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Diffstat (limited to 'docs/users_guide/using-warnings.rst')
| -rw-r--r-- | docs/users_guide/using-warnings.rst | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/docs/users_guide/using-warnings.rst b/docs/users_guide/using-warnings.rst index 4c2bc88710..deb0e5459d 100644 --- a/docs/users_guide/using-warnings.rst +++ b/docs/users_guide/using-warnings.rst @@ -54,7 +54,8 @@ standard “packages” of warnings: eager to make their code future compatible to adapt to new features before they even generate warnings. - This currently enables only ``-fwarn-missing-monadfail-instance``. + This currently enables ``-fwarn-missing-monadfail-instance`` and + ``-fwarn-semigroup``. ``-Wno-compat`` .. index:: @@ -245,6 +246,21 @@ command line. the `MonadFail Proposal (MFP) <https://prime.haskell.org/wiki/Libraries/Proposals/MonadFail>`__. +``-fwarn-semigroup`` + .. index:: + single: -fwarn-semigroup + single: semigroup + + Warn when definitions are in conflict with the future inclusion of + ``Semigroup`` into the standard typeclasses. + + 1. Instances of ``Monoid`` should also be instances of ``Semigroup`` + 2. The ``Semigroup`` operator ``(<>)`` will be in ``Prelude``, which + clashes with custom local definitions of such an operator + + Being part of the ``-Wcompat`` option group, this warning is off by + default, but will be switched on in a future GHC release. + ``-fwarn-deprecated-flags`` .. index:: single: -fwarn-deprecated-flags |