From 2b1faea90dff1ad743925eb5a0b552a11c514349 Mon Sep 17 00:00:00 2001
From: Vladislav Zavialov <vlad.z.4096@gmail.com>
Date: Sat, 9 Mar 2024 20:38:29 +0300
Subject: [PATCH] docs: Update info on TypeAbstractions
* Mention TypeAbstractions in 9.10.1-notes.rst
* Set the status to "Experimental".
* Add a "Since: GHC 9.x" comment to each section.
---
docs/users_guide/9.10.1-notes.rst | 14 ++++++++++++++
docs/users_guide/exts/type_abstractions.rst | 8 +++++++-
2 files changed, 21 insertions(+), 1 deletion(-)
diff --git a/docs/users_guide/9.10.1-notes.rst b/docs/users_guide/9.10.1-notes.rst
index 38bbcae39f89..cb87ee167cc9 100644
--- a/docs/users_guide/9.10.1-notes.rst
+++ b/docs/users_guide/9.10.1-notes.rst
@@ -124,6 +124,20 @@ Language
The extension is enabled by default, establishing the usual behavior.
+- In accordance with GHC Proposal `#448 <https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0448-type-variable-scoping.rst>`_,
+ the :extension:`TypeAbstractions` extension has been extended to support
+ ``@``-binders in lambdas and function equations::
+
+ id :: forall a. a -> a
+ id @t x = x :: t
+ -- ^^ @-binder in a function equation
+
+ e = higherRank (\ @t -> ... )
+ -- ^^ @-binder in a lambda
+
+ This feature is an experimental alternative to :extension:`ScopedTypeVariables`,
+ see the :ref:`type-abstractions-in-functions` section.
+
Compiler
~~~~~~~~
diff --git a/docs/users_guide/exts/type_abstractions.rst b/docs/users_guide/exts/type_abstractions.rst
index 1b55c2b60257..925048e62b56 100644
--- a/docs/users_guide/exts/type_abstractions.rst
+++ b/docs/users_guide/exts/type_abstractions.rst
@@ -6,7 +6,7 @@ Type abstractions
:since: 9.8.1
- :status: Partially implemented
+ :status: Experimental
Allow the use of type abstraction syntax.
@@ -22,6 +22,8 @@ and `#425 <https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/
Type Abstractions in Patterns
-----------------------------
+**Since:** GHC 9.2
+
The type abstraction syntax can be used in patterns that match a data
constructor. The syntax can't be used with record patterns or infix patterns.
This is useful in particular to bind existential type variables associated with
@@ -99,6 +101,8 @@ matched, rather than ever referring to a variable from an outer scope. Type wild
Type Abstractions in Functions
------------------------------
+**Since:** GHC 9.10
+
Type abstraction syntax can be used in lambdas and function left-hand sides to
bring into scope type variables associated with invisible ``forall``.
For example::
@@ -200,6 +204,8 @@ At the moment, an ``@``-binder is valid only in a limited set of circumstances:
Invisible Binders in Type Declarations
--------------------------------------
+**Since:** GHC 9.8
+
Syntax
~~~~~~
--
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