users guide: Drop 9.0 release notes

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diff --git a/docs/users_guide/9.0.1-notes.rst b/docs/users_guide/9.0.1-notes.rst
deleted file mode 100644
index 95e9852e61..0000000000
--- a/docs/users_guide/9.0.1-notes.rst
+++ /dev/null
@@ -1,474 +0,0 @@
-.. _release-9-0-1:
-
-Version 9.0.1
-==============
-
-The significant changes to the various parts of the compiler are listed in the
-following sections.
-
-
-Highlights
-----------
-
-* The :extension:`LinearTypes` extension enables linear function syntax
-  ``a %1 -> b``, as described in the `Linear Types GHC proposal
-  <https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0111-linear-types.rst>`__.
-
-  The GADT syntax can be used to define data types with linear and nonlinear fields.
-
-  This extension is considered experimental: it doesn't implement the full proposal yet and the details
-  are subject to change.
-
-* NCG
-
-  - The linear register allocator saw improvements reducing the number
-    of redundant move instructions. Rare edge cases can see double
-    digit improvements in runtime for inner loops.
-
-    In the mean this improved runtime by about 0.8%. For details
-    see ticket :ghc-ticket:`17823`.
-
-* Pattern-Match Coverage Checking
-
-  - The revamp of the pattern-match coverage checker that started in 8.10 concludes with this release and implements the
-    novel `*Lower Your Guards* <https://www.microsoft.com/en-us/research/uploads/prod/2020/03/lyg.pdf>`_ algorithm.
-  - Compared to 8.10, end users might notice improvements to "long-distance information": ::
-
-      f True = 1
-      f x    = ... case x of { False -> 2; True -> 3 } ...
-
-    GHC is now able to detect the case alt returning 3 as redundant.
-  - Some more performance improvements in edge cases.
-
-* Windows: Use the large address space allocator.
-
-  This improves runtime but causes increased memory usage on Windows versions
-  older than Win 8.1/Server 2012.
-
-* Big-number support
-
-  - GHC now relies on a new "ghc-bignum" package to provide Integer/Natural
-    implementations. This package supports the following backends:
-
-    - gmp: adapted from integer-gmp package that was used before
-    - native: new Haskell implementation, faster than integer-simple which is
-      not used anymore
-
-  - All backends now use the same representation for big numbers (the one that
-    was previously used only by integer-gmp). It led to several compiler
-    simplifications, performance improvements and bug fixes (e.g.
-    :ghc-ticket:`15262`, :ghc-ticket:`15286`).
-
-  - All backends must provide exactly the same set of functions with
-    deterministic results so that they can be tested one against the other (they
-    can only differ in performance). As a consequence, some functions that were
-    only provided by integer-gmp (prime test, secure powmod, etc.) are no longer
-    provided by ghc-bignum. Note that other packages (e.g. hgmp) provide these
-    functions.
-
-  - For now GHC still doesn't allow dynamic selection of the ghc-bignum backend
-    to use.
-
-* Breaking change: Template Haskell splices now act as separation points
-  between constraint solving passes. It is no longer possible to use
-  an instance of a class before a splice and define that instance after a splice.
-  For example, this code now reports a missing instance for ``C Bool``: ::
-
-      class C a where foo :: a
-      bar :: Bool
-      bar = foo
-      $(return [])
-      instance C Bool where foo = True
-
- * Support for 32-bit Windows has officially been dropped as Microsoft has
-   formally discontinued new 32-bit Windows 10 releases in 2020. See
-   :ghc-ticket:`18487` for details.
-
-
-Full details
-------------
-
-Language
-~~~~~~~~
-
-* Record field selectors are now given type signatures that preserve the
-  user-written order of quantified type variables. Moreover, field selector
-  type signatures no longer make inferred type variables available for explicit
-  type application. See :ref:`field-selectors-and-type-applications` for more
-  details.
