diff --git a/docs/users_guide/8.2.1-notes.rst b/docs/users_guide/8.2.1-notes.rst
deleted file mode 100644
index d46f08dd94656449d0b7caf29839e884ec7f9acd..0000000000000000000000000000000000000000
--- a/docs/users_guide/8.2.1-notes.rst
+++ /dev/null
@@ -1,527 +0,0 @@
-.. _release-8-2-1:
-
-Release notes for version 8.2.1
-===============================
-
-The significant changes to the various parts of the compiler are listed
-in the following sections. There have also been numerous bug fixes and
-performance improvements over the 8.0 branch.
-
-Highlights
-----------
-
-The highlights since the 8.0 release include:
-
-- A new, more expressive ``Typeable`` mechanism, ``Type.Reflection``
-
-- Colorful error messages with caret diagnostics
-
-- SCC annotations can now be used for declarations.
-
-- Heap overflow throws an exception in certain circumstances.
-
-- Improved code generation of join points
-
-- Deriving strategies
-
-- Compact regions support, allowing efficient garbage collection of large heaps
-
-- More reliable DWARF debug information
-
-Full details
-------------
-
-Package system
-~~~~~~~~~~~~~~
-
-- The long awaited Backpack module system is now fully usable. See
- :ghc-wiki:`the GHC Wiki <Backpack>` for details.
-
-Language
-~~~~~~~~
-
-- Pattern synonym signatures can now be applied to multiple patterns, just like
- value-level binding signatures. See :ref:`patsyn-typing` for details.
-
-- It is now possible to explicitly pick a strategy to use when deriving a
- class instance using the :ghc-flag:`-XDerivingStrategies` language extension
- (see :ref:`deriving-strategies`).
-
-- The new :ghc-flag:`-XUnboxedSums` extension allows more efficient representation
- of sum data. Some future GHC release will have support for worker/wrapper
- transformation of sum arguments and constructor unpacking.
-
-- Support for overloaded record fields via a new ``HasField`` class and
- associated compiler logic (see :ref:`record-field-selector-polymorphism`)
-
-- GHC now recognizes the ``COMPLETE`` language pragma, allowing the user to
- specify sets of patterns (including pattern synonyms) which constitute a
- complete pattern match. See :ref:`complete-pragma` for details.
-
-Compiler
-~~~~~~~~
-
-- GHC will now use ``ld.gold`` or ``ld.lld`` instead of the system's default
- ``ld``, if available. Linker availability will be evaluated at ``configure``
- time. The user can manually override which linker to use by passing the ``LD``
- variable to ``configure``. You can revert to the old behavior of using the
- system's default ``ld`` by passing the ``--disable-ld-override`` flag to
- ``configure``.
-
-- GHC now uses section splitting (i.e. :ghc-flag:`-split-sections`) instead of
- object splitting (i.e. :ghc-flag:`-split-objs`) as the default mechanism for
- linker-based dead code removal. While the effect is the same, split sections
- tends to produce significantly smaller objects than split objects and more
- closely mirrors the approach used by other compilers. Split objects will
- be deprecated and eventually removed in a future GHC release.
-
- Note that some versions of the ubiquitous BFD linker exhibit performance
- trouble with large libraries with section splitting enabled (see
- :ghc-ticket:`13739`). It is recommended that you use either the ``gold`` or
- ``lld`` linker if you observe this. This will require that you install one of
- these compilers, rerun ``configure``, and reinstall GHC.
-
- Split sections is enabled by default in the official binary distributions for
- platforms that support it.
-
-- Old profiling flags ``-auto-all``, ``-auto``, and ``-caf-all`` are deprecated
- and their usage provokes a compile-time warning.
-
-- Support for adding cost centres to declarations is added. The same ``SCC``
- syntax can be used, in addition to a new form for specifying the cost centre
- name. See :ref:`scc-pragma` for examples.
-
-- GHC is now much more particular about :ghc-flag:`-XDefaultSignatures`. The
- type signature for a default method of a type class must now be the same as
- the corresponding main method's type signature modulo differences in the
- signatures' contexts. Otherwise, the typechecker will reject that class's
- definition. See :ref:`class-default-signatures` for further details.
-
-- :ghc-flag:`-XDeriveAnyClass` is no longer limited to type classes whose
- argument is of kind ``*`` or ``* -> *``.
-
-- The means by which :ghc-flag:`-XDeriveAnyClass` infers instance contexts has
- been completely overhauled. The instance context is now inferred using the
- type signatures (and default type signatures) of the derived class's methods
- instead of using the datatype's definition, which often led to
- over-constrained instances or instances that didn't typecheck (or worse,
- triggered GHC panics). See the section on
- :ref:`DeriveAnyClass <derive-any-class>` for more details.
-
-- GHC now allows standalone deriving using :ghc-flag:`-XDeriveAnyClass` on
- any data type, even if its data constructors are not in scope. This is
- consistent with the fact that this code (in the presence of
- :ghc-flag:`-XDeriveAnyClass`): ::
-
- deriving instance C T
-
- is exactly equivalent to: ::
-
- instance C T
-
- and the latter code has no restrictions about whether the data constructors
- of ``T`` are in scope.
-
-- :ghc-flag:`-XGeneralizedNewtypeDeriving` now supports deriving type classes
- with associated type families. See the section on
- :ref:`GeneralizedNewtypeDeriving and associated type families
- <gnd-and-associated-types>`.
