Various fixes on typeclasses:

- Better interface in constrintern w.r.t. evars used during typechecking
- Add "unsatisfiable_constraints" exception which gives back the raw
evar_map that was not satisfied during typeclass search (presentation
could be improved).
- Correctly infer the minimal sort for typeclasses declared as
definitions (everything was in type before).
- Really handle priorities in typeclass eauto: goals produced with higher
priority (lowest number) instances are tried before other of lower
priority goals, regardless of the number of subgoals.
- Change inverse to a notation for flip, now that universe polymorphic
definitions are handled correctly. 
- Add EquivalenceDec class similar to SetoidDec, declaring decision
procedures for equivalences.


git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@10724 85f007b7-540e-0410-9357-904b9bb8a0f7

1 files changed, 3 insertions, 0 deletions

diff --git a/pretyping/typeclasses_errors.ml b/pretyping/typeclasses_errors.ml
index 1648f667a..4db826108 100644
--- a/pretyping/typeclasses_errors.ml
+++ b/pretyping/typeclasses_errors.ml
@@ -28,6 +28,7 @@ type typeclass_error =
     | NotAClass of constr
     | UnboundMethod of global_reference * identifier located (* Class name, method *)
     | NoInstance of identifier located * constr list
+    | UnsatisfiableConstraints of evar_map
     | MismatchedContextInstance of contexts * constr_expr list * named_context (* found, expected *)
 
 exception TypeClassError of env * typeclass_error
@@ -40,4 +41,6 @@ let unbound_method env cid id = typeclass_error env (UnboundMethod (cid, id))
 
 let no_instance env id args = typeclass_error env (NoInstance (id, args))
 
+let unsatisfiable_constraints env evm = typeclass_error env (UnsatisfiableConstraints evm)
+
 let mismatched_ctx_inst env c n m = typeclass_error env (MismatchedContextInstance (c, n, m))