-
-  In certain situations, this will constitute a breaking change as this can
-  affect :extension:`TypeApplications`. For instance, given the following
-  definitions: ::
-
-    {-# LANGUAGE PolyKinds #-}
-
-    newtype P a = MkP { unP :: Proxy a }
-
-    newtype N :: Type -> Type -> Type where
-      MkN :: forall b a. { unN :: Either a b } -> N a b
-
-  Previous versions of GHC would give the following types to ``unP`` and
-  ``unN``: ::
-
-    unP :: forall k (a :: k). P a -> Proxy a
-    unN :: forall a b. N a b -> Either a b
-
-  GHC will now give them the following types instead: ::
-
-    unP :: forall {k} (a :: k). P a -> Proxy a
-    unN :: forall b a. N a b -> Either a b
-
-* In obscure scenarios, GHC now rejects programs it previously accepted, but
-  with unhelpful types. For example, if (with ``-XPartialTypeSignatures``) you
-  were to write ``x :: forall (f :: forall a (b :: a -> Type). b _). f _``, GHC previously
-  would have accepted ``x``, but its type would have involved the mysterious ``Any``
-  internal type family. Now, GHC rejects, explaining the situation.
-
-* GHC now more faithfully implements the instance-lookup scheme described with
-  :extension:`QuantifiedConstraints`. Previous bugs meant that programs like this
-  were accepted::
-
-    data T (c :: Type -> Constraint)
-    instance (forall h. c h => Functor h) => Functor (T c)
-    instance (forall h. c h => Applicative h) => Applicative (T c)
-
-  Note that in the instance declaration for ``Applicative (T c)``, we cannot prove
-  ``Functor (T c)``, because the quantified constraint shadows the global instance.
-  There is an easy workaround, though: just include ``Functor (T c)`` as an assumption. ::
-
-    instance (forall h. c h => Applicative h, Functor (T c)) => Applicative (T c)
-
-  There is a chance we will tweak the lookup scheme in the future, to make this
-  workaround unnecessary.
-
-* GHC now consistently does eager instantiation during type inference.
-  As a consequence, visible type application (VTA) now only works when
-  the head of the application is:
-
-  * A variable
-  * An expression with a type signature
-
-  For example ``(let x = blah in id) @Bool True`` no longer typechecks.
-  You should write ``let x = blah in id @Bool True`` instead.
-
-  This change prepares the way for `Quick Look impredicativity
-  <https://gitlab.haskell.org/ghc/ghc/issues/18126>`_.
-
-* GHC now implements simplified subsumption, as described in `GHC Proposal #287 <https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0287-simplify-subsumption.rst>`__.
-  This change simplifies the type system, and prevents the possibility of GHC
-  silently changing the semantics of user programs, but it does mean that some libraries
-  may need eta-expansion to typecheck.  More info here: :ref:`simple-subsumption`.
-
-  This change also prepares the way for Quick Look impredicativity.
-
-* GHC now allows users to manually define the specificity of type variable
-  binders. By marking a variable with braces ``{tyvar}`` or ``{tyvar :: kind}``,
-  it becomes inferred despite appearing in a type signature. This feature
-  effectively allows users to choose which variables can or can't be
-  instantiated through visible type application. More information can be found
-  here: :ref:`Manually-defining-inferred-variables`.
-
-* GADT constructor types now properly adhere to :ref:`forall-or-nothing`. As
-  a result, GHC will now reject some GADT constructors that previous versions
-  of GHC would accept, such as the following: ::
-
-    data T where
-      MkT1 :: (forall a. a -> b -> T)
-      MkT2 :: (forall a. a -> T)
-
-  ``MkT1`` and ``MkT2`` are rejected because the lack of an outermost
-  ``forall`` triggers implicit quantification, making the explicit ``forall``\ s
-  nested. Furthermore, GADT constructors do not permit the use of nested
-  ``forall``\ s, as explained in :ref:`formal-gadt-syntax`.
