cc: Haskell Libraries Subject: Re: replace definition of error with errorWithStackTrace +1, as I don't see a downside. However, I don't think this change is a sufficient change as long as stack traces are only available for profiled builds. I still wish something like rewrite-with-location[1], which even addresses explicit stack traces directly[2]. IIRC, last time that feature was brought up for discussion, it stalled due to disagreements on the right design. [1] https://github.com/sol/rewrite-with-location [2] https://github.com/sol/rewrite-with-location#explicit-call-stacks On Mon Dec 01 2014 at 6:39:25 AM Christopher Allen <cma@bitemyapp.com<mailto:cma@bitemyapp.com>> wrote: +1 - I would be very happy if this happened. On Sun, Nov 30, 2014 at 10:09 PM, Mark Wotton <mwotton@gmail.com<mailto:mwotton@gmail.com>> wrote: 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@gmail.com<mailto:carter.schonwald@gmail.com>> wrote: http://hackage.haskell.org/package/base-4.7.0.1/docs/GHC-Stack.html#v:errorW... 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 _______________________________________________ Libraries mailing list Libraries@haskell.org<mailto:Libraries@haskell.org> http://www.haskell.org/mailman/listinfo/libraries _______________________________________________ Libraries mailing list Libraries@haskell.org<mailto:Libraries@haskell.org> http://www.haskell.org/mailman/listinfo/libraries _______________________________________________ Libraries mailing list Libraries@haskell.org<mailto:Libraries@haskell.org> http://www.haskell.org/mailman/listinfo/libraries