Backtrack sur suppression des vars anonymes des contextes d'evars (echec Case15.v et CasesDep.v pas anormal)

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@9437 85f007b7-540e-0410-9357-904b9bb8a0f7

2 files changed, 21 insertions, 40 deletions

diff --git a/pretyping/evarutil.ml b/pretyping/evarutil.ml
index 53c619912..207ad88b3 100644
--- a/pretyping/evarutil.ml
+++ b/pretyping/evarutil.ml
@@ -168,15 +168,20 @@ let push_rel_context_to_named_context env typ =
     fold_named_context (fun env (id,b,_) l -> mkVar id :: l) env ~init:[] in
   (* move the rel context to a named context and extend the instance 
      with vars of the rel context *)
+(*
   let fv = free_rels typ in
+*)
   let avoid = ids_of_named_context (named_context env) in
   let n = rel_context_length (rel_context env) in
   let (subst, _, _, inst, env) =
     Sign.fold_rel_context
-      (fun (na,c,t) (subst, n, avoid, inst, env) -> match na with
+      (fun (na,c,t) (subst, n, avoid, inst, env) ->
+(*
+	match na with
 	| Anonymous when not (Intset.mem n fv) -> 
 	    (dummy_var::subst, n-1, avoid, inst, env)
 	| _ ->
+*)
 	    let id = next_name_away na avoid in
 	    ((mkVar id)::subst, n-1, id::avoid, mkRel n::inst,
 	    push_named (id,option_map (substl subst) c,substl subst t) env))
diff --git a/test-suite/complexity/evars_subst.v b/test-suite/complexity/evars_subst.v
index 58a09dd3f..d79d9f0e0 100644
--- a/test-suite/complexity/evars_subst.v
+++ b/test-suite/complexity/evars_subst.v
@@ -2,20 +2,20 @@
 (* Expected time < 1.00s *)
 
 (* Let n be the number of let-in. The complexity comes from the fact
-that each implicit arguments of f was in a larger and larger
-context. To compute the type of "let _ := f ?Tn 0 in f ?T 0", "f ?Tn
-0" is substituted in the type of "f ?T 0" which is ?T. This type is an
-evar instantiated on the n variables denoting the "f ?Ti 0".  One
-obtain "?T[1;...;n-1;f ?Tn[1;...;n-1] 0]". To compute the type of "let
-_ := f ?Tn-1 0 in let _ := f ?Tn 0 in f ?T 0", another substitution is
-done leading to ?T[1;...;n-2;f ?Tn[1;...;n-2] 0;f ?Tn[1;...;n-2;f
-?Tn[1;...;n-2] 0] 0]" and so on. At the end, we get a term of
-exponential size *)
-
-(* A way to cut the complexity is to remove the dependency in
-   anonymous variables in evars; another approach would be to
-   substitute lazily and/or to simultaneously substitute let binders
-   and evars *)
+   that each implicit arguments of f was in a larger and larger
+   context. To compute the type of "let _ := f ?Tn 0 in f ?T 0", 
+   "f ?Tn 0" is substituted in the type of "f ?T 0" which is ?T. This
+   type is an evar instantiated on the n variables denoting the "f ?Ti 0".
+   One obtain "?T[1;...;n-1;f ?Tn[1;...;n-1] 0]". To compute the
+   type of "let _ := f ?Tn-1 0 in let _ := f ?Tn 0 in f ?T 0", another
+   substitution is done leading to 
+   "?T[1;...;n-2;f ?Tn[1;...;n-2] 0;f ?Tn[1;...;n-2;f ?Tn[1;...;n-2] 0] 0]"
+   and so on. At the end, we get a term of exponential size *)
+
+(* A way to cut the complexity could have been to remove the dependency in
+   anonymous variables in evars but this breaks intuitive behaviour
+   (see Case15.v); another approach could be to substitute lazily
+   and/or to simultaneously substitute let binders and evars *)
 
 Variable P : Set -> Set.
 Variable f : forall A : Set, A -> P A.
@@ -24,36 +24,12 @@ Check
   let _ := f _ 0 in
   let _ := f _ 0 in
   let _ := f _ 0 in
- 
-  let _ := f _ 0 in
-  let _ := f _ 0 in
-  let _ := f _ 0 in
-
-  let _ := f _ 0 in
-  let _ := f _ 0 in
-  let _ := f _ 0 in
-  let _ := f _ 0 in
-  let _ := f _ 0 in
-
-  let _ := f _ 0 in
-  let _ := f _ 0 in
-  let _ := f _ 0 in
-  let _ := f _ 0 in
-  let _ := f _ 0 in
-
-  let _ := f _ 0 in
-  let _ := f _ 0 in
-  let _ := f _ 0 in
-  let _ := f _ 0 in
-  let _ := f _ 0 in
-
-  let _ := f _ 0 in
-  let _ := f _ 0 in
   let _ := f _ 0 in
  
   let _ := f _ 0 in
   let _ := f _ 0 in
   let _ := f _ 0 in
+  let _ := f _ 0 in
 
   let _ := f _ 0 in
   let _ := f _ 0 in