From cf21be5bfd42720bd1cc8756cfcdb388cdaebd80 Mon Sep 17 00:00:00 2001
From: letouzey
Date: Wed, 26 Oct 2011 13:33:49 +0000
Subject: When checking for emptiness, use Foo.is_empty instead of (=)
 Foo.empty

 Here Foo is Univ.constraints, Univ.universes, Evd.evar_map, Evd.Metamap

 Ok, all these structures are currently ocaml's maps or similar,
 with a unique empty value, and (=) can be used on them in this
 particular case. But using Foo.is_empty is safer : it will work
 even if the underlying representation changes. Example : for
 spotting non-legitimate use of (=) we might embed a type into
 a record with a functional field.

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@14614 85f007b7-540e-0410-9357-904b9bb8a0f7
---
 kernel/environ.ml | 2 +-
 kernel/univ.ml    | 3 +++
 kernel/univ.mli   | 3 +++
 3 files changed, 7 insertions(+), 1 deletion(-)

(limited to 'kernel')

diff --git a/kernel/environ.ml b/kernel/environ.ml
index 7759efb671..7a41e62c47 100644
--- a/kernel/environ.ml
+++ b/kernel/environ.ml
@@ -197,7 +197,7 @@ let add_mind kn mib env =
 (* Universe constraints *)
 
 let add_constraints c env =
-  if c == empty_constraint then
+  if is_empty_constraint c then
     env
   else
     let s = env.env_stratification in
diff --git a/kernel/univ.ml b/kernel/univ.ml
index 7f458f64c1..a89345440a 100644
--- a/kernel/univ.ml
+++ b/kernel/univ.ml
@@ -171,6 +171,7 @@ let is_univ_variable = function
 let type1_univ = Max ([], [UniverseLevel.Set])
 
 let initial_universes = UniverseLMap.empty
+let is_initial_universes = UniverseLMap.is_empty
 
 (* Every UniverseLevel.t has a unique canonical arc representative *)
 
@@ -485,6 +486,8 @@ module Constraint = Set.Make(
 type constraints = Constraint.t
 
 let empty_constraint = Constraint.empty
+let is_empty_constraint = Constraint.is_empty
+
 let union_constraints = Constraint.union
 
 type constraint_function =
diff --git a/kernel/univ.mli b/kernel/univ.mli
index a55775372b..8b3f62910a 100644
--- a/kernel/univ.mli
+++ b/kernel/univ.mli
@@ -47,6 +47,7 @@ val check_eq : check_function
 
 (** The empty graph of universes *)
 val initial_universes : universes
+val is_initial_universes : universes -> bool
 
 (** {6 Constraints. } *)
 
@@ -55,6 +56,8 @@ type constraints
 val empty_constraint : constraints
 val union_constraints : constraints -> constraints -> constraints
 
+val is_empty_constraint : constraints -> bool
+
 type constraint_function = universe -> universe -> constraints -> constraints
 
 val enforce_geq : constraint_function
-- 
cgit v1.2.3