fix bts 13854

CHANGES

 * marks an incompatible change
 
+  o fix BTS 13854
+  o fix BTS 13849
   o [syntax] new syntax "constant x:ty" and "constant x:ty = e" to
     introduce constants, as an alternative to "function"
 

examples/bts/13854.why

+theory T
+ type t 'a = A 'a | B
+
+ function f () : () 
+
+  goal g : () = f ()
+
+  goal x : A () <> B
+(*Theorem x : ((A ) = (B :(t unit))). *)
+
+end

examples/bts/13854/13854_T_g_1.v

+(* This file is generated by Why3's Coq driver *)
+(* Beware! Only edit allowed sections below    *)
+Require Import ZArith.
+Require Import Rbase.
+Inductive t (a:Type) :=
+  | A : a -> t a
+  | B : t a.
+Implicit Arguments A.
+Set Contextual Implicit.
+Implicit Arguments B.
+Unset Contextual Implicit.
+
+Parameter f: unit -> unit.
+
+
+(* YOU MAY EDIT THE CONTEXT BELOW *)
+
+(* DO NOT EDIT BELOW *)
+
+Theorem g : (tt = (f tt)).
+(* YOU MAY EDIT THE PROOF BELOW *)
+destruct (f tt); auto.
+Qed.
+(* DO NOT EDIT BELOW *)
+
+

examples/bts/13854/13854_T_x_1.v

+(* This file is generated by Why3's Coq driver *)
+(* Beware! Only edit allowed sections below    *)
+Require Import ZArith.
+Require Import Rbase.
+Inductive t (a:Type) :=
+  | A : a -> t a
+  | B : t a.
+Implicit Arguments A.
+Set Contextual Implicit.
+Implicit Arguments B.
+Unset Contextual Implicit.
+
+Parameter f: unit -> unit.
+
+
+(* YOU MAY EDIT THE CONTEXT BELOW *)
+
+(* DO NOT EDIT BELOW *)
+
+Theorem x : ~ ((A tt) = (B :(t unit))).
+(* YOU MAY EDIT THE PROOF BELOW *)
+discriminate.
+Qed.
+(* DO NOT EDIT BELOW *)
+
+

examples/bts/13854/why3session.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE why3session SYSTEM "why3session.dtd">
+<why3session
+ name="13854/why3session.xml">
+ <prover
+  id="0"
+  name="Coq"
+  version="8.3pl3"/>
+ <file
+  name="../13854.why"
+  verified="true"
+  expanded="true">
+  <theory
+   name="T"
+   locfile="13854/../13854.why"
+   loclnum="1" loccnumb="7" loccnume="8"
+   verified="true"
+   expanded="true">
+   <goal
+    name="g"
+    locfile="13854/../13854.why"
+    loclnum="6" loccnumb="7" loccnume="8"
+    sum="54a27536c38d94e56a04e1a84c5f21e6"
+    proved="true"
+    expanded="true"
+    shape="ainfix =aTuple0afaTuple0">
+    <proof
+     prover="0"
+     timelimit="5"
+     edited="13854_T_g_1.v"
+     obsolete="false"
+     archived="false">
+     <result status="valid" time="0.45"/>
+    </proof>
+   </goal>
+   <goal
+    name="x"
+    locfile="13854/../13854.why"
+    loclnum="8" loccnumb="7" loccnume="8"
+    sum="0c0178555cd601b6589cfe58c26d04bb"
+    proved="true"
+    expanded="true"
+    shape="ainfix =aAaTuple0aBN">
+    <proof
+     prover="0"
+     timelimit="5"
+     edited="13854_T_x_1.v"
+     obsolete="false"
+     archived="false">
+     <result status="valid" time="0.45"/>
+    </proof>
+   </goal>
+  </theory>
+ </file>
+</why3session>

src/printer/coq.ml

@@ -260,6 +260,8 @@ and print_tnode opl opr info fmt t = match t.t_node with
       fprintf fmt (protect_on opr "epsilon %a.@ %a")
         (print_vsty info) v (print_opl_fmla info) f;
       forget_var v
+  | Tapp (fs,[]) when is_fs_tuple fs ->
+      fprintf fmt "tt" 
   | Tapp (fs,pl) when is_fs_tuple fs ->
       fprintf fmt "%a" (print_paren_r (print_term info)) pl
   | Tapp (fs, tl) ->