From 802fc606ff18c261eb591d7ae6dbb99fe9c48af9 Mon Sep 17 00:00:00 2001 From: Adam Chlipala Date: Fri, 4 May 2012 10:33:04 -0400 Subject: More diagnostic information about some type class resolution failures --- src/elab_err.sml | 15 ++++----------- 1 file changed, 4 insertions(+), 11 deletions(-) (limited to 'src/elab_err.sml') diff --git a/src/elab_err.sml b/src/elab_err.sml index f21ddce0..0e04cf51 100644 --- a/src/elab_err.sml +++ b/src/elab_err.sml @@ -239,17 +239,10 @@ fun expError env err = ("Type", p_con env c)]) co) | Unresolvable (loc, c) => (ErrorMsg.errorAt loc "Can't resolve type class instance"; - eprefaces' [("Class constraint", p_con env c)(*, - ("Class database", p_list (fn (c, rules) => - box [P.p_con env c, - PD.string ":", - space, - p_list (fn (c, e) => - box [p_exp env e, - PD.string ":", - space, - P.p_con env c]) rules]) - (E.listClasses env))*)]) + eprefaces' ([("Class constraint", p_con env c)] + @ (case E.resolveFailureCause () of + NONE => [] + | SOME c' => [("Reduced to unresolvable", p_con env c')]))) | IllegalRec (x, e) => (ErrorMsg.errorAt (#2 e) "Illegal 'val rec' righthand side (must be a function abstraction)"; eprefaces' [("Variable", PD.string x), -- cgit v1.2.3