Compatibility with more plan.json files

1 files changed, 4 insertions, 2 deletions

diff --git a/Main.hs b/Main.hs
index 5cbf592..c1f5f9b 100644
--- a/Main.hs
+++ b/Main.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE LambdaCase #-}
 module Main where
 
 import Control.Monad (forM_, when)
@@ -35,8 +36,9 @@ compatibleTargets pd plan =
 parseCabalPlan' :: FoundCabalSpec -> IO CabalPlan
 parseCabalPlan' foundSpec = 
     parseCabalPlan (foundcsRootDir foundSpec </> "dist-newstyle/cache/plan.json")
-        >>= maybe (die "Cabal plan.json not found; make sure to run 'cabal build' beforehand")
-                  return
+        >>= \case NotFound -> die "Cabal plan.json not found; make sure to run 'cabal build' beforehand"
+                  ParseError e -> die ("Error when parsing Cabal plan.json: " ++ e)
+                  Parsed plan -> return plan
 
 readCachedTargets :: (AnyTarget -> Bool) -> IO (FilePath, [AnyTarget], [(String, [AnyTarget])])
 readCachedTargets predicate = do