From 300293c119981054c95182a90c829058530a6b6f Mon Sep 17 00:00:00 2001
From: Stephane Glondu <steph@glondu.net>
Date: Sun, 25 Dec 2011 13:19:42 +0100
Subject: Imported Upstream version 8.3.pl3

---
 kernel/inductive.ml | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

(limited to 'kernel/inductive.ml')

diff --git a/kernel/inductive.ml b/kernel/inductive.ml
index ba5e5252..62a48f07 100644
--- a/kernel/inductive.ml
+++ b/kernel/inductive.ml
@@ -1,12 +1,12 @@
 (************************************************************************)
 (*  v      *   The Coq Proof Assistant  /  The Coq Development Team     *)
-(* <O___,, *   INRIA - CNRS - LIX - LRI - PPS - Copyright 1999-2010     *)
+(* <O___,, *   INRIA - CNRS - LIX - LRI - PPS - Copyright 1999-2011     *)
 (*   \VV/  **************************************************************)
 (*    //   *      This file is distributed under the terms of the       *)
 (*         *       GNU Lesser General Public License Version 2.1        *)
 (************************************************************************)
 
-(* $Id: inductive.ml 13368 2010-08-03 13:22:49Z barras $ *)
+(* $Id: inductive.ml 14641 2011-11-06 11:59:10Z herbelin $ *)
 
 open Util
 open Names
@@ -186,13 +186,20 @@ let instantiate_universes env ctx ar argsorts =
   (* This is a Type with constraints *)
  else Type level
 
-let type_of_inductive_knowing_parameters env mip paramtyps =
+exception SingletonInductiveBecomesProp of identifier
+
+let type_of_inductive_knowing_parameters ?(polyprop=true) env mip paramtyps =
   match mip.mind_arity with
   | Monomorphic s ->
       s.mind_user_arity
   | Polymorphic ar ->
       let ctx = List.rev mip.mind_arity_ctxt in
       let ctx,s = instantiate_universes env ctx ar paramtyps in
+      (* The Ocaml extraction cannot handle (yet?) "Prop-polymorphism", i.e.
+         the situation where a non-Prop singleton inductive becomes Prop
+         when applied to Prop params *)
+      if not polyprop && not (is_type0m_univ ar.poly_level) && s = prop_sort
+      then raise (SingletonInductiveBecomesProp mip.mind_typename);
       mkArity (List.rev ctx,s)
 
 (* Type of a (non applied) inductive type *)
-- 
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