diff --git a/tower-aadl/src/Tower/AADL.hs b/tower-aadl/src/Tower/AADL.hs
index 3cd31dd..d4bbadd 100644
--- a/tower-aadl/src/Tower/AADL.hs
+++ b/tower-aadl/src/Tower/AADL.hs
@@ -28,7 +28,6 @@ import           Control.Monad hiding (forever)
 import           System.FilePath (addExtension, takeFileName, (<.>))
 import           System.IO (hPutStrLn, stderr)
 import           System.Exit (exitFailure)
-import           MonadLib (runWriterT)
 import           Text.PrettyPrint.Leijen hiding ((</>))
 import qualified Text.PrettyPrint
 
@@ -110,16 +109,19 @@ compileTowerAADLForPlatform fromEnv mkEnv twr' = do
 
   unless (validCIdent appname) $ error $ "appname must be valid c identifier; '"
                                         ++ appname ++ "' is not"
-  (cmodules, errors) <- runWriterT $ O.compileUnits mods copts
+  (ecmodules, errors) <- O.compileUnits mods copts
   hPutStrLn stderr
     . Text.PrettyPrint.render
     $ Text.PrettyPrint.vcat
         errors
 
-  let (appMods, libMods) =
-        partition (\m -> O.unitName m `elem` pkgs) cmodules
-  O.outputCompiler appMods (as osspecific) (osSpecificOptsApps osspecific cfg copts)
-  O.outputCompiler libMods []              (osSpecificOptsLibs osspecific cfg copts)
+  case ecmodules of
+    Left errs -> error $ show errs
+    Right cmodules -> do
+      let (appMods, libMods) =
+            partition (\m -> O.unitName m `elem` pkgs) cmodules
+      O.outputCompiler appMods (as osspecific) (osSpecificOptsApps osspecific cfg copts)
+      O.outputCompiler libMods []              (osSpecificOptsLibs osspecific cfg copts)
   where
 
   -- | AADL assumes that our handlers will always have a callback define. So we
diff --git a/tower-aadl/tower-aadl.cabal b/tower-aadl/tower-aadl.cabal
index 29787e5..a8f5089 100644
--- a/tower-aadl/tower-aadl.cabal
+++ b/tower-aadl/tower-aadl.cabal
@@ -29,7 +29,6 @@ library
                , containers
                , directory
                , filepath
-               , monadLib >= 3.7
                , pretty >= 1.1
                , wl-pprint
                , ivory >= 0.1.0.2
diff --git a/tower-mini/src/Tower/Mini.hs b/tower-mini/src/Tower/Mini.hs
index 8857bd4..00fcc58 100644
--- a/tower-mini/src/Tower/Mini.hs
+++ b/tower-mini/src/Tower/Mini.hs
@@ -243,15 +243,18 @@ compileTowerMini _fromEnv mkEnv comps = do
                             , outHdrDir = Just (f </> name </> "include")
                             , outArtDir = Just (f </> name)
                             }
-    (cmodules, errors) <- runWriterT $ compileUnits mods copts'
+    (ecmodules, errors) <- compileUnits mods copts'
     hPutStrLn stderr $ render $ vcat errors
 
-    let (appMods, libMods) =
-          partition (\m -> unitName m `elem` packages) cmodules
-        libAs = dependencies_artifacts deps
+    case ecmodules of
+      Left errs -> error $ show errs
+      Right cmodules -> do
+        let (appMods, libMods) =
+              partition (\m -> unitName m `elem` packages) cmodules
+            libAs = dependencies_artifacts deps
 
-    outputCompiler appMods libAs copts'
-    outputCompiler libMods []    copts'
+        outputCompiler appMods libAs copts'
+        outputCompiler libMods []    copts'
 
 -- | Build an individual minitower component. This is where much of
 -- the action is, as we finally run the underlying 'Tower' program of