-
-  In addition to rejecting nested ``forall``\ s, GHC is now more stringent about
-  rejecting uses of nested *contexts* in GADT constructors. For example, the
-  following example, which previous versions of GHC would accept, is now
-  rejected: ::
-
-    data U a where
-      MkU :: (Show a => U a)
-
-* GHC more strictly enforces the rule that the type in the top of an instance
-  declaration is not permitted to contain nested ``forall``\ s or contexts, as
-  documented in :ref:`formal-instance-syntax`. For example, the following
-  examples, which previous versions of GHC would accept, are now rejected: ::
-
-    instance (forall a. C a) where ...
-    instance (Show a => C a) where ...
-
-  In addition, GHC now enforces the rule that the types in ``deriving`` clauses
-  and ``via`` types (for instances derived with :extension:`DerivingVia`)
-  cannot contain nested ``forall``\ s or contexts. For example, the following
-  examples, which previous versions of GHC would accept, are now rejected: ::
-
-    data T = MkT deriving (C1, (forall x. C2 x))
-    deriving via (forall x. V x) instance C (S x)
-
-* A new language extension :extension:`QualifiedDo` is implemented, allowing
-  to qualify a do block to control which operations to use for desugaring do
-  syntax. ::
-
-    {-# LANGUAGE QualifiedDo #-}
-    import qualified SomeModule as M
-
-    f x = M.do           -- desugars to:
-      y <- M.return x    -- M.return x M.>>= \y ->
-      M.return y         -- M.return y M.>>
-      M.return y         -- M.return y
-
-  See :ref:`qualified-do-notation` for more details.
-
-* :extension:`LexicalNegation` is a new extension that detects whether the
-  minus sign stands for negation during lexical analysis by checking for the
-  surrounding whitespace: ::
-
-    a = x - y  -- subtraction
-    b = f -x   -- negation
-
-    f = (- x)  -- operator section
-    c = (-x)   -- negation
-
-* The behavior of :extension:`NegativeLiterals` changed, and now we require
-  that a negative literal must not be preceded by a closing token (see
-  `GHC Proposal #229 <https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0229-whitespace-bang-patterns.rst>`__
-  for the definition of a closing token). In other words, we parse ``f -123``
-  as ``f (-123)``, but ``x-123`` as ``(-) x 123``. Before this amendment,
-  :extension:`NegativeLiterals` caused ``x-123`` to be parsed as ``x(-123)``.
-
-Compiler
-~~~~~~~~
-
-- A new flag :ghc-flag:`-flink-rts` to enable linking the RTS when linking
-  shared libraries.
-
-- The :ghc-flag:`-Wnoncanonical-monad-instances` and
-  :ghc-flag:`-Wnoncanonical-monoid-instances` warnings are now enabled by
-  default, as proposed in `GHC proposal #314
-  <https://github.com/ghc-proposals/ghc-proposals/pull/314>`_
-
-GHCi
-~~~~
-
-- The ``:script`` command now allows for file names that contain spaces to
-  passed as arguments: either by enclosing the file names in double quotes or by
-  escaping spaces in file names with a backslash. (:ghc-ticket:`18027`)
-
-- The GHCi debugger syntax ``:break <qualified.name>`` now allows to set
-  breakpoints on all functions. The restrictions ``top-Level`` and ``exported``
-  have been removed. Hence it's now possible to use this syntax to set
-  breakpoints on functions defined in nested ``where`` or ``let`` clauses.
-
-Runtime system
-~~~~~~~~~~~~~~
-
-- :rts-flag:`-N` without a count now tries to respect the number of processors
-  in the process's affinity mask, making GHC's behavior more predictable in
-  containerized settings (:ghc-ticket:`14781`).
-
-- Support for Windows Vista has been dropped. GHC-compiled programs now require
-  Windows 7 or later.
-
-- Windows now uses the large address space allocator by default.
-  In extreme cases we saw improvements by up to 3% decreased runtime.
-
-  The downside is that haskell apps run on older (Pre Win-8.1/Server 2012)
-  systems will have higher memory footprints.
-
-Template Haskell
-~~~~~~~~~~~~~~~~
-
-- Implement the `Overloaded Quotations proposal (#246) <https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0246-overloaded-bracket.rst>`_.
