> > As quite a separate point from above, I may have found a bug: I put a > > (?callstack :: CallStack) constraint on TcEvidence.mkTcTransCo and then > > put the same constraint on TcCanonical.rewriteEqEvidence. GHC complained > > about a redundant constraint on rewriteEqEvidence, and indeed its call > > information wasn't propagated. rewriteEqEvidence uses pattern guards and > > do-notation, but that shouldn't muck with CallStack, should it? I've not > > tried to reproduce this in a smaller test case.
After staring at your bug confusedly for a few minutes, wondering why I couldn't simplify it, I realized that the actual warning I was getting was in *mkTcTransCo*, not rewriteEqEvidence. mkTcTransCo does not in fact use a CallStack (by default) so the redundant constraint warning there would be correct. If I add a call to error, everything seems to check out. Can you confirm? Thanks! Eric _______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs