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Diffstat (limited to 'docs/users_guide/exts/explicit_forall.rst')
| -rw-r--r-- | docs/users_guide/exts/explicit_forall.rst | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/docs/users_guide/exts/explicit_forall.rst b/docs/users_guide/exts/explicit_forall.rst index 8287e510dc..bbd146d6b4 100644 --- a/docs/users_guide/exts/explicit_forall.rst +++ b/docs/users_guide/exts/explicit_forall.rst @@ -37,6 +37,11 @@ Notes: instance forall a. Eq a => Eq [a] where ... + Note that the use of ``forall``s in instance declarations is somewhat + restricted in comparison to other types. For example, instance declarations + are not allowed to contain nested ``forall``s. See + :ref:`formal-instance-syntax` for more information. + - If the :ghc-flag:`-Wunused-foralls` flag is enabled, a warning will be emitted when you write a type variable in an explicit ``forall`` statement that is otherwise unused. For instance: :: |