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comparison src/elab_err.sml @ 1742:fca4a6d05ac1

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More diagnostic information about some type class resolution failures
author Adam Chlipala <adam@chlipala.net>
date Fri, 04 May 2012 10:33:04 -0400
parents 0bafdfae2ac7
children 818d4097e2ed
comparison
equal deleted inserted replaced
1741:d6e233db97c8 1742:fca4a6d05ac1
237 (ErrorMsg.errorAt loc "Type class wildcard occurs out of context"; 237 (ErrorMsg.errorAt loc "Type class wildcard occurs out of context";
238 Option.app (fn (e, c) => eprefaces' [("Function", p_exp env e), 238 Option.app (fn (e, c) => eprefaces' [("Function", p_exp env e),
239 ("Type", p_con env c)]) co) 239 ("Type", p_con env c)]) co)
240 | Unresolvable (loc, c) => 240 | Unresolvable (loc, c) =>
241 (ErrorMsg.errorAt loc "Can't resolve type class instance"; 241 (ErrorMsg.errorAt loc "Can't resolve type class instance";
242 eprefaces' [("Class constraint", p_con env c)(*, 242 eprefaces' ([("Class constraint", p_con env c)]
243 ("Class database", p_list (fn (c, rules) => 243 @ (case E.resolveFailureCause () of
244 box [P.p_con env c, 244 NONE => []
245 PD.string ":", 245 | SOME c' => [("Reduced to unresolvable", p_con env c')])))
246 space,
247 p_list (fn (c, e) =>
248 box [p_exp env e,
249 PD.string ":",
250 space,
251 P.p_con env c]) rules])
252 (E.listClasses env))*)])
253 | IllegalRec (x, e) => 246 | IllegalRec (x, e) =>
254 (ErrorMsg.errorAt (#2 e) "Illegal 'val rec' righthand side (must be a function abstraction)"; 247 (ErrorMsg.errorAt (#2 e) "Illegal 'val rec' righthand side (must be a function abstraction)";
255 eprefaces' [("Variable", PD.string x), 248 eprefaces' [("Variable", PD.string x),
256 ("Expression", p_exp env e)]) 249 ("Expression", p_exp env e)])
257 250