-
-- :ghc-flag:`-XGeneralizedNewtypeDeriving` will no longer infer constraints
- when deriving a class with no methods. That is, this code: ::
-
- class Throws e
- newtype Id a = MkId a
- deriving Throws
-
- will now generate this instance: ::
-
- instance Throws (Id a)
-
- instead of this instance: ::
-
- instance Throws a => Throws (Id a)
-
- This change was motivated by the fact that the latter code has a strictly
- redundant ``Throws a`` constraint, so it would emit a warning when compiled
- with :ghc-flag:`-Wredundant-constraints`. The latter instance could still
- be derived if so desired using :ghc-flag:`-XStandaloneDeriving`: ::
-
- deriving instance Throws a => Throws (Id a)
-
-- Add warning flag :ghc-flag:`-Wcpp-undef` which passes ``-Wundef`` to the C
- pre-processor causing the pre-processor to warn on uses of the ``#if``
- directive on undefined identifiers.
-
-- GHC will no longer automatically infer the kind of higher-rank type synonyms;
- you must explicitly annotate the synonym with a kind signature.
- For example, given::
-
- data T :: (forall k. k -> Type) -> Type
-
- to define a synonym of ``T``, you must write::
-
- type TSyn = (T :: (forall k. k -> Type) -> Type)
-
-- The Mingw-w64 toolchain for the Windows version of GHC has been updated. GHC now uses
- `GCC 6.2.0` and `binutils 2.27`.
-
-- Previously, :ghc-flag:`-Wmissing-methods` would not warn whenever a type
- class method beginning with an underscore was not implemented in an instance.
- For instance, this code would compile without any warnings: ::
-
- class Foo a where
- _Bar :: a -> Int
-
- instance Foo Int
-
- :ghc-flag:`-Wmissing-methods` will now warn that ``_Bar`` is not implemented
- in the ``Foo Int`` instance.
-
-- A new flag :ghc-flag:`-ddump-json` has been added. This flag dumps compiler
- output as JSON documents. It is experimental and will be refined depending
- on feedback from tooling authors for the next release.
-
-- GHC is now able to better optimize polymorphic expressions by using known
- superclass dictionaries where possible. Some examples: ::
-
- -- uses of `Monad IO` or `Applicative IO` here are improved
- foo :: MonadBaseControl IO m => ...
-
- -- uses of `Monoid MyMonoid` here are improved
- bar :: MonadWriter MyMonoid m => ...
-
-- GHC now derives the definition of ``<$`` when using :ghc-flag:`-XDeriveFunctor`
- rather than using the default definition. This prevents unnecessary
- allocation and a potential space leak when deriving ``Functor`` for
- a recursive type.
-
-- The :ghc-flag:`-XExtendedDefaultRules` extension now defaults multi-parameter
- typeclasses. See :ghc-ticket:`12923`.
-
-- GHC now ignores ``RULES`` for data constructors (:ghc-ticket:`13290`).
- Previously, it accepted::
-
- {-# RULES "NotAllowed" forall x. Just x = e #-}
-
- That rule will no longer take effect, and a warning will be issued. ``RULES``
- may still mention data constructors, but not in the outermost position::
-
- {-# RULES "StillWorks" forall x. f (Just x) = e #-}
-
-- Type synonyms can no longer appear in the class position of an instance.
- This means something like this is no longer allowed: ::
-
- type ReadShow a = (Read a, Show a)
- instance Read Foo
- instance Show Foo
- instance ReadShow Foo -- illegal
-
- See :ghc-ticket:`13267`.
-
-- Validity checking for associated type family instances has tightened
- somewhat. Before, this would be accepted: ::
-
- class Foo a where
- type Bar a
-
- instance Foo (Either a b) where
- type Bar (Either c d) = d -> c
-
- This is now disallowed, as the type variables used in the `Bar` instance do
- not match those in the instance head. This instance can be fixed by changing
- it to: ::
-
- instance Foo (Either a b) where
- type Bar (Either a b) = b -> a
-
- See the section on :ref:`associated type family instances <assoc-data-inst>`
- for more information.
-
-- A bug involving the interaction between :ghc-flag:`-XMonoLocalBinds` and
- :ghc-flag:`-XPolyKinds` has been fixed. This can cause some programs to fail
- to typecheck in case explicit kind signatures are not provided. See
- :ref:`kind-generalisation` for an example.
-
-GHCi
-~~~~
-
-- Added :ghc-flag:`-flocal-ghci-history` which uses current directory for `.ghci-history`.
-
-- Added support for :ghc-flag:`-XStaticPointers` in interpreted modules. Note, however,
- that ``static`` expressions are still not allowed in expressions evaluated in the REPL.
-
-- Added support for :ghci-cmd:`:type +d` and :ghci-cmd:`:type +v`. (:ghc-ticket:`11975`)
-
-Template Haskell
-~~~~~~~~~~~~~~~~
-
-- Reifying types that contain unboxed tuples now works correctly. (Previously,
- Template Haskell reified unboxed tuples as boxed tuples with twice their
- appropriate arity.)
-
-- Splicing singleton unboxed tuple types (e.g., ``(# Int #)``) now works
- correctly. Previously, Template Haskell would implicitly remove the
- parentheses when splicing, which would turn ``(# Int #)`` into ``Int``.
