diff options
Diffstat (limited to 'docs/users_guide/using-warnings.rst')
| -rw-r--r-- | docs/users_guide/using-warnings.rst | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/docs/users_guide/using-warnings.rst b/docs/users_guide/using-warnings.rst index dda7bb656c..31060d701d 100644 --- a/docs/users_guide/using-warnings.rst +++ b/docs/users_guide/using-warnings.rst @@ -26,6 +26,7 @@ generally likely to indicate bugs in your program. These are: * :ghc-flag:`-Wdeprecated-flags` * :ghc-flag:`-Wunrecognised-pragmas` * :ghc-flag:`-Wduplicate-exports` + * :ghc-flag:`-Wderiving-defaults` * :ghc-flag:`-Woverflowed-literals` * :ghc-flag:`-Wempty-enumerations` * :ghc-flag:`-Wmissing-fields` @@ -640,6 +641,23 @@ of ``-W(no-)*``. Causes a warning to be emitted if an enumeration is empty, e.g. ``[5 .. 3]``. +.. ghc-flag:: -Wderiving-defaults + :shortdesc: warn about default deriving when using both + DeriveAnyClass and GeneralizedNewtypeDeriving + :type: dynamic + :reverse: -Wno-deriving-defaults + :category: + + :since: 8.10 + + Causes a warning when both :ref:`DeriveAnyClass` and + :ref:`GeneralizedNewtypeDeriving` are enabled and no explicit + deriving strategy is in use. For example, this would result a + warning: :: + + class C a + newtype T a = MkT a deriving C + .. ghc-flag:: -Wduplicate-constraints :shortdesc: warn when a constraint appears duplicated in a type signature :type: dynamic |