Also use + for monad.

stdpp/base.v

@@ -1144,27 +1144,27 @@ class with the monad laws). *)
 Class MRet (M : Type → Type) := mret: ∀ {A}, A → M A.
 Global Arguments mret {_ _ _} _ : assert.
 Global Instance: Params (@mret) 3 := {}.
-Global Hint Mode MRet ! : typeclass_instances.
+Global Hint Mode MRet + : typeclass_instances.
 
 Class MBind (M : Type → Type) := mbind : ∀ {A B}, (A → M B) → M A → M B.
 Global Arguments mbind {_ _ _ _} _ !_ / : assert.
 Global Instance: Params (@mbind) 4 := {}.
-Global Hint Mode MBind ! : typeclass_instances.
+Global Hint Mode MBind + : typeclass_instances.
 
 Class MJoin (M : Type → Type) := mjoin: ∀ {A}, M (M A) → M A.
 Global Arguments mjoin {_ _ _} !_ / : assert.
 Global Instance: Params (@mjoin) 3 := {}.
-Global Hint Mode MJoin ! : typeclass_instances.
+Global Hint Mode MJoin + : typeclass_instances.
 
 Class FMap (M : Type → Type) := fmap : ∀ {A B}, (A → B) → M A → M B.
 Global Arguments fmap {_ _ _ _} _ !_ / : assert.
 Global Instance: Params (@fmap) 4 := {}.
-Global Hint Mode FMap ! : typeclass_instances.
+Global Hint Mode FMap + : typeclass_instances.
 
 Class OMap (M : Type → Type) := omap: ∀ {A B}, (A → option B) → M A → M B.
 Global Arguments omap {_ _ _ _} _ !_ / : assert.
 Global Instance: Params (@omap) 4 := {}.
-Global Hint Mode OMap ! : typeclass_instances.
+Global Hint Mode OMap + : typeclass_instances.
 
 Notation "m ≫= f" := (mbind f m) (at level 60, right associativity) : stdpp_scope.
 Notation "( m ≫=.)" := (λ f, mbind f m) (only parsing) : stdpp_scope.