Distinguish between userError (i.e., deliberate failure) and other immediate and...

diff --git a/compiler/typecheck/TcSplice.lhs b/compiler/typecheck/TcSplice.lhs
index b675cf9..c7dccc4 100644 (file)
--- a/compiler/typecheck/TcSplice.lhs
+++ b/compiler/typecheck/TcSplice.lhs
@@ -394,17 +394,17 @@ runMeta convert expr
                -- exception-cacthing thing so that if there are any lurking 
                -- exceptions in the data structure returned by hval, we'll
                -- encounter them inside the try
-         either_tval <- tryAllM $ do
-               { th_syn <- TH.runQ (unsafeCoerce# hval)
-               ; case convert (getLoc expr) th_syn of
-                   Left err     -> do { addErrTc err; return Nothing }
-                   Right hs_syn -> return (Just hs_syn) }
-
-       ; case either_tval of
-             Right (Just v) -> return v
-             Right Nothing  -> failM   -- Error already in Tc monad
-             Left exn       -> failWithTc (mk_msg "run" exn)   -- Exception
-       }}}
+          either_th_syn <- tryAllM $ tryM $ TH.runQ $ unsafeCoerce# hval
+        ; case either_th_syn of
+            Left exn             -> failWithTc (mk_msg "run" exn)
+            Right (Left exn)     -> failM  -- Error already in Tc monad
+            Right (Right th_syn) -> do
+        { either_hs_syn <- tryAllM $ return $! convert (getLoc expr) th_syn
+        ; case either_hs_syn of
+            Left exn             -> failWithTc (mk_msg "interpret result of" exn)
+            Right (Left err)     -> do { addErrTc err; failM }
+            Right (Right hs_syn) -> return hs_syn
+        }}}}
   where
     mk_msg s exn = vcat [text "Exception when trying to" <+> text s <+> text "compile-time code:",
                         nest 2 (text (Panic.showException exn)),