https://discourse.haskell.org/t/scrap-your-iteration-combinators/12024/34

A.hs

-- src/A.hs
{-# LANGUAGE ScopedTypeVariables, TypeApplications #-}
module A where

import Control.Monad.Trans.State
import Data.Coerce

mapAccumLM :: forall a b c m t.
  (Traversable t, Monad m) => (b -> a -> m (c, a)) -> t b -> a -> m (t c, a)
mapAccumLM f = coerce (traverse @t @(StateT a m) @b @c) f

B.hs

-- src/B.hs
{-# LANGUAGE ScopedTypeVariables #-}
{-# OPTIONS_GHC -ddump-simpl -dsuppress-all -ddump-to-file #-}
module B where

import Control.Monad.Trans.Reader
import A

mapAccumLList :: forall a b c x.
  (b -> a -> ReaderT x Maybe (c, a)) -> [b] -> a -> ReaderT x Maybe ([c], a)
mapAccumLList = mapAccumLM

t.cabal

cabal-version:      3.0
name:               t
version:            0.1.0.0
build-type:         Simple

common warnings
    ghc-options: -Wall

library
    import:           warnings
    exposed-modules:  A, B
    build-depends:    base, transformers
    hs-source-dirs:   src
    default-language: Haskell2010