diff options
Diffstat (limited to 'libraries')
| -rw-r--r-- | libraries/base/Data/Foldable.hs | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/libraries/base/Data/Foldable.hs b/libraries/base/Data/Foldable.hs index ce097df581..0a8b00380d 100644 --- a/libraries/base/Data/Foldable.hs +++ b/libraries/base/Data/Foldable.hs @@ -270,6 +270,8 @@ class Foldable t where -- | @since 2.01 instance Foldable Maybe where + foldMap = maybe mempty + foldr _ z Nothing = z foldr f z (Just x) = f x z |