On 11.06.2015 18:20, Dan Doel wrote: > I believe a pattern is classified as unfailable there if it is irrefutable or > refutable only by bottom. Which of course is the distinction here, (x,y) is > unfailable, but not irrefutable.
Some of the confusion may be because GHC has a function "isIrrefutableHsPat" that seems to check whether a pattern is irrefutable by your definition. The source comment talks about naming a bit: > (isIrrefutableHsPat p) is true if matching against p cannot fail, > in the sense of falling through to the next pattern. > (NB: this is not quite the same as the (silly) defn > in 3.17.2 of the Haskell 98 report.) Source: https://github.com/ghc/ghc/blob/c5911479f295242e16e396eb5d1369f2e4ce8de0/compiler/hsSyn/HsPat.hs#L443 (Time for a PatternUnfallthroughableProposal?) Greetings, David _______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs
