#11014: re-order GHC type errors for clarity -------------------------------------+------------------------------------- Reporter: elaforge | Owner: elaforge Type: feature request | Status: closed Priority: normal | Milestone: Component: Compiler | Version: 7.11 Resolution: fixed | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect | Unknown/Multiple warning at compile-time | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D1427 Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonpj): Evan, thank you for doing this. I think it's a step forward. I failed to review your patch in a timely way, but I've now had a quick look. Some questions * The Monoid instance of `Report` is suspicious. Do you ''really'' merge two separate reports, combining their important and relevant-bindings stuff? Of course not! Rather, you use it exclusively to combine a degenerate report with only 'important' stuff and another degenerate report with only 'supplementary' stuff. This seems confusing and indirect. Instead of {{{ let report = important given_msg `mappend` relevant_bindings binds_msg }}} why not say {{{ let report = mkReport given_msg binds_msg }}} and drop the suspicious Monoid instance. * It will not have escaped your attention that `TcErrors.Report` and `ErrUtils.ErrDoc` are virtually identical. Could you perhaps just combine them? To get the `errDocContext` you could either (I suppose) start with it empty, and add it; or make `mkReport` monadic (better probably). * I'd love you to do as you suggest and get rid of `errMsgShortString`. * Are you sure you need to filter out empty docs? Can't you just avoid putting empty docs into the [SDoc] in the first place? Thanks! -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11014#comment:7 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler