diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -4,6 +4,10 @@
 
 ## Released changes
 
+### 0.3.0.3
+
+- fix runtime error on WARN
+
 ### 0.3.0.2
 
 - fix runtime error on PARTIAL_INSTANCE
diff --git a/call-alloy.cabal b/call-alloy.cabal
--- a/call-alloy.cabal
+++ b/call-alloy.cabal
@@ -5,7 +5,7 @@
 -- see: https://github.com/sol/hpack
 
 name:           call-alloy
-version:        0.3.0.2
+version:        0.3.0.3
 synopsis:       A simple library to call Alloy given a specification
 description:    Please see the README on GitHub at <https://github.com/marcellussiegburg/call-alloy#readme>
 category:       Language
diff --git a/src/Language/Alloy/Internal/Call.hs b/src/Language/Alloy/Internal/Call.hs
--- a/src/Language/Alloy/Internal/Call.hs
+++ b/src/Language/Alloy/Internal/Call.hs
@@ -169,6 +169,24 @@
     filterLast _ []     = []
     filterLast p x@[_]  = filter p x
     filterLast p (x:xs) = x:filterLast p xs
+{-
+    prependLine xs = BS.append xs . BS.append "\n"
+    getWholeOutput h inst = do
+      eof <- hIsEOF h
+      if eof
+        then do
+        let inst' = inst ""
+        return $ if BS.null inst'
+          then id
+          else (inst' :)
+      else catch
+        (do
+          l <- BS.hGetLine h
+          if l == begin
+            then (. ((inst . prependLine l $ "") :)) <$> getWholeOutput h id
+            else getWholeOutput h $ inst . prependLine l)
+        (\(_ :: IOException) -> return id)
+-}
     getWholeOutput h = do
       eof <- hIsEOF h
       if eof
@@ -206,6 +224,12 @@
 and
 
 @
+[main] WARN kodkod.engine.config.Reporter - Temporal formula: will be reduced to possibly unsound static version.
+@
+
+and
+
+@
 PARTIAL_INSTANCE
 @
 
@@ -215,6 +239,8 @@
 removeInfoLines (x:xs)
   | Just _ <- BS.stripPrefix "[main] INFO" x
   = removeInfoLines xs
+  | Just _ <- BS.stripPrefix "[main] WARN" x
+  = removeInfoLines xs
   | x == partialInstance
   = removeInfoLines xs
 removeInfoLines xs = xs
@@ -250,6 +276,51 @@
 getClassPath = do
   mclassPath' <- readIORef mclassPath
   maybe readClassPath return mclassPath'
+
+{-
+{-
+data CallAlloyConfig = Config {
+    alloyJarFile   :: FilePath,
+    alloyClassFile :: FilePath,
+    keepFiles      :: Bool
+  }
+-}
+
+jarFileEnv :: String
+jarFileEnv = "ALLOY_JAR_FILE"
+
+callAlloyEnv :: String
+callAlloyEnv = "CALL_ALLOY_CLASS_FILE"
+
+keepFilesEnv :: String
+keepFilesEnv = "KEEP_ALLOY_FILES"
+
+{-|
+Lookup environment variables which are to prefer if present.
+-}
+getEnvironmentInformation :: IO CallAlloyConfig
+getEnvironmentInformation = do
+  alloy     <- lookupEnv jarFileEnv
+  callAlloy <- lookupEnv callAlloyEnv
+  keep      <- lookupEnv keepFilesEnv
+  let mconfig = Config <$> alloy <*> callAlloy <*> pure (isJust keep)
+  case mconfig of
+    Nothing -> do
+      dataDir <- getXdgDirectory XdgData $ appName </> "dataDir"
+    Just c  -> return c
+-}
+{-
+getVersionFile :: IO FilePath
+getVersionFile = do
+  configDir <- getXdgDirectory XdgConfig appName
+  let versionFile = configDir </> "version"
+  exists <- doesFileExist versionFile
+  if exists
+    then do
+    version <- read <$> readFile versionFile
+    unless (version == versionHash) $ createVersionFile configDir versionFile
+    else createVersionFile configDir versionFile
+-}
 
 fallbackToTempDir :: IO FilePath -> IO FilePath
 fallbackToTempDir m = catch m $ \e ->