Apply suggestions from code review

Co-authored-by: Vlad <cstmlcodes@gmail.com>

Author: bladyjoker

lambda-buffers-frontend/resources/run.sh

@@ -1,3 +1,4 @@
+#!/bin/sh
 function lbf {
    cabal run lbf -- $@
 }

lambda-buffers-frontend/src/LambdaBuffers/Frontend.hs

@@ -77,11 +77,10 @@ type FrontendT m a = MonadIO m => ReaderT FrontRead (StateT FrontState (ExceptT
 -- | Run a Frontend compilation action on a "lbf" file, return the entire compilation closure or a frontend error.
 runFrontend :: MonadIO m => [FilePath] -> FilePath -> m (Either FrontendError FrontendResult)
 runFrontend importPaths modFp = do
-  let stM = runReaderT (processFile modFp) (FrontRead (ModuleName [] (SourceInfo "" (SourcePos 0 0) (SourcePos 0 0))) [] importPaths)
+  let stM = runReaderT (processFile modFp) (FrontRead (ModuleName [] defaultSouceInfo)) [] importPaths)
       exM = runStateT stM (FrontState mempty)
       ioM = runExceptT exM
-  _ <- ioM
-  fmap (FrontendResult . importedModules . snd) <$> ioM
+  fmap (FrontendResult . importedModules . snd) <$> runExceptT exM
 
 throwE' :: FrontendError -> FrontendT m a
 throwE' = lift . lift . throwE