diff options
Diffstat (limited to 'docs/users_guide/8.12.1-notes.rst')
| -rw-r--r-- | docs/users_guide/8.12.1-notes.rst | 83 |
1 files changed, 44 insertions, 39 deletions
diff --git a/docs/users_guide/8.12.1-notes.rst b/docs/users_guide/8.12.1-notes.rst index eb72ca9bde..b98b1f283b 100644 --- a/docs/users_guide/8.12.1-notes.rst +++ b/docs/users_guide/8.12.1-notes.rst @@ -79,12 +79,15 @@ Language * 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. + 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 allows users to manually define the specificity of type variable binders. By marking a variable with braces ``{tyvar}`` or ``{tyvar :: kind}``, @@ -110,31 +113,33 @@ Runtime system Template Haskell ~~~~~~~~~~~~~~~~ - - Implement the Overloaded Quotations proposal (#246). The type of all quotation - forms have now been generalised in terms of a minimal interface necessary for the - implementation rather than the overapproximation of the ``Q`` monad. +- 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. +- 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. (!2288) +- 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 :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 ``|)``: :: +- 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 - ... |) + (| untilA (increment -< x + y) do + within 0.5 -< x + ... |) ``ghc-prim`` library ~~~~~~~~~~~~~~~~~~~~ @@ -142,28 +147,28 @@ Arrow notation ``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: :: +- 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]) + 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: :: +- 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 + 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. + 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`` @@ -196,7 +201,7 @@ for further change information. 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 ``haskeline`` 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 |