-
-- Add support for type signatures in patterns. (:ghc-ticket:`12164`)
-
-- Make quoting and reification return the same types. (:ghc-ticket:`11629`)
-
-- More kind annotations appear in the left-hand sides of reified closed
- type family equations, in order to disambiguate types that would otherwise
- be ambiguous in the presence of :ghc-flag:`-XPolyKinds`.
- (:ghc-ticket:`12646`)
-
-- Quoted type signatures are more accurate with respect to implicitly
- quantified type variables. Before, if you quoted this: ::
-
- [d| id :: a -> a
- id x = x
- |]
-
- then the code that Template Haskell would give back to you would actually be
- this instead: ::
-
- id :: forall a. a -> a
- id x = x
-
- That is, quoting would explicitly quantify all type variables, even ones
- that were implicitly quantified in the source. This could be especially
- harmful if a kind variable was implicitly quantified. For example, if
- you took this quoted declaration: ::
-
- [d| idProxy :: forall proxy (b :: k). proxy b -> proxy b
- idProxy x = x
- |]
-
- and tried to splice it back in, you'd get this instead: ::
-
- idProxy :: forall k proxy (b :: k). proxy b -> proxy b
- idProxy x = x
-
- Now ``k`` is explicitly quantified, and that requires turning on
- :ghc-flag:`-XTypeInType`, whereas the original declaration did not!
-
- Template Haskell quoting now respects implicit quantification in type
- signatures, so the quoted declarations above now correctly leave the
- type variables ``a`` and ``k`` as implicitly quantified.
- (:ghc-ticket:`13018` and :ghc-ticket:`13123`)
-
-- Looking up type constructors with symbol names (e.g., ``+``) now works
- as expected (:ghc-ticket:`11046`)
-
-
-Runtime system
-~~~~~~~~~~~~~~
-
-- Heap overflow throws a catchable exception, provided that it was detected
- by the RTS during a GC cycle due to the program exceeding a limit set by
- ``+RTS -M`` (see :rts-flag:`-M ⟨size⟩`), and not due to an allocation being refused
- by the operating system. This exception is thrown to the same thread that
- receives ``UserInterrupt`` exceptions, and may be caught by user programs.
-
-- Added support for *Compact Regions*, which offer a way to manually
- move long-lived data outside of the heap so that the garbage
- collector does not have to trace it repeatedly. Compacted data can
- also be serialized, stored, and deserialized again later by the same
- program. For more details see the :ghc-compact-ref:`GHC.Compact.` module.
- Moreover, see the ``compact`` library on `Hackage
- <https://hackage.haskell.org/package/compact>`_ for a high-level interface.
-
-- There is new support for improving performance on machines with a
- Non-Uniform Memory Architecture (NUMA). See :rts-flag:`--numa`.
- This is supported on Linux and Windows systems.
-
-- The garbage collector can be told to use fewer threads than the
- global number of capabilities set by :rts-flag:`-N ⟨x⟩`. By default, the garbage
- collector will use a number of threads equal to the lesser of the global number
- of capabilities or the number of physical cores. See :rts-flag:`-qn ⟨x⟩`, and a
- `blog post <http://simonmar.github.io/posts/2016-12-08-Haskell-in-the-datacentre.html>`_
- that describes this.
-
-- The :ref:`heap profiler <prof-heap>` can now emit heap census data to the GHC
- event log, allowing heap profiles to be correlated with other tracing events
- (see :ghc-ticket:`11094`).
-
-- Some bugs have been fixed in the stack-trace implementation in the
- profiler that sometimes resulted in incorrect stack traces and
- costs attributed to the wrong cost centre stack (see :ghc-ticket:`5654`).
-
-- Added processor group support for Windows. This allows the runtime to allocate
- threads to all cores in systems which have multiple processor groups.
- (e.g. > 64 cores, see :ghc-ticket:`11054`)
-
-- Output of :ref:`Event log <rts-eventlog>` data can now be configured,
- enabling external tools to collect and analyze the event log data while the
- application is still running.
-
-- ``advapi32``, ``shell32`` and ``user32`` are now automatically loaded in GHCi.
- ``libGCC`` is also loaded when a dependency requires it. See
- :ghc-ticket:`13189`.
-
-hsc2hs
-~~~~~~
-
-- Version number 0.68.2
-
-Libraries
----------
-
-array
-~~~~~
-
-- Version number 0.5.2.0 (was 0.5.0.0)
-
-.. _lib-base:
-
-base
-~~~~
-
-See ``changelog.md`` in the ``base`` package for full release notes.
-
-- Version number 4.10.0.0 (was 4.9.0.0)
-
-- ``Data.Either`` now provides ``fromLeft`` and ``fromRight``
-
-- ``Data.Type.Coercion`` now provides ``gcoerceWith``, which is analogous to
- ``gcastWith`` from ``Data.Type.Equality``.
-
-- The ``Read1`` and ``Read2`` classes in ``Data.Functor.Classes`` have new
- methods, ``liftReadList(2)`` and ``liftReadListPrec(2)``, that are defined in
- terms of ``ReadPrec`` instead of ``ReadS``. This matches the interface
- provided in GHC's version of the ``Read`` class, and allows users to write
- more efficient ``Read1`` and ``Read2`` instances.