-  The type of all quotation forms have now been generalised in terms of a
-  minimal interface necessary (the ``Quote`` type class) for the
-  implementation rather than the overapproximation of the ``Q`` monad.
-
-- Template Haskell quotes now handle fixity declarations in ``let`` and
-  ``where`` bindings properly. Previously, such fixity declarations would
-  be dropped when quoted due to a Template Haskell bug.
-
-- The ``-XTemplateHaskellQuotes`` extension now allows nested splices as nested
-  splices do not lead directly to compile-time evaluation. (Merge request
-  `!2288 <https://gitlab.haskell.org/ghc/ghc/-/merge_requests/2288>`_)
-
-Arrow notation
-~~~~~~~~~~~~~~
-
-- When combined with :extension:`Arrows`, the :extension:`LambdaCase` extension
-  now additionally allows ``\case`` syntax to be used as a command in ``proc``
-  notation.
-
-- When combined with :extension:`Arrows`, the effects of the
-  :extension:`BlockArguments` extension now also apply to applications of
-  arrow control operators in ``(|`` banana brackets ``|)``: ::
-
-    (| untilA (increment -< x + y) do
-         within 0.5 -< x
-         ... |)
-
-Haddock
-~~~~~~~
-
-- Parsing is now more robust to insufficiently indented Haddock comments::
-
-    class C a where
-      f :: a -> a
-    -- ^ This comment used to trigger a parse error
-      g :: a -> a
-
-- :ghc-flag:`-Winvalid-haddock` is a new warning that reports discarded Haddock
-  comments that cannot be associated with AST elements::
-
-    myValue =
-      -- | Invalid (discarded) comment in an expression
-      2 + 2
-
-- When faced with several comments for a data constructor or a data constructor
-  field, Haddock now picks the first one instead of the last one.  The
-  extraneous comment is reported as invalid when :ghc-flag:`-Winvalid-haddock`
-  is enabled::
-
-    data T
-      -- | First comment
-      = MkT
-      -- ^ Second comment (rejected)
-
-
-- Haddock is now more relaxed about the placement of comments in types relative
-  to the function arrow ``->``, allowing more formatting styles::
-
-    f :: Int ->   -- ^ comment on Int (no longer a parse error)
-         Bool     -- ^ comment on Bool
-
-- Haddock can now parse the documentation comment for the first declaration in
-  a module without a module header (:ghc-ticket:`17561`)::
-
-    -- | This comment used to trigger a parse error
-    main = putStrLn "Hello"
-
-``base`` library
-~~~~~~~~~~~~~~~~
-
-- ``Foreign.ForeignPtr.withForeignPtr`` is now less aggressively optimised,
-  avoiding the unsoundness issue reported in
-  :ghc-ticket:`17760` in exchange for a small amount of additional allocation.
-
-  If your application is impacted significantly by this change and the
-  continuation given to ``withForeignPtr`` will not *provably* diverge (via
-  throwing of an exception or looping) then the previous optimisation behavior
-  can be recovered by instead using ``GHC.ForeignPtr.unsafeWithForeignPtr``.
-
-
-``ghc-prim`` library
-~~~~~~~~~~~~~~~~~~~~
-
-- Add a known-key ``cstringLength#`` to ``GHC.CString`` that is eligible
-  for constant folding by a built-in rule.
-
-- A new primop, ``keepAlive#``, has been introduced to replace ``touch#`` in
-  controlling object lifetime without the soundness issues affecting the latter
-  (see :ghc-ticket:`17760`)
-
-``ghc`` library
-~~~~~~~~~~~~~~~
-
-- The type of the ``getAnnotations`` function has changed to better reflect
-  the fact that it returns two different kinds of annotations, those on
-  names and those on modules: ::
-
-     getAnnotations :: Typeable a
-                    => ([Word8] -> a) -> ModGuts
-                    -> CoreM (ModuleEnv [a], NameEnv [a])
-
-- The meaning of the ``hs_fixds`` field of ``HsGroup`` has changed slightly.
