diff --git a/message-index/messages/GHC-16437/deriving_gadt/after/Deriving_gadt.hs b/message-index/messages/GHC-16437/deriving_gadt/after/Deriving_gadt.hs
new file mode 100644
index 00000000..08095b52
--- /dev/null
+++ b/message-index/messages/GHC-16437/deriving_gadt/after/Deriving_gadt.hs
@@ -0,0 +1,9 @@
+{-# LANGUAGE GADTs #-}
+{-# LANGUAGE StandaloneDeriving #-}
+
+module Deriving_gadt where
+
+data T a b where
+     Mk :: Int -> b -> T Int b
+
+deriving instance Functor (T a)
diff --git a/message-index/messages/GHC-16437/deriving_gadt/before/Deriving_gadt.hs b/message-index/messages/GHC-16437/deriving_gadt/before/Deriving_gadt.hs
new file mode 100644
index 00000000..9498d993
--- /dev/null
+++ b/message-index/messages/GHC-16437/deriving_gadt/before/Deriving_gadt.hs
@@ -0,0 +1,5 @@
+module Deriving_gadt where
+
+data T a b where
+     Mk :: Int -> b -> T Int b
+     deriving (Functor)
diff --git a/message-index/messages/GHC-16437/deriving_gadt/index.md b/message-index/messages/GHC-16437/deriving_gadt/index.md
new file mode 100644
index 00000000..e5613854
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+++ b/message-index/messages/GHC-16437/deriving_gadt/index.md
@@ -0,0 +1,3 @@
+---
+title: Attempt at using deriving clause with GADT.
+---
diff --git a/message-index/messages/GHC-16437/higher_rank/after/Higher_rank.hs b/message-index/messages/GHC-16437/higher_rank/after/Higher_rank.hs
new file mode 100644
index 00000000..bc28a09c
--- /dev/null
+++ b/message-index/messages/GHC-16437/higher_rank/after/Higher_rank.hs
@@ -0,0 +1,5 @@
+
+module Higher_rank where
+
+-- unfortunately we just need a rank 1 type
+data Bad = MkBad a deriving Eq
diff --git a/message-index/messages/GHC-16437/higher_rank/before/Higher_rank.hs b/message-index/messages/GHC-16437/higher_rank/before/Higher_rank.hs
new file mode 100644
index 00000000..6d3947bd
--- /dev/null
+++ b/message-index/messages/GHC-16437/higher_rank/before/Higher_rank.hs
@@ -0,0 +1,5 @@
+{-# LANGUAGE RankNTypes #-}
+
+module Higher_rank where
+
+data Bad = MkBad (forall a. a) deriving Eq
diff --git a/message-index/messages/GHC-16437/higher_rank/index.md b/message-index/messages/GHC-16437/higher_rank/index.md
new file mode 100644
index 00000000..2f78ca63
--- /dev/null
+++ b/message-index/messages/GHC-16437/higher_rank/index.md
@@ -0,0 +1,3 @@
+---
+title: Use of higher-rank types with a derving clause.
+---
diff --git a/message-index/messages/GHC-16437/index.md b/message-index/messages/GHC-16437/index.md
new file mode 100644
index 00000000..5dcb7b87
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+++ b/message-index/messages/GHC-16437/index.md
@@ -0,0 +1,11 @@
+---
+title: Bad Constructor used with deriving clause
+summary: The deriving mechanism expects constructors of a particular form. When the constructors do not comport to this form, this error is thrown.
+severity: error
+introduced: 9.6.1
+---
+
+    • Can't make a derived instance of ‘Functor (T a)’:
+        Constructor ‘Mk’ is a GADT
+    • In the data declaration for ‘T’
+    Suggested fix: Use a standalone deriving declaration instead