From 2a257b5317b34bfa940e8daa8e7afd4f0643fd86 Mon Sep 17 00:00:00 2001
From: Edsko de Vries <edsko@well-typed.com>
Date: Tue, 15 Oct 2024 13:54:37 +0200
Subject: [PATCH] Document required dependencies and extensions

---
 large-records/CHANGELOG.md              |  3 ++-
 large-records/src/Data/Record/Plugin.hs | 28 +++++++++++++++++++++++++
 2 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/large-records/CHANGELOG.md b/large-records/CHANGELOG.md
index 55e2568..fdb617d 100644
--- a/large-records/CHANGELOG.md
+++ b/large-records/CHANGELOG.md
@@ -2,8 +2,9 @@
 
 ## 0.4.2 -- 2024-10-15
 
-* Support `primitive-0.7.3` (#159, Isaac Elliott)
+* Support `primitive-0.7.3` (#159, Isaac Elliott).
 * Plugin idempotence (#159, Isaac Elliott).
+* Document required additional dependencies and language extensions (#161).
 
 Note: if your code imports `Data.Plugin.Record` only for the `largeRecord`
 identifier used in the `ANN` annotations, this import is no longer required
diff --git a/large-records/src/Data/Record/Plugin.hs b/large-records/src/Data/Record/Plugin.hs
index f06d351..e731be1 100644
--- a/large-records/src/Data/Record/Plugin.hs
+++ b/large-records/src/Data/Record/Plugin.hs
@@ -14,6 +14,34 @@
 --
 -- See 'LargeRecordOptions' for the list of all possible annotations.
 --
+-- = Dependencies
+--
+-- In addition to the dependency on @large-records@, you will also need to add
+-- dependencies
+-- on [large-generics](http://hackage.haskell.org/package/large-generics)
+-- and [record-hasfield](http://hackage.haskell.org/package/record-hasfield).
+--
+-- = Language extensions
+--
+-- The plugin depends on a number of language extensions. If you are using
+-- GHC2021, you will need enable:
+--
+-- > {-# LANGUAGE DataKinds             #-}
+-- > {-# LANGUAGE TypeFamilies          #-}
+-- > {-# LANGUAGE UndecidableInstances  #-}
+--
+-- If you are using Haskell2010, you need to enable:
+--
+-- > {-# LANGUAGE ConstraintKinds       #-}
+-- > {-# LANGUAGE DataKinds             #-}
+-- > {-# LANGUAGE FlexibleInstances     #-}
+-- > {-# LANGUAGE GADTs                 #-}
+-- > {-# LANGUAGE MultiParamTypeClasses #-}
+-- > {-# LANGUAGE ScopedTypeVariables   #-}
+-- > {-# LANGUAGE TypeFamilies          #-}
+-- > {-# LANGUAGE TypeOperators         #-}
+-- > {-# LANGUAGE UndecidableInstances  #-}
+--
 -- = Usage with @record-dot-preprocessor@
 --
 -- The easiest way to use both plugins together is to do