Better error message for Context mempty

This commit is contained in:
Jasper Van der Jeugt 2012-11-29 13:47:47 +01:00
parent a8182c9fc9
commit 0e925e71e1

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@ -51,7 +51,7 @@ newtype Context a = Context
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instance Monoid (Context a) where
mempty = Context $ \_ _ -> empty
mempty = missingField
mappend (Context f) (Context g) = Context $ \k i -> f k i <|> g k i