-
-- Add ``type family AppendSymbol (m :: Symbol) (n :: Symbol) :: Symbol`` to
- ``GHC.TypeLits``
-
-- Add ``GHC.TypeNats`` module with ``Natural``-based ``KnownNat``. The ``Nat``
- operations in ``GHC.TypeLits`` are a thin compatibility layer on top.
- Note: the ``KnownNat`` evidence is changed from an ``Integer`` to a ``Natural``.
-
-- ``liftA2`` is now a method of the ``Applicative`` class. ``Traversable``
- deriving has been modified to use ``liftA2`` for the first two elements
- traversed in each constructor. ``liftA2`` is not yet in the ``Prelude``,
- and must currently be imported from ``Control.Applicative``. It is likely
- to be added to the ``Prelude`` in the future.
-
-binary
-~~~~~~
-
-- Version number 0.8.5.1 (was 0.7.1.0)
-
-bytestring
-~~~~~~~~~~
-
-- Version number 0.10.8.2 (was 0.10.4.0)
-
-Cabal
-~~~~~
-
-- Version number 2.0.0.0 (was 1.24.2.0)
-
-containers
-~~~~~~~~~~
-
-- Version number 0.5.10.2 (was 0.5.4.0)
-
-deepseq
-~~~~~~~
-
-- Version number 1.4.3.0 (was 1.3.0.2)
-
-directory
-~~~~~~~~~
-
-- Version number 1.3.0.2 (was 1.2.0.2)
-
-filepath
-~~~~~~~~
-
-- Version number 1.4.1.2 (was 1.3.0.2)
-
-ghc
-~~~
-
-- Version number 8.2.1
-
-ghc-boot
-~~~~~~~~
-
-- This is an internal package. Use with caution.
-
-ghc-compact
-~~~~~~~~~~~
-
-The ``ghc-compact`` library provides an experimental API for placing immutable
-data structures into a contiguous memory region. Data in these regions is not
-traced during garbage collection and can be serialized to disk or over the
-network.
-
-- Version number 0.1.0.0 (newly added)
-
-ghc-prim
-~~~~~~~~
-
-- Version number 0.5.1.0 (was 0.3.1.0)
-
-- Added new ``isByteArrayPinned#`` and ``isMutableByteArrayPinned#`` operation.
-
-- New function ``noinline`` in ``GHC.Magic`` lets you mark that a function
- should not be inlined. It is optimized away after the simplifier runs.
-
-hoopl
-~~~~~
-
-- Version number 3.10.2.2 (was 3.10.2.1)
-
-hpc
-~~~
-
-- Version number 0.6.0.3 (was 0.6.0.2)
-
-integer-gmp
-~~~~~~~~~~~
-
-- Version number 1.0.0.1 (was 1.0.0.1)
-
-process
-~~~~~~~
-
-- Version number 1.6.1.0 (was 1.4.3.0)
-
-template-haskell
-~~~~~~~~~~~~~~~~
-
-- Version 2.12.0.0 (was 2.11.1.0)
-
-- Added support for unboxed sums :ghc-ticket:`12478`.
-
-- Added support for visible type applications :ghc-ticket:`12530`.
-
-time
-~~~~
-
-- Version number 1.8.0.1 (was 1.6.0.1)
-
-unix
-~~~~
-
-- Version number 2.7.2.2 (was 2.7.2.1)
-
-Win32
-~~~~~
-
-- Version number 2.5.4.1 (was 2.3.1.1)
-
-Known bugs
-----------
-
-- At least one known program regresses in compile time significantly over 8.0.
- See :ghc-ticket:`13535`.
-
-- Some uses of type applications may cause GHC to panic. See :ghc-ticket:`13819`.
-
-- The compiler may loop during typechecking on some modules using
- :ghc-flag:`-XUndecidableInstances`. See :ghc-ticket:`13943`.
diff --git a/docs/users_guide/8.4.1-notes.rst b/docs/users_guide/8.4.1-notes.rst
deleted file mode 100644
index 305f9629c0d5d1970b817bd156b59fa65ca8ef67..0000000000000000000000000000000000000000
--- a/docs/users_guide/8.4.1-notes.rst
+++ /dev/null
@@ -1,441 +0,0 @@
-.. _release-8-4-1:
-
-Release notes for version 8.4.1
-===============================
-
-The significant changes to the various parts of the compiler are listed in the
-following sections. There have also been numerous bug fixes and performance
-improvements over the 8.2.1 release.
-
-
-Highlights
-----------
-
-The highlights, since the 8.2.1 release, are:
-
-- GHC is now capable of deriving more instances
-
-- More refinement of the :ghc-flag:`-XTypeInType` story and improvements in type
- error messages.
-
-- Further improvements in code generation
-
-- Many, many bug fixes.
-
-
-Full details
-------------
-
-Language
-~~~~~~~~
-
-- Data families have been generalised a bit: a data family declaration can now
- end with a kind variable ``k`` instead of ``Type``. Additionally, data/newtype
- instance no longer need to list all the patterns of the family if they don't
- wish to; this is quite like how regular datatypes with a kind signature can omit
- some type variables.
