From 5c420970c162fdee432866a13861e3fa13176a90 Mon Sep 17 00:00:00 2001
From: Edsko de Vries <edsko@well-typed.com>
Date: Tue, 21 Mar 2023 13:14:22 +0100
Subject: [PATCH] Introduce `throwFailure`

---
 src/Foreign/Rust/Failure.hs | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/src/Foreign/Rust/Failure.hs b/src/Foreign/Rust/Failure.hs
index 3043442..1b81cf6 100644
--- a/src/Foreign/Rust/Failure.hs
+++ b/src/Foreign/Rust/Failure.hs
@@ -2,10 +2,13 @@ module Foreign.Rust.Failure (
     Failure -- Opaque
   , failureMessage
   , mkFailure
+  , throwFailure
+  , throwFailureIO
   ) where
 
-import GHC.Stack
+import Control.Exception
 import Data.Text (Text)
+import GHC.Stack
 
 -- | Failure reported by a Rust function
 --
@@ -14,7 +17,8 @@ data Failure = Failure {
       failureMessage :: Text
     , failureCallstackHaskell :: PrettyCallStack
     }
-  deriving (Show)
+  deriving stock (Show)
+  deriving anyclass (Exception)
 
 mkFailure :: HasCallStack => Text -> Failure
 mkFailure e = Failure e (PrettyCallStack callStack)
@@ -24,4 +28,10 @@ newtype PrettyCallStack = PrettyCallStack CallStack
 instance Show PrettyCallStack where
   show (PrettyCallStack stack) = prettyCallStack stack
 
+throwFailure :: Either Failure a -> a
+throwFailure (Left err) = throw err
+throwFailure (Right a)  = a
 
+throwFailureIO :: Either Failure a -> IO a
+throwFailureIO (Left err) = throwIO err
+throwFailureIO (Right a)  = return a
\ No newline at end of file