diff --git a/explicit-exception.cabal b/explicit-exception.cabal
--- a/explicit-exception.cabal
+++ b/explicit-exception.cabal
@@ -1,5 +1,5 @@
 Name:             explicit-exception
-Version:          0.1.9.2
+Version:          0.1.10
 License:          BSD3
 License-File:     LICENSE
 Author:           Henning Thielemann <haskell@henning-thielemann.de>
@@ -41,7 +41,7 @@
 Source-Repository this
   type:     darcs
   location: http://hub.darcs.net/thielema/explicit-exception/
-  tag:      0.1.9.2
+  tag:      0.1.10
 
 Flag buildTests
   description: Build executables that demonstrate some space leaks
diff --git a/src/Control/Monad/Exception/Synchronous.hs b/src/Control/Monad/Exception/Synchronous.hs
--- a/src/Control/Monad/Exception/Synchronous.hs
+++ b/src/Control/Monad/Exception/Synchronous.hs
@@ -67,7 +67,7 @@
    ) where
 
 import Control.Applicative (Applicative(pure, (<*>)))
-import Control.Monad (Monad, return, fail, liftM, liftM2, (>>=), (>>), (=<<),
+import Control.Monad (Monad, return, liftM, liftM2, (>>=), (>>), (=<<),
           {- MonadPlus(mzero, mplus), -})
 import Control.Monad.Fix (MonadFix, mfix, )
 import Control.Monad.Trans.Class (MonadTrans, lift, )
@@ -200,6 +200,10 @@
       Success a   -> a
       Exception e -> handler e
 
+{-
+Semigroup instance could replace (Math.Checksum.IBAN.+++).
+-}
+
 -- like Applicative.<|>
 infixl 3 `alternative`, `alternativeT`
 
@@ -257,7 +261,6 @@
 
 instance Monad (Exceptional e) where
    return = Success
-   fail _msg = Exception (error "Exception.Synchronous: Monad.fail method is not supported")
    x >>= f =
       case x of
          Exception e -> Exception e
diff --git a/src/Control/Monad/Exception/Warning.hs b/src/Control/Monad/Exception/Warning.hs
--- a/src/Control/Monad/Exception/Warning.hs
+++ b/src/Control/Monad/Exception/Warning.hs
@@ -75,10 +75,6 @@
 
 instance Monad (Warnable e) where
    return = Warnable [] -- [Nothing]?
-   fail _msg =
-      Warnable
-         [Just (error "Warning.fail exception")]
-         (error "Warning.fail result")
    x >>= f =
       case x of
          Warnable e0 y ->