-
-- There are now fewer restrictions regarding whether kind variables can appear
- on the right-hand sides of type and data family instances. Before, there was
- a strict requirements that all kind variables on the RHS had to be explicitly
- bound by type patterns on the LHS. Now, kind variables can be *implicitly*
- bound, which allows constructions like these: ::
-
- data family Nat :: k -> k -> *
- -- k is implicitly bound by an invisible kind pattern
- newtype instance Nat :: (k -> *) -> (k -> *) -> * where
- Nat :: (forall xx. f xx -> g xx) -> Nat f g
-
- class Funct f where
- type Codomain f :: *
- instance Funct ('KProxy :: KProxy o) where
- -- o is implicitly bound by the kind signature
- -- of the LHS type pattern ('KProxy)
- type Codomain 'KProxy = NatTr (Proxy :: o -> *)
-
-- Implicitly bidirectional pattern synonyms no longer allow bang patterns
- (``!``) or irrefutable patterns (``~``) on the right-hand side. Previously,
- this was allowed, although the bang patterns and irrefutable patterns would
- be silently ignored when used in an expression context. This is now a proper
- error, and explicitly bidirectional pattern synonyms should be used in their
- stead. That is, instead of using this (which is an error): ::
-
- pattern StrictJust a = Just !a
-
- Use this: ::
-
- pattern StrictJust a <- Just !a where
- StrictJust !a = Just a
-
-- GADTs with kind-polymorphic type arguments now require :ghc-flag:`-XTypeInType`.
- For instance, consider the following, ::
-
- data G :: k -> * where
- GInt :: G Int
- GMaybe :: G Maybe
-
- In previous releases this would compile with :ghc-flag:`-XPolyKinds` alone due
- to bug :ghc-ticket:`13391`. As of GHC 8.4, however, this requires
- :ghc-flag:`-XTypeInType`. Note that since GADT kind signatures aren't generalized,
- this will also require that you provide a :ref:`CUSK
- <complete-kind-signatures>` by explicitly quantifying over the kind argument,
- ``k``, ::
-
- data G :: forall k. k -> * where
- GInt :: G Int
- GMaybe :: G Maybe
-
-- The order in which type variables are quantified in GADT constructor type
- signatures has changed. Before, if you had ``MkT`` as below: ::
-
- data T a where
- MkT :: forall b a. b -> T a
-
- Then the type of ``MkT`` would (counterintuitively) be
- ``forall a b. b -> T a``! Now, GHC quantifies the type variables in the
- order that the users writes them, so the type of ``MkT`` is now
- ``forall b a. b -> T a`` (this matters for :ghc-flag:`-XTypeApplications`).
-
-- The new :ghc-flag:`-XEmptyDataDeriving` extension allows deriving ``Eq``,
- ``Ord``, ``Read``, and ``Show`` instances directly for empty data types, as
- in ``data Empty deriving Eq``. (Previously, this would require the use of
- :ghc-flag:`-XStandaloneDeriving` to accomplish.)
-
- One can also now derive ``Data`` instances directly for empty data types (as
- in ``data Empty deriving Data``) without needing to use
- :ghc-flag:`-XStandaloneDeriving`. However, since already requires a GHC
- extension (:ghc-flag:`-XDeriveDataTypeable`), one does not need to enable
- :ghc-flag:`-XEmptyDataDeriving` to do so. This also goes for other classes
- which require extensions to derive, such as :ghc-flag:`-XDeriveFunctor`.
-
-- Hexadecimal floating point literals (e.g. ``0x0.1p4``), enabled with
- :ghc-flag:`-XHexFloatLiterals`. See
- :ref:`Hexadecimal floating point literals <hex-float-literals>`
- for the full details.
-
-Compiler
-~~~~~~~~
-
-- LLVM code generator (e.g. :ghc-flag:`-fllvm`) compatible with LLVM releases in
- the |llvm-version| series.
-
-- Add warning flag :ghc-flag:`-Wmissing-export-lists` which causes the type
- checker to warn when a module does not include an explicit export list.
-
-- The ``configure`` script now no longer accepts ``--with-TOOL`` flags (e.g.
- ``--with-nm``, ``--with-ld``, etc.). Instead, these are taken from environment
- variables, as is typical in ``autoconf`` scripts. For instance,
- ``./configure --with-nm=/usr/local/bin/nm`` turns into
- ``./configure NM=/usr/local/bin/nm``.
-
-- Derived ``Functor``, ``Foldable``, and ``Traversable`` instances are now
- optimized when their last type parameters have phantom roles.
- Specifically, ::
-
- fmap _ = coerce
- traverse _ x = pure (coerce x)
- foldMap _ _ = mempty
-
- These definitions of ``foldMap`` and ``traverse`` are lazier than the ones we
- would otherwise derive, as they may produce results without inspecting their
- arguments at all.
-
- See also :ref:`deriving-functor`, :ref:`deriving-foldable`, and
- :ref:`deriving-traversable`.
-
-- Derived instances for empty data types are now substantially different
- than before. Here is an overview of what has changed. These examples will
- use a running example of ``data Empty a`` to describe what happens when an
- instance is derived for ``Empty``:
-
- - Derived ``Eq`` and ``Ord`` instances would previously emit code that used
- ``error``: ::
-
- instance Eq (Empty a) where
- (==) = error "Void =="
-
- instance Ord (Empty a) where
- compare = error "Void compare"
-
- Now, they emit code that uses maximally defined, lazier semantics: ::
-
- instance Eq (Empty a) where
- _ == _ = True
-
- instance Ord (Empty a) where
- compare _ _ = EQ
-
- - Derived ``Read`` instances would previous emit code that used
- ``parens``: ::
-
- instance Read (Empty a) where
- readPrec = parens pfail
-
- But ``parens`` forces parts of the parsed string that it doesn't need to.
