Pushes import suggestions for the Prelude to the back

This way if you just apply import suggestions one by one the Prelude
always remains the last implicit import

src/Main.purs

@@ -2,8 +2,8 @@ module Main where
 
 import Prelude
 
-import Control.Monad.Reader (class MonadAsk, ReaderT, ask, runReaderT)
 import Data.Argonaut (Json)
+import Control.Monad.Reader (class MonadAsk, ReaderT, ask, runReaderT)
 import Data.Array as Array
 import Data.Either (Either(..), either, isRight)
 import Data.Maybe (Maybe(..))

src/Pscid/Psa.purs

@@ -11,6 +11,7 @@ import Data.Argonaut (Json, decodeJson)
 import Data.Array as Array
 import Data.Either (Either, hush)
 import Data.Maybe (Maybe(..), fromMaybe)
+import Data.Maybe as Maybe
 import Data.Set as Set
 import Data.String as String
 import Data.Traversable (traverse)
@@ -19,7 +20,7 @@ import Effect.Console as Console
 import Effect.Exception (catchException)
 import Node.Encoding as Encoding
 import Node.FS.Sync as File
-import Psa (Output, PsaError, PsaOptions, PsaResult, StatVerbosity(..), output, parsePsaError)
+import Psa (Output, PsaError, PsaOptions, PsaResult, StatVerbosity(..), Suggestion, output, parsePsaError)
 import Psa.Printer (renderAnsi, renderRow)
 import Psa.Printer.Default (renderError, renderWarning)
 import Psa.Util (iter_)
@@ -86,6 +87,24 @@ loadLines filename pos = do
   let source = Array.slice (pos.startLine - 1) (pos.endLine) contents
   pure (Just source)
 
+-- | We do this to push imports suggestions for the Prelude to the
+-- | back of the suggestions, so all other modules can be explicitly
+-- | imported first through the suggestions
+reorderWarnings ∷ Array PsaError → Array PsaError
+reorderWarnings errors =
+  let
+    isPreludeImport ∷ Suggestion → Boolean
+    isPreludeImport { replacement } =
+      -- We're checking for two patterns to also catch the case of
+      -- custom preludes that still have Prelude in their name
+      (String.contains (String.Pattern "import")
+       && String.contains (String.Pattern "Prelude")) replacement
+    { yes, no } =
+      Array.partition (Maybe.maybe false isPreludeImport ∘ _.suggestion) errors
+  in no <> yes
+
+-- | Removes warnings that have their error codes ignored and moves
+-- | import suggestions for the Prelude to the back
 filterWarnings ∷ Array String → Array PsaError → Array PsaError
 filterWarnings ignored errors =
-  Array.filter (\e → e.errorCode `Array.notElem` ignored) errors
+  reorderWarnings (Array.filter (\e → e.errorCode `Array.notElem` ignored) errors)