Log Message:
Update transformers-compat to 0.6.5

0.6.5 [2019.05.11]
* Ensure that the backported MonadFail instance for ExceptT is
  available when built against transformers-0.4.*.

0.6.4 [2019.04.01]
* Use more conservative CPP to guard the backported MonadFix instance
  for ListT.

0.6.3 [2019.04.01]
* Backport changes from transformers-0.5.6.*:
  * Backport the MonadFix instance for ListT in
    Control.Monad.Trans.Instances.
  * Generalize the type of except in Control.Monad.Trans.Except.
* Backport MonadFail instances for AccumT, Reverse, and SelectT on
  pre-8.0 versions of GHC by depending on the fail package if
  necessary.
* Backport MonadFail instances for monad transformer types in
  Control.Monad.Trans.Instances.

0.6.2
* transformers-compat now uses automatic flags instead of manual
  ones. This has a number of benefits:
  * There is no need for making several simultaneous releases to
    support each flag combination.
  * As a result, the cabal-install constraint solver should have a
    much easier time figuring out install-plans involving
    transformers-compat.
* Due to old cabal-install bugs, cabal-install-1.16 and older may have
  a harder time installing this package, so it is recommended that you
  use cabal-install-1.18 or later. (Or, if you must use
  cabal-install-1.16 or older, installing transformers-compat with the
  appropriate flags should help.)

0.6.1.6
0.6.1.5
0.6.1.4
0.6.1.3
0.6.1.2
* Each of versions 0.6.1.2–0.6.1.6 is a 0.6.1 build with a different
  set of flags configured. Building this way allows us to work around
  bugs in cabal's backtracker. The 0.6.1 release notes describe the
  changes in this version. This release is configured with -ftwo
  (which works with the transformers-0.2 series).

0.6.1
* Fix an oversight in which the Control.Monad.Trans.Accum and
  Control.Monad.Trans.Select modules were not backported when built
  with the -ffour flag.

0.6.0.6
0.6.0.5
0.6.0.4
0.6.0.3
0.6.0.2
* Each of versions 0.6.0.2–0.6.0.6 is a 0.6 build with a different set
  of flags configured. Building this way allows us to work around bugs
  in cabal's backtracker. The 0.6 release notes describe the changes
  in this version. This release is configured with -ftwo (which works
  with the transformers-0.2 series).

0.6
* Introduce the Data.Functor.Classes.Generic module, which provides
  functions that can generically implement methods in the Eq1, Ord1,
  Read1, and Show1 classes (without the usual boilerplate involved).
* Introduce the generic-deriving flag. When enabled,
  transformers-compat will depend on the generic-deriving library on
  older versions of GHC to backport GHC.Generics support for Generic
  instances and the machinery in Data.Functor.Classes.Generic.
* Some instances were present in Data.Functor.Sum but not in
  Control.Monad.Trans.Instances (e.g., the Generic, Typeable, and Data
  instances for Sum). This has been fixed.
* Backport changes from transformers-0.5.5:
  * Backport the Semigroup instance for Constant
  * Add mapSelect and mapSelectT
  * Define selectToContT (and deprecate selectToCont in favor of that)
  * Define some explicit (*>) definitions to avoid space leaks
* Backport changes from transformers-0.5.4 (i.e., add Bifoldable and
  Bitraversable instances for Data.Functor.Constant)
* Backport changes from transformers-0.5.3:
  * Backport the Control.Monad.Trans.Accum and
    Control.Monad.Trans.Select modules
  * Backport the eitherToErrors and elimLift functions to
    Control.Applicative.Lift
  * Backport Bits, FiniteBits, IsString, Num, Real, Integral,
    Fractional, Floating, RealFrac, and RealFloat instances for
    Data.Functor.Identity
  * Backport Monad, MonadFail, and MonadPlus instances for
    Data.Functor.Reverse
  * Backport Eq1, Ord1, Read1, and Show1 instances for Data.Proxy
* Backport changes from transformers-0.5.2 (i.e., add more INLINE
  annotations)
* Backport changes from transformers-0.5.1 (i.e., add Bounded, Enum,
  Ix, and Storable instances for Identity)

0.5.1.4
0.5.1.3
0.5.1.2
* Each of versions 0.5.1.2–0.5.1.4 is a 0.5.1 build with a different
  set of flags configured. Building this way allows us to work around
  bugs in cabal's backtracker. The 0.5.1 release notes describe the
  changes in this version. This release is configured with -ftwo
  (which works with the transformers-0.2 series).

0.5.1
* Fix a bug in which PolyKinds was enabled on GHC 7.4, resulting in
  interface file bugs on that version of GHC.

0.5.0.4
0.5.0.3
0.5.0.2
* Each of versions 0.5.0.2–0.5.0.4 is a 0.5 build with a different set
  of flags configured. Building this way allows us to work around bugs
  in cabal's backtracker. The 0.5 release notes describe the changes
  in this version. This release is configured with -ftwo (which works
  with the transformers-0.2 series).

0.5
* Update transformers-compat to incorporate changes from the
  transformers-0.5 series. These changes include:
  * The Data.Functor.Classes module was completely redesigned.
  * Modules now have Safe or Trustworthy annotations.
  * Data types and type synonyms are poly-kinded when possible.
* Add Control.Monad.Trans.Instances, a module of orphan instances that
  mimic instances available in later versions of transformers.

0.4.0.4
0.4.0.3
0.4.0.2
* Each of versions 0.4.0.2–0.4.0.4 is a 0.4 build with a different set
  of flags configured. Building this way allows us to work around bugs
  in cabal's backtracker. The 0.4 release notes describe the changes
  in this version. This release is configured with -ftwo (which works
  with the transformers-0.2 series).

0.4
Added support for the missing ExceptT instances from mtl.

This was not done lightly. While this means that by default incurring
a dependency on transformers-compat drags in mtl when you are using an
old transformers, it means that users do not have to orphan these
instances and permits wider adoption of ExceptT.

If you absolutely can't stand mtl and really want this package to
build as valid Haskell98, then you can use cabal install
transformers-compat -f-mtl to avoid incurring the dependency to get
these instances. However, that is effectively an unsupported
configuration.

0.3.3.4
0.3.3.3
0.3.3.2
* Versions 0.3.3.2–0.3.3.4 were a successful attempt to fix build
  problems caused by the cabal backtracker. Each of these is a build
  with a different set of flags configured. This release is configured
  with -ftwo (which works with the transformers-0.2 series).