Typeclasses: stdlib fixes for new search algorithm

4 files changed, 19 insertions, 3 deletions

diff --git a/theories/Classes/RelationPairs.v b/theories/Classes/RelationPairs.v
index cbde5f9ab..8d1c49822 100644
--- a/theories/Classes/RelationPairs.v
+++ b/theories/Classes/RelationPairs.v
@@ -43,6 +43,9 @@ Generalizable Variables A B RA RB Ri Ro f.
 Definition RelCompFun {A} {B : Type}(R:relation B)(f:A->B) : relation A :=
  fun a a' => R (f a) (f a').
 
+(** Instances on RelCompFun must match syntactically *)
+Typeclasses Opaque RelCompFun. 
+
 Infix "@@" := RelCompFun (at level 30, right associativity) : signature_scope.
 
 Notation "R @@1" := (R @@ Fst)%signature (at level 30) : signature_scope.
@@ -65,6 +68,8 @@ Instance snd_measure : @Measure (A * B) B Snd.
 Definition RelProd {A : Type} {B : Type} (RA:relation A)(RB:relation B) : relation (A*B) :=
  relation_conjunction (@RelCompFun (A * B) A RA fst) (RB @@2).
 
+Typeclasses Opaque RelProd.
+
 Infix "*" := RelProd : signature_scope.
 
 Section RelCompFun_Instances.
diff --git a/theories/MSets/MSetInterface.v b/theories/MSets/MSetInterface.v
index bd8811689..74a7f6df8 100644
--- a/theories/MSets/MSetInterface.v
+++ b/theories/MSets/MSetInterface.v
@@ -345,6 +345,9 @@ Module Type WRawSets (E : DecidableType).
       predicate [Ok]. If [Ok] isn't decidable, [isok] may be the
       always-false function. *)
   Parameter isok : t -> bool.
+  (** MS: 
+    Dangerous instance, the [isok s = true] hypothesis cannot be discharged
+   with typeclass resolution. Is it really an instance? *)
   Declare Instance isok_Ok s `(isok s = true) : Ok s | 10.
 
   (** Logical predicates *)
diff --git a/theories/Numbers/NatInt/NZGcd.v b/theories/Numbers/NatInt/NZGcd.v
index 1d3672943..7564c2061 100644
--- a/theories/Numbers/NatInt/NZGcd.v
+++ b/theories/Numbers/NatInt/NZGcd.v
@@ -60,7 +60,9 @@ Proof.
  intros n. exists 0. now nzsimpl.
 Qed.
 
-Hint Rewrite divide_1_l divide_0_r : nz.
+(* MS: These rewrites apply to any subterm of type Z, do not try
+  them automatically *)
+(* Hint Rewrite divide_1_l divide_0_r : nz. *)
 
 Lemma divide_0_l : forall n, (0 | n) -> n==0.
 Proof.
diff --git a/theories/Numbers/Rational/SpecViaQ/QSig.v b/theories/Numbers/Rational/SpecViaQ/QSig.v
index a40d94059..8e20fd060 100644
--- a/theories/Numbers/Rational/SpecViaQ/QSig.v
+++ b/theories/Numbers/Rational/SpecViaQ/QSig.v
@@ -115,7 +115,10 @@ Ltac solve_wd2 := intros x x' Hx y y' Hy; qify; now rewrite Hx, Hy.
 Local Obligation Tactic := solve_wd2 || solve_wd1.
 
 Instance : Measure to_Q.
-Instance eq_equiv : Equivalence eq := {}.
+Instance eq_equiv : Equivalence eq.
+Proof.
+  change eq with (RelCompFun Qeq to_Q); apply _.
+Defined.
 
 Program Instance lt_wd : Proper (eq==>eq==>iff) lt.
 Program Instance le_wd : Proper (eq==>eq==>iff) le.
@@ -141,7 +144,10 @@ Proof. intros. qify. destruct (Qcompare_spec [x] [y]); auto. Qed.
 (** Let's implement [TotalOrder] *)
 
 Definition lt_compat := lt_wd.
-Instance lt_strorder : StrictOrder lt := {}.
+Instance lt_strorder : StrictOrder lt.
+Proof.
+  change lt with (RelCompFun Qlt to_Q); apply _.
+Qed.
 
 Lemma le_lteq : forall x y, x<=y <-> x<y \/ x==y.
 Proof. intros. qify. apply Qle_lteq. Qed.