src, nix: hlint update

This pulls in an updated hlint version from nixpkgs, and fixes some
new eta-reduction warnings. (I don't particularly think this is more
readable, but I suppose being consistently hlint-clean is worth it.)

default.nix

@@ -141,23 +141,7 @@ rec {
 
   # Linting and styling tools.
   style =
-    let
+    pkgs.callPackage nix/tools/style.nix { inherit hsie; };
-      # keep old version of hlint to not deal with linter changes for now
-      nixpkgsVersionPrev = {
-        date = "2021-11-02";
-        rev = "7053541084bf5ce2921ef307e5585d39d7ba8b3f";
-        tarballHash = "1flhh5d4zy43x6060hvzjb5hi5cmc51ivc0nwmija9n8d35kcc4x";
-      };
-
-      nixpkgsPrev =
-        builtins.fetchTarball {
-          url = "https://github.com/nixos/nixpkgs/archive/${nixpkgsVersionPrev.rev}.tar.gz";
-          sha256 = nixpkgsVersionPrev.tarballHash;
-        };
-      pkgsPrev = import nixpkgsPrev { };
-      inherit (pkgsPrev) hlint;
-    in
-    pkgs.callPackage nix/tools/style.nix { inherit hlint hsie; };
 
   # Scripts for running tests.
   tests =

src/PostgREST/Admin.hs

@@ -60,8 +60,8 @@ reachMainApp AppConfig{..} =
               "*6" -> ipv6Addrs xs ++ ipv4Addrs xs
               "!6" -> ipv6Addrs xs
               _    -> xs
-        ipv4Addrs xs = filter ((/=) AF_INET6 . addrFamily) xs
+        ipv4Addrs = filter ((/=) AF_INET6 . addrFamily)
-        ipv6Addrs xs = filter ((==) AF_INET6 . addrFamily) xs
+        ipv6Addrs = filter ((==) AF_INET6 . addrFamily)
 
       addrs <- getAddrInfo (Just $ defaultHints { addrSocketType = Stream }) (T.unpack <$> host) (Just . show $ configServerPort)
       tryAddr `traverse` filterAddrs addrs

src/PostgREST/Config.hs

@@ -175,10 +175,10 @@ class JustIfMaybe a b where
   justIfMaybe :: a -> b
 
 instance JustIfMaybe a a where
-  justIfMaybe a = a
+  justIfMaybe = identity
 
 instance JustIfMaybe a (Maybe a) where
-  justIfMaybe a = Just a
+  justIfMaybe = Just
 
 -- | Reads and parses the config and overrides its parameters from env vars,
 -- files or db settings.

src/PostgREST/Request/ApiRequest.hs

@@ -455,7 +455,7 @@ findProc qi argumentsKeys paramsAsSingleObject allProcs contentType isInvPost =
     matchProc = overloadedProcPartition $ HM.lookupDefault mempty qi allProcs -- first find the proc by name
     -- The partition obtained has the form (overloadedProcs,fallbackProcs)
     -- where fallbackProcs are functions with a single unnamed parameter
-    overloadedProcPartition procs = foldr select ([],[]) procs
+    overloadedProcPartition = foldr select ([],[])
     select proc ~(ts,fs)
       | matchesParams proc         = (proc:ts,fs)
       | hasSingleUnnamedParam proc = (ts,proc:fs)

src/PostgREST/Request/DbRequestBuilder.hs

@@ -359,7 +359,7 @@ callRequest proc apiReq readReq = FunctionCall {
             | ppName prm == mempty -> OnePosParam prm
             | otherwise            -> KeyParams $ specifiedParams [prm]
       prms  -> KeyParams $ specifiedParams prms
-    specifiedParams params = filter (\x -> ppName x `S.member` iColumns apiReq) params
+    specifiedParams = filter (\x -> ppName x `S.member` iColumns apiReq)
 
 returningCols :: ReadRequest -> [FieldName] -> [FieldName]
 returningCols rr@(Node _ forest) pkCols