I have no idea what I am doing

.envrc

@@ -1 +1,2 @@
+nix_direnv_watch_file *.cabal
 use flake

app/Main.hs

@@ -1,4 +1,14 @@
 module Main where
 
+import System.PosixCompat.Types
+import System.PosixCompat.Files
+
+getFileSize :: FilePath -> IO FileOffset
+getFileSize = (fileSize <$>) . getFileStatus
+
+getFolderSize :: FilePath -> IO FileOffset
+getFolderSize path = undefined
+
 main :: IO ()
-main = putStrLn "Hello, Haskell!"
+main = do
+  putStrLn "Hello, Haskell!"

flake.nix

@@ -10,7 +10,7 @@
 
   outputs = { self, nixpkgs, flake-utils }:
     let
-      ghcVer = "ghc962";
+      ghcVer = "ghc945";
       makeHaskellOverlay = overlay: final: prev: {
         haskell = prev.haskell // {
           packages = prev.haskell.packages // {
@@ -52,10 +52,10 @@
               packages = p: [ self.packages.${system}.hcdu ];
               withHoogle = true;
               buildInputs =
-                [ pkgs.docker ] ++
                 (with haskellPackages; [
                   haskell-language-server
                   cabal-install
+                  implicit-hie
                 ]);
               # Change the prompt to show that you are in a devShell
               # shellHook = "export PS1='\\e[1;34mdev > \\e[0m'";

hcdu.cabal

@@ -69,7 +69,9 @@ executable hcdu
         LambdaCase
 
     -- Other library packages from which modules are imported.
-    build-depends:    base ^>=4.18.1.0
+    build-depends:    base ^>=4.17.1.0
+                    , brick >= 1.9
+                    , unix-compat >= 0.7
 
     -- Directories containing source files.
     hs-source-dirs:   app

hie.yaml

@@ -0,0 +1,4 @@
+cradle:
+  cabal:
+    - path: "app/Main.hs"
+      component: "hcdu:exe:hcdu"