🔥 the MonadDead module.

semantic-diff.cabal

@@ -38,7 +38,6 @@ library
                      , Control.Effect
                      -- Effects used for program analysis
                      -- , Control.Monad.Effect.Cache
-                     -- , Control.Monad.Effect.Dead
                      , Control.Monad.Effect.Fresh
                      -- , Control.Monad.Effect.GC
                      -- , Control.Monad.Effect.NonDet

src/Control/Monad/Effect/Dead.hs

@@ -1,23 +0,0 @@
-{-# LANGUAGE GeneralizedNewtypeDeriving, MultiParamTypeClasses, TypeOperators, UndecidableInstances #-}
-module Control.Monad.Effect.Dead where
-
-import Prologue
-import Data.Set (delete)
-import Control.Monad.Effect
-import Control.Monad.Effect.State
-
--- | A set of “dead” (unreachable) terms.
-newtype Dead a = Dead { unDead :: Set a }
-  deriving (Eq, Foldable, Semigroup, Monoid, Ord, Show)
-
--- | 'Monad's offering a readable & writable set of 'Dead' terms.
-class Monad m => MonadDead t m where
-  -- | Update the current 'Dead' set.
-  killAll :: Dead t -> m ()
-
-  -- | Revive a single term, removing it from the current 'Dead' set.
-  revive :: Ord t => t -> m ()
-
-instance (State (Dead t) :< fs) => MonadDead t (Eff fs) where
-  killAll = put
-  revive t = modify (Dead . delete t . unDead)