Replace unused pattern variables with underscore

Addresses new unused-pattern-matching-variable warning on Coq master.

theories/coPset.v

@@ -26,7 +26,7 @@ Fixpoint coPset_wf (t : coPset_raw) : bool :=
   | coPLeaf _ => true
   | coPNode true (coPLeaf true) (coPLeaf true) => false
   | coPNode false (coPLeaf false) (coPLeaf false) => false
-  | coPNode b l r => coPset_wf l && coPset_wf r
+  | coPNode _ l r => coPset_wf l && coPset_wf r
   end.
 Arguments coPset_wf !_ / : simpl nomatch, assert.
 

theories/hlist.v

@@ -22,12 +22,12 @@ Definition htail {A As} (xs : hlist (tcons A As)) : hlist As :=
 Fixpoint hheads {As Bs} : hlist (tapp As Bs) → hlist As :=
   match As with
   | tnil => λ _, hnil
-  | tcons A As => λ xs, hcons (hhead xs) (hheads (htail xs))
+  | tcons _ _ => λ xs, hcons (hhead xs) (hheads (htail xs))
   end.
 Fixpoint htails {As Bs} : hlist (tapp As Bs) → hlist Bs :=
   match As with
   | tnil => id
-  | tcons A As => λ xs, htails (htail xs)
+  | tcons _ _ => λ xs, htails (htail xs)
   end.
 
 Fixpoint himpl (As : tlist) (B : Type) : Type :=