diff --git a/.github/workflows/haskell-ci.yml b/.github/workflows/haskell-ci.yml
index 53f7e2a..382e1c6 100644
--- a/.github/workflows/haskell-ci.yml
+++ b/.github/workflows/haskell-ci.yml
@@ -204,6 +204,8 @@ jobs:
           if [ $((HCNUMVER < 90800)) -ne 0 ] ; then echo "package hpqtypes-extras" >> cabal.project ; fi
           if [ $((HCNUMVER < 90800)) -ne 0 ] ; then echo "    ghc-options: -j4" >> cabal.project ; fi
           cat >> cabal.project <<EOF
+          package hpqtypes-extras
+            ghc-options: -Werror
           EOF
           cat cabal.project
           cat cabal.project.local
diff --git a/cabal.haskell-ci b/cabal.haskell-ci
index 4dada4a..fd49532 100644
--- a/cabal.haskell-ci
+++ b/cabal.haskell-ci
@@ -3,3 +3,7 @@ doctest:        False
 tests:          True
 postgresql:     True
 installed:      -all
+
+raw-project
+  package hpqtypes-extras
+    ghc-options: -Werror
diff --git a/src/Database/PostgreSQL/PQTypes/SQL/Builder.hs b/src/Database/PostgreSQL/PQTypes/SQL/Builder.hs
index 1e5af6b..52fda10 100644
--- a/src/Database/PostgreSQL/PQTypes/SQL/Builder.hs
+++ b/src/Database/PostgreSQL/PQTypes/SQL/Builder.hs
@@ -170,7 +170,6 @@ import Data.List
 import Data.Maybe
 import Data.Monoid.Utils
 import Data.String
-import Data.Typeable
 import Database.PostgreSQL.PQTypes
 
 class Sqlable a where
@@ -204,7 +203,7 @@ data AscDesc a = Asc a | Desc a
   deriving (Eq, Show)
 
 data Multiplicity a = Single a | Many [a]
-  deriving (Eq, Ord, Show, Typeable)
+  deriving (Eq, Ord, Show)
 
 -- | 'SqlCondition' are clauses that are part of the WHERE block in
 -- SQL statements. Each statement has a list of conditions, all of
@@ -215,7 +214,7 @@ data Multiplicity a = Single a | Many [a]
 data SqlCondition
   = SqlPlainCondition SQL
   | SqlExistsCondition SqlSelect
-  deriving (Typeable, Show)
+  deriving (Show)
 
 instance Sqlable SqlCondition where
   toSQLCommand (SqlPlainCondition a) = a
diff --git a/src/Database/PostgreSQL/PQTypes/Utils/NubList.hs b/src/Database/PostgreSQL/PQTypes/Utils/NubList.hs
index c7a0c3b..86af034 100644
--- a/src/Database/PostgreSQL/PQTypes/Utils/NubList.hs
+++ b/src/Database/PostgreSQL/PQTypes/Utils/NubList.hs
@@ -5,8 +5,6 @@ module Database.PostgreSQL.PQTypes.Utils.NubList
   , overNubList
   ) where
 
-import Data.Typeable
-
 import Data.Semigroup qualified as SG
 import Data.Set qualified as Set
 import Text.Read qualified as R
@@ -21,7 +19,7 @@ import Text.Read qualified as R
 -- | NubList : A de-duplicated list that maintains the original order.
 newtype NubList a
   = NubList {fromNubList :: [a]}
-  deriving (Eq, Typeable)
+  deriving (Eq)
 
 -- NubList assumes that nub retains the list order while removing duplicate
 -- elements (keeping the first occurence). Documentation for "Data.List.nub"
diff --git a/test/Main.hs b/test/Main.hs
index 679d448..f6cd521 100644
--- a/test/Main.hs
+++ b/test/Main.hs
@@ -28,7 +28,6 @@ import Test.Tasty.HUnit
 import Test.Tasty.Options
 
 newtype ConnectionString = ConnectionString String
-  deriving (Typeable)
 
 instance IsOption ConnectionString where
   defaultValue =