-  It now only contains fixity signatures defined for top-level declarations
-  and class methods defined *outside* of the class itself. Previously,
-  ``hs_fixds`` would also contain fixity signatures for class methods defined
-  *inside* the class, such as the fixity signature for ``m`` in the following
-  example: ::
-
-    class C a where
-      infixl 4 `m`
-      m :: a -> a -> a
-
-  If you wish to attain the previous behavior of ``hs_fixds``, use the new
-  ``hsGroupTopLevelFixitySigs`` function, which collects all top-level fixity
-  signatures, including those for class methods defined inside classes.
-
-- The ``Exception`` module was boiled down acknowledging the existence of
-  the ``exceptions`` dependency. In particular, the ``ExceptionMonad``
-  class is not a proper class anymore, but a mere synonym for ``MonadThrow``,
-  ``MonadCatch``, ``MonadMask`` (all from ``exceptions``) and ``MonadIO``.
-  All of ``g*``-functions from the module (``gtry``, ``gcatch``, etc.) are
-  erased, and their ``exceptions``-alternatives are meant to be used in the
-  GHC code instead.
-
-- ``parseModule`` is now the only parser entry point that deals with Haddock
-  comments. The other entry points (``parseDeclaration``, ``parseExpression``,
-  etc) do not insert the Haddock comments into the AST.
-
-``base`` library
-~~~~~~~~~~~~~~~~
-
-- ``ForeignPtrContents`` has a new nullary data constructor ``FinalPtr``.
-  ``FinalPtr`` is intended for turning a primitive string literal into a
-  ``ForeignPtr``.  Unlike ``PlainForeignPtr``, ``FinalPtr`` does not have
-  a finalizer. Replacing ``PlainForeignPtr`` that has ``NoFinalizers`` with
-  ``FinalPtr`` reduces allocations, reduces the size of compiled binaries,
-  and unlocks important Core-to-Core optimizations. ``FinalPtr`` will be used
-  in an upcoming ``bytestring`` release to improve the performance of
-  ``ByteString`` literals created with ``OverloadedStrings``.
-
-Build system
-~~~~~~~~~~~~
-
-Bootstrapping requirements
---------------------------
-
-- GHC now requires a C compiler which supports
-  ``__atomic_op_n`` builtins. This raises the requirement for GCC to 4.7.
-
-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:   Dependency of ``ghc`` library
-    libraries/Cabal/Cabal/Cabal.cabal:       Dependency of ``ghc-pkg`` utility
-    libraries/containers/containers/containers.cabal:   Dependency of ``ghc`` library
-    libraries/deepseq/deepseq.cabal:         Dependency of ``ghc`` library
-    libraries/directory/directory.cabal:     Dependency of ``ghc`` library
-    libraries/exceptions/exceptions.cabal:   Dependency of ``ghc`` and ``haskeline`` 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-boot-th/ghc-boot-th.cabal: Internal compiler library
-    libraries/ghc-compact/ghc-compact.cabal: Core library
-    libraries/ghc-heap/ghc-heap.cabal:       GHC heap-walking 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/libiserv/libiserv.cabal:       Internal compiler library
-    libraries/mtl/mtl.cabal:                 Dependency of ``Cabal`` library
-    libraries/parsec/parsec.cabal:           Dependency of ``Cabal`` library
-    libraries/pretty/pretty.cabal:           Dependency of ``ghc`` library
-    libraries/process/process.cabal:         Dependency of ``ghc`` library
-    libraries/stm/stm.cabal:                 Dependency of ``haskeline`` library
-    libraries/template-haskell/template-haskell.cabal:     Core library
-    libraries/terminfo/terminfo.cabal:       Dependency of ``haskeline`` 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/release-notes.rst b/docs/users_guide/release-notes.rst
index 92d4277a67..34cceb89d1 100644
--- a/docs/users_guide/release-notes.rst
+++ b/docs/users_guide/release-notes.rst
@@ -4,5 +4,4 @@ Release notes
 .. toctree::
    :maxdepth: 1
 
-   9.0.1-notes
    9.2.1-notes