perf: missing annotations and helper instances

src/Lean/Compiler/LCNF/CompilerM.lean

@@ -42,6 +42,9 @@ structure CompilerM.Context where
 
 abbrev CompilerM := ReaderT CompilerM.Context $ StateRefT CompilerM.State CoreM
 
+@[alwaysInline]
+instance : Monad CompilerM := let i := inferInstanceAs (Monad CompilerM); { pure := i.pure, bind := i.bind }
+
 @[inline] def withPhase (phase : Phase) (x : CompilerM α) : CompilerM α :=
   withReader (fun ctx => { ctx with phase }) x
 

src/Lean/Compiler/LCNF/Simp/SimpM.lean

@@ -75,6 +75,9 @@ structure State where
 
 abbrev SimpM := ReaderT Context $ StateRefT State DiscrM
 
+@[alwaysInline]
+instance : Monad SimpM := let i := inferInstanceAs (Monad SimpM); { pure := i.pure, bind := i.bind }
+
 instance : MonadFVarSubst SimpM false where
   getSubst := return (← get).subst
 

src/Lean/CoreM.lean

@@ -76,6 +76,7 @@ abbrev CoreM := ReaderT Context <| StateRefT State (EIO Exception)
 
 -- Make the compiler generate specialized `pure`/`bind` so we do not have to optimize through the
 -- whole monad stack at every use site. May eventually be covered by `deriving`.
+@[alwaysInline]
 instance : Monad CoreM := let i := inferInstanceAs (Monad CoreM); { pure := i.pure, bind := i.bind }
 
 instance : Inhabited (CoreM α) where

src/Lean/Meta/Basic.lean

@@ -300,6 +300,7 @@ abbrev MetaM  := ReaderT Context $ StateRefT State CoreM
 
 -- Make the compiler generate specialized `pure`/`bind` so we do not have to optimize through the
 -- whole monad stack at every use site. May eventually be covered by `deriving`.
+@[alwaysInline]
 instance : Monad MetaM := let i := inferInstanceAs (Monad MetaM); { pure := i.pure, bind := i.bind }
 
 instance : Inhabited (MetaM α) where