- Now, the derived instance will not use ``parens`` (that it, parsing
- ``Empty`` will always fail, without reading *any* input): ::
-
- instance Read (Empty a) where
- readPrec = pfail
-
- - Derived ``Show`` instances would previously emit code that used
- ``error``: ::
-
- instance Show (Empty a) where
- showsPrec = error "Void showsPrec"
-
- Now, they emit code that inspects the argument. That is, if the argument
- diverges, then showing it will also diverge: ::
-
- instance Show (Empty a) where
- showsPrec _ x = case x of {}
-
- - Derived ``Functor``, ``Foldable``, ``Traversable``, ``Generic``,
- ``Generic1``, ``Lift``, and ``Data`` instances previously emitted code that
- used ``error``: ::
-
- instance Functor Empty where
- fmap = error "Void fmap"
-
- instance Foldable Empty where
- foldMap = error "Void foldMap"
-
- instance Traversable Empty where
- traverse = error "Void traverse"
-
- instance Generic (Empty a) where
- from = M1 (error "No generic representation for empty datatype Empty")
- to (M1 _) = error "No values for empty datatype Empty"
- -- Similarly for Generic1
-
- instance Lift (Empty a) where
- lift _ = error "Can't lift value of empty datatype Empty"
-
- instance Data a => Data (Empty a) where
- gfoldl _ _ _ = error "Void gfoldl"
- toConstr _ = error "Void toConstr"
- ...
-
- Now, derived ``Functor``, ``Traversable, ``Generic``, ``Generic1``,
- ``Lift``, and ``Data`` instances emit code which inspects their
- arguments: ::
-
- instance Functor Empty where
- fmap _ x = case x of {}
-
- instance Traversable Empty where
- traverse _ x = pure (case x of {})
-
- instance Generic (Empty a) where
- from x = M1 (case x of {})
- to (M1 x) = case x of {}
-
- -- Similarly for Generic1
-
- instance Lift (Empty a) where
- lift x = pure (case x of {})
-
- instance Data a => Data (Empty a) where
- gfoldl _ x = case x of {}
- toConstr x = case x of {}
- ...
-
- Derived ``Foldable`` instances now are maximally lazy: ::
-
- instance Foldable Empty where
- foldMap _ _ = mempty
-
-- Derived ``Foldable`` instances now derive custom definitions for ``null``
- instead of using the default one. This leads to asymptotically better
- performance for recursive types not shaped like cons-lists, and allows ``null``
- to terminate for more (but not all) infinitely large structures.
-
-- :ghc-flag:`-fsplit-sections` is now supported on x86_64 Windows and is on by default.
- See :ghc-ticket:`12913`.
-
-- Configure on Windows now supports the ``--enable-distro-toolchain``
- ``configure`` flag, which can be used to build a GHC using compilers on your
- ``PATH`` instead of using the bundled bindist. See :ghc-ticket:`13792`
-
-- GHC now enables :ghc-flag:`-fllvm-pass-vectors-in-regs` by default. This means
- that GHC will now use native vector registers to pass vector arguments across
- function calls.
-
-- The optional ``instance`` keyword is now usable in type family instance
- declarations. See :ghc-ticket:`13747`
-
-- Lots of other bugs. See `Trac <https://ghc.haskell.org/trac/ghc/query?status=closed&milestone=8.4.1&col=id&col=summary&col=status&col=type&col=priority&col=milestone&col=component&order=priority>`_
- for a complete list.
-
-- New flags :ghc-flag:`-fignore-optim-changes` and
- :ghc-flag:`-fignore-hpc-changes` allow GHC to reuse previously compiled
- modules even if they were compiled with different optimisation or HPC
- flags. These options are enabled by default by :ghc-flag:`--interactive`.
- See :ghc-ticket:`13604`
-
-Runtime system
-~~~~~~~~~~~~~~
-
-- Function ``hs_add_root()`` was removed. It was a no-op since GHC-7.2.1
- where module initialisation stopped requiring a call to ``hs_add_root()``.
-
-- Proper import library support added to GHC which can handle all of the libraries produced
- by ``dlltool``. The limitation of them needing to be named with the suffix
- ``.dll.a`` is also removed. See :ghc-ticket:`13606`, :ghc-ticket:`12499`,
- :ghc-ticket:`12498`
-
-- The GHCi runtime linker on Windows now supports the ``big-obj`` file format.
-
-- The runtime system's :ref:`native stack backtrace <backtrace-signal>` support
- on POSIX platforms is now triggered by ``SIGQUIT`` instead of ``SIGUSR2`` as
- it was in previous releases. This change is to bring GHC's behavior into
- compliance with the model set by the most Java virtual machine
- implementations.
-
-- The GHC runtime on Windows now uses Continue handlers instead of Vectorized
- handlers to trap exceptions. This change gives other exception handlers a chance
- to handle the exception before the runtime does. Furthermore The RTS flag
- :rts-flag:`--install-seh-handlers=<yes|no>` Can be used on Wndows to
- completely disable the runtime's handling of exceptions. See
- :ghc-ticket:`13911`, :ghc-ticket:`12110`.
-
-- The GHC runtime on Windows can now generate crash dumps on unhandled exceptions
- using the RTS flag :rts-flag:`--generate-crash-dumps`.
