From 906b063b798e6c0787fd8f514b9d7f1f8eef9cf8 Mon Sep 17 00:00:00 2001
From: letouzey
Date: Mon, 18 Mar 2013 18:55:24 +0000
Subject: Fix for bug #3004 (thanks Hugo!)

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@16317 85f007b7-540e-0410-9357-904b9bb8a0f7
---
 pretyping/evarsolve.ml                      | 5 ++++-
 test-suite/bugs/closed/shouldsucceed/3004.v | 7 +++++++
 2 files changed, 11 insertions(+), 1 deletion(-)
 create mode 100644 test-suite/bugs/closed/shouldsucceed/3004.v

diff --git a/pretyping/evarsolve.ml b/pretyping/evarsolve.ml
index 83462d4c45..a2eebcc242 100644
--- a/pretyping/evarsolve.ml
+++ b/pretyping/evarsolve.ml
@@ -948,7 +948,10 @@ let rec is_constrainable_in k (ev,(fv_rels,fv_ids) as g) t =
   let f,args = decompose_app_vect t in
   match kind_of_term f with
   | Construct (ind,_) ->
-      let params,_ = Array.chop (Inductiveops.inductive_nparams ind) args in
+    let n = Inductiveops.inductive_nparams ind in
+    if n > Array.length args then true (* We don't try to be more clever *)
+    else
+      let params = fst (Array.chop n args) in
       Array.for_all (is_constrainable_in k g) params
   | Ind _ -> Array.for_all (is_constrainable_in k g) args
   | Prod (_,t1,t2) -> is_constrainable_in k g t1 && is_constrainable_in k g t2
diff --git a/test-suite/bugs/closed/shouldsucceed/3004.v b/test-suite/bugs/closed/shouldsucceed/3004.v
new file mode 100644
index 0000000000..896b1958b0
--- /dev/null
+++ b/test-suite/bugs/closed/shouldsucceed/3004.v
@@ -0,0 +1,7 @@
+Set Implicit Arguments.
+Unset Strict Implicit.
+Parameter (M : nat -> Type).
+Parameter (mp : forall (T1 T2 : Type) (f : T1 -> T2), list T1 -> list T2).
+
+Definition foo (s : list {n : nat & M n}) :=
+  let exT := existT in mp (fun x => projT1 x) s.
-- 
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