diff --git a/src/Disco/Desugar.hs b/src/Disco/Desugar.hs
index 7319a60c..e61be7ba 100644
--- a/src/Disco/Desugar.hs
+++ b/src/Disco/Desugar.hs
@@ -1,3 +1,7 @@
+{-# OPTIONS_GHC -fno-warn-unrecognised-pragmas #-}
+
+{-# HLINT ignore "Functor law" #-}
+
 -- |
 -- Module      :  Disco.Desugar
 -- Copyright   :  disco team and contributors
@@ -238,7 +242,7 @@ desugarAbs quant overallTy body = do
   -- Wrap a term in a test frame to report the values of all variables
   -- bound in the patterns.
   addDbgInfo :: [APattern] -> ATerm -> ATerm
-  addDbgInfo ps t = ATTest (map withName $ concatMap varsBound ps) t
+  addDbgInfo ps = ATTest (map withName $ concatMap varsBound ps)
    where
     withName (n, ty) = (name2String n, ty, n)
 
diff --git a/src/Disco/Eval.hs b/src/Disco/Eval.hs
index b5ddd356..6e2a490e 100644
--- a/src/Disco/Eval.hs
+++ b/src/Disco/Eval.hs
@@ -100,7 +100,7 @@ import Disco.Value
 -- Configuation options
 ------------------------------------------------------------
 
-data DiscoConfig = DiscoConfig
+newtype DiscoConfig = DiscoConfig
   { _debugMode :: Bool
   }
 
@@ -185,7 +185,7 @@ inputSettings =
 
 -- | Run a top-level computation.
 runDisco :: DiscoConfig -> (forall r. Members DiscoEffects r => Sem r ()) -> IO ()
-runDisco cfg m =
+runDisco cfg =
   void
     . H.runInputT inputSettings
     . runFinal @(H.InputT IO)
@@ -201,7 +201,6 @@ runDisco cfg m =
     . mapError EvalErr -- Embed runtime errors into top-level error type
     . failToError Panic -- Turn pattern-match failures into a Panic error
     . runReader emptyCtx -- Keep track of current Env
-    $ m
  where
   msgFilter
     | cfg ^. debugMode = const True
diff --git a/src/Disco/Messages.hs b/src/Disco/Messages.hs
index afacd7d1..0e5eab99 100644
--- a/src/Disco/Messages.hs
+++ b/src/Disco/Messages.hs
@@ -1,10 +1,6 @@
 {-# LANGUAGE DeriveFunctor #-}
 {-# LANGUAGE TemplateHaskell #-}
 
------------------------------------------------------------------------------
-
------------------------------------------------------------------------------
-
 -- |
 -- Module      :  Disco.Messages
 -- Copyright   :  disco team and contributors
@@ -30,7 +26,7 @@ data MessageType
   | Debug
   deriving (Show, Read, Eq, Ord, Enum, Bounded)
 
-data Message ann = Message {_messageType :: MessageType, _message :: (Doc ann)}
+data Message ann = Message {_messageType :: MessageType, _message :: Doc ann}
   deriving (Show)
 
 makeLenses ''Message
diff --git a/src/Disco/Parser.hs b/src/Disco/Parser.hs
index 74f07149..fff2abca 100644
--- a/src/Disco/Parser.hs
+++ b/src/Disco/Parser.hs
@@ -1,4 +1,6 @@
 {-# LANGUAGE TemplateHaskell #-}
+{-# OPTIONS_GHC -fno-warn-unrecognised-pragmas #-}
+{-# HLINT ignore "Functor law" #-}
 
 -- |
 -- Module      :  Disco.Parser
@@ -346,7 +348,7 @@ decimal =
     -- either some digits optionally followed by bracketed digits...
     (,) <$> some digit <*> optional (brackets (some digit))
       -- ...or just bracketed digits.
-      <|> ([],) <$> (Just <$> brackets (some digit))
+      <|> (([],) . Just <$> brackets (some digit))
 
   readDecimal a (b, mrep) =
     read a % 1 -- integer part
diff --git a/src/Disco/Subst.hs b/src/Disco/Subst.hs
index 5d11c02a..c8905ac8 100644
--- a/src/Disco/Subst.hs
+++ b/src/Disco/Subst.hs
@@ -1,9 +1,5 @@
 {-# LANGUAGE OverloadedStrings #-}
 
------------------------------------------------------------------------------
-
------------------------------------------------------------------------------
-
 -- SPDX-License-Identifier: BSD-3-Clause
 
 -- |
@@ -98,7 +94,7 @@ x |-> t = Substitution (M.singleton x t)
 --   As one would expect, composition is associative and has 'idS' as
 --   its identity.
 (@@) :: Subst a a => Substitution a -> Substitution a -> Substitution a
-(Substitution s1) @@ (Substitution s2) = Substitution ((M.map (applySubst (Substitution s1))) s2 `M.union` s1)
+(Substitution s1) @@ (Substitution s2) = Substitution $ M.map (applySubst (Substitution s1)) s2 `M.union` s1
 
 -- | Compose a whole container of substitutions.  For example,
 --   @compose [s1, s2, s3] = s1 \@\@ s2 \@\@ s3@.
diff --git a/src/Disco/Typecheck.hs b/src/Disco/Typecheck.hs
index 0ed3df14..ffae5824 100644
--- a/src/Disco/Typecheck.hs
+++ b/src/Disco/Typecheck.hs
@@ -468,7 +468,7 @@ inferTop t = do
       cvs = containerVars (getType at')
 
       -- Replace them all with List.
-      at'' = applySubst (Subst.fromList $ zip (S.toList cvs) (repeat (TyAtom (ABase CtrList)))) at'
+      at'' = applySubst (Subst.fromList $ map (, TyAtom (ABase CtrList)) (S.toList cvs)) at'
 
   -- Finally, quantify over any remaining type variables and return
   -- the term along with the resulting polymorphic type.
@@ -981,7 +981,7 @@ typecheck (Check checkTy) tm@(TAbs Lam body) = do
   -- Then check the type of the body under a context extended with
   -- types for all the arguments.
   extends ctx $
-    ATAbs Lam checkTy <$> (bind (coerce typedArgs) <$> check t resTy)
+    ATAbs Lam checkTy . bind (coerce typedArgs) <$> check t resTy
  where
   -- Given the patterns and their optional type annotations in the
   -- head of a lambda (e.g.  @x (y:Z) (f : N -> N) -> ...@), and the