-
-- The GHCi runtime linker now avoid calling GCC to find libraries as much as possible by caching
- the list of search directories of GCC and querying the file system directly. This results in
- much better performance, especially on Windows.
-
-- The GHC runtime on Windows can now generate stack traces on unhandled exceptions.
- When running in GHCi more information is displayed about the symbols if available.
- This behavior can be controlled with the RTS flag `--generate-stack-traces=<yes|no>`.
-
-Template Haskell
-~~~~~~~~~~~~~~~~
-
-- Template Haskell now reifies data types with GADT syntax accurately.
- Previously, TH used heuristics to determine whether a data type
- should be reified using GADT syntax, which could lead to incorrect results,
- such as ``data T1 a = (a ~ Int) => MkT1`` being reified as a GADT and
- ``data T2 a where MkT2 :: Show a => T2 a`` *not* being reified as a GADT.
-
- In addition, reified GADT constructors now more accurately track the order in
- which users write type variables. Before, if you reified ``MkT`` as below: ::
-
- data T a where
- MkT :: forall b a. b -> T a
-
- Then the reified type signature of ``MkT`` would have been headed by
- ``ForallC [PlainTV a, PlainTV b]``. Now, reifying ``MkT`` will give a type
- headed by ``ForallC [PlainTV b, PlainTV a]``, as one would expect.
-
-
-- ``Language.Haskell.TH.FamFlavour``, which was deprecated in GHC 8.2,
- has been removed.
-
-``ghc`` library
-~~~~~~~~~~~~~~~
-
-- hsSyn Abstract Syntax Tree (AST) is now extensible via the mechanism described in `Trees that Grow <http://www.jucs.org/jucs_23_1/trees_that_grow/jucs_23_01_0042_0062_najd.pdf>`_
-
- The main change for users of the GHC API is that the AST is no longer indexed
- by the type used as the identifier, but by a specific index type, ::
-
- type GhcPs = GhcPass 'Parsed -- Old 'RdrName' type param
- type GhcRn = GhcPass 'Renamed -- Old 'Name' type param
- type GhcTc = GhcPass 'Typechecked -- Old 'Id' type para,
- type GhcTcId = GhcTc -- Old 'TcId' type param
-
- The simplest way to support the current GHC as well as earlier ones is to define ::
-
- #if MIN_VERSION_ghc(8,3,0)
- type ParseI = GhcPs
- type RenameI = GhcRn
- type TypecheckI = GhcTc
- #else
- type ParseI = RdrName
- type RenameI = Name
- type TypecheckI = Var
- #endif
-
- and then replace all hardcoded index types accordingly. For polymorphic types,
- the constraint ::
-
- #if MIN_VERSION_ghc(8,3,0)
- -- |bundle up the constraints required for a trees that grow pass
- type IsPass pass = (DataId pass, OutputableBndrId pass, SourceTextX pass)
- else
- type IsPass pass = (DataId pass, OutputableBndrId pass)
- #endif
-
- can be used.
-
-``base`` library
-~~~~~~~~~~~~~~~~
-
-- Blank strings can now be used as values for environment variables using the
- ``System.Environment.Blank`` module. See :ghc-ticket:`12494`
-
-- ``Data.Type.Equality.==`` is now a closed type family. It works for all kinds
- out of the box. Any modules that previously declared instances of this family
- will need to remove them. Whereas the previous definition was somewhat ad
- hoc, the behavior is now completely uniform. As a result, some applications
- that used to reduce no longer do, and conversely. Most notably, ``(==)`` no
- longer treats the ``*``, ``j -> k``, or ``()`` kinds specially; equality is
- tested structurally in all cases.
-
-Build system
-~~~~~~~~~~~~
-
-- ``dll-split`` has been removed and replaced with an automatic partitioning utility ``gen-dll``.
- This utility can transparently split and compile any DLLs that require this. Note that the ``rts`` and
- ``base`` can not be split at this point because of the mutual recursion between ``base`` and ``rts``.
- There is currently no explicit dependency between the two in the build system and such there is no way
- to notify ``base`` that the ``rts`` has been split, or vice versa.
- (see :ghc-ticket:`5987`).
-
-
-Included libraries
-------------------
-
-The package database provided with this distribution also contains a number of
-packages other than GHC itself. See the changelogs provided with these packages
-for further change information.
-
-.. ghc-package-list::
-
- libraries/array/array.cabal: Dependency of ``ghc`` library
- libraries/base/base.cabal: Core library
- libraries/binary/binary.cabal: Dependency of ``ghc`` library
- libraries/bytestring/bytestring.cabal: Deppendency of ``ghc`` library
- libraries/Cabal/Cabal/Cabal.cabal: Dependency of ``ghc-pkg`` utility
- libraries/containers/containers.cabal: Dependency of ``ghc`` library
- libraries/deepseq/deepseq.cabal: Dependency of ``ghc`` library
- libraries/directory/directory.cabal: Dependency of ``ghc`` library
- libraries/filepath/filepath.cabal: Dependency of ``ghc`` library
- compiler/ghc.cabal: The compiler itself
- libraries/ghci/ghci.cabal: The REPL interface
- libraries/ghc-boot/ghc-boot.cabal: Internal compiler library
- libraries/ghc-compact/ghc-compact.cabal: Core library
- libraries/ghc-prim/ghc-prim.cabal: Core library
- libraries/haskeline/haskeline.cabal: Dependency of ``ghci`` executable
- libraries/hpc/hpc.cabal: Dependency of ``hpc`` executable
- libraries/integer-gmp/integer-gmp.cabal: Core library
- libraries/mtl/mtl.cabal: Dependency of ``Cabal`` library
- libraries/parsec/parsec.cabal: Dependency of ``Cabal`` library
- libraries/process/process.cabal: Dependency of ``ghc`` library
- libraries/template-haskell/template-haskell.cabal: Core library
- libraries/text/text.cabal: Dependency of ``Cabal`` library
- libraries/time/time.cabal: Dependency of ``ghc`` library
- libraries/transformers/transformers.cabal: Dependency of ``ghc`` library
- libraries/unix/unix.cabal: Dependency of ``ghc`` library
- libraries/Win32/Win32.cabal: Dependency of ``ghc`` library
- libraries/xhtml/xhtml.cabal: Dependency of ``haddock`` executable
-
-Win32
-~~~~~
-
-.. attention::
-
- This release is a backwards incompatible release which corrects the type of
- certain APIs. See issue `#24 <https://github.com/haskell/win32/issues/24>`_.
diff --git a/docs/users_guide/8.4.2-notes.rst b/docs/users_guide/8.4.2-notes.rst
deleted file mode 100644
index e579e83c7c05042f6a4b16c93de9f71f4042582f..0000000000000000000000000000000000000000
--- a/docs/users_guide/8.4.2-notes.rst
+++ /dev/null
@@ -1,94 +0,0 @@
-.. _release-8-4-2:
-
-Release notes for version 8.4.2
-===============================
-
-TODO
-
-Highlights
-----------
-
-The highlights, since the 8.4.1 release, are:
-
-- TODO
-
-
-Full details
-------------
-
-
-Language
-~~~~~~~~
-
-- Fix a regression in which derived ``Read`` instances for record data types
- with field names ending with ``#`` (by way of :ghc-flag:`-XMagicHash`) would
- no longer parse valid output.
-
-Compiler
-~~~~~~~~
-
-
-Runtime system
-~~~~~~~~~~~~~~
-
-
-Template Haskell
-~~~~~~~~~~~~~~~~
-
-
-``ghc`` library
-~~~~~~~~~~~~~~~
-
-
-``base`` library
-~~~~~~~~~~~~~~~~
-
-- Add the ``readFieldHash`` function to ``GHC.Read`` which behaves like
- ``readField``, but for a field that ends with a ``#`` symbol.
-
-``integer-gmp`` library
-~~~~~~~~~~~~~~~~~~~~~~~
-
-- Define ``powModSecInteger``, a "secure" version of ``powModInteger`` using
- the ``mpz_powm_sec`` function.
-
-Build system
-~~~~~~~~~~~~
-
-
-Included libraries
-------------------
-
-The package database provided with this distribution also contains a number of
-packages other than GHC itself. See the changelogs provided with these packages
-for further change information.
-
-.. ghc-package-list::
-
- libraries/array/array.cabal: Dependency of ``ghc`` library
- libraries/base/base.cabal: Core library
- libraries/binary/binary.cabal: Dependency of ``ghc`` library
- libraries/bytestring/bytestring.cabal: Deppendency of ``ghc`` library
- libraries/Cabal/Cabal/Cabal.cabal: Dependency of ``ghc-pkg`` utility
- libraries/containers/containers.cabal: Dependency of ``ghc`` library
- libraries/deepseq/deepseq.cabal: Dependency of ``ghc`` library
- libraries/directory/directory.cabal: Dependency of ``ghc`` library
- libraries/filepath/filepath.cabal: Dependency of ``ghc`` library
- compiler/ghc.cabal: The compiler itself
- libraries/ghci/ghci.cabal: The REPL interface
- libraries/ghc-boot/ghc-boot.cabal: Internal compiler library
- libraries/ghc-compact/ghc-compact.cabal: Core library
- libraries/ghc-prim/ghc-prim.cabal: Core library
- libraries/haskeline/haskeline.cabal: Dependency of ``ghci`` executable
- libraries/hpc/hpc.cabal: Dependency of ``hpc`` executable
- libraries/integer-gmp/integer-gmp.cabal: Core library
- libraries/mtl/mtl.cabal: Dependency of ``Cabal`` library
- libraries/parsec/parsec.cabal: Dependency of ``Cabal`` library
- libraries/process/process.cabal: Dependency of ``ghc`` library
- libraries/template-haskell/template-haskell.cabal: Core library
- libraries/text/text.cabal: Dependency of ``Cabal`` library
- libraries/time/time.cabal: Dependency of ``ghc`` library
- libraries/transformers/transformers.cabal: Dependency of ``ghc`` library
- libraries/unix/unix.cabal: Dependency of ``ghc`` library
- libraries/Win32/Win32.cabal: Dependency of ``ghc`` library
- libraries/xhtml/xhtml.cabal: Dependency of ``haddock`` executable
diff --git a/docs/users_guide/index.rst b/docs/users_guide/index.rst
index 7f42dca802bb453875a45c319b225bfebdf9cc5f..b1b0141d25059c057439dd9e6202c76eb3b20d5b 100644
--- a/docs/users_guide/index.rst
+++ b/docs/users_guide/index.rst
@@ -12,7 +12,6 @@ Contents:
license
intro
- 8.4.2-notes
8.6.1-notes
ghci
runghc