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| author | Ben Gamari <ben@smart-cactus.org> | 2019-12-29 15:16:24 -0500 |
|---|---|---|
| committer | Marge Bot <ben+marge-bot@smart-cactus.org> | 2020-02-08 10:17:55 -0500 |
| commit | 4435a8e0b74337fe5faddb9c46691f0f5bf9e653 (patch) | |
| tree | 1d8ac7f540770c017f5e26f51d2788666203fbed /docs | |
| parent | aede171a59f9b7b8022548c385a1cb8c4589f905 (diff) | |
| download | haskell-4435a8e0b74337fe5faddb9c46691f0f5bf9e653.tar.gz | |
Introduce -Wcompat-unqualified-imports
This implements the warning proposed in option (B) of the
Data.List.singleton CLC [discussion][].
This warning, which is included in `-Wcompat` is intended to help users
identify imports of modules that will change incompatibly in future GHC
releases. This currently only includes `Data.List` due to the expected
specialisation and addition of `Data.List.singleton`.
Fixes #17244.
[discussion]: https://groups.google.com/d/msg/haskell-core-libraries/q3zHLmzBa5E/PmlAs_kYAQAJ
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/users_guide/using-warnings.rst | 25 |
1 files changed, 22 insertions, 3 deletions
diff --git a/docs/users_guide/using-warnings.rst b/docs/users_guide/using-warnings.rst index 586af57136..aab74d36c2 100644 --- a/docs/users_guide/using-warnings.rst +++ b/docs/users_guide/using-warnings.rst @@ -124,6 +124,7 @@ The following flags are simple ways to select standard "packages" of warnings: * :ghc-flag:`-Wsemigroup` * :ghc-flag:`-Wnoncanonical-monoid-instances` * :ghc-flag:`-Wstar-is-type` + * :ghc-flag:`-Wcompat-unqualified-imports` .. ghc-flag:: -Wno-compat :shortdesc: Disables all warnings enabled by :ghc-flag:`-Wcompat`. @@ -219,12 +220,31 @@ of ``-W(no-)*``. encountered on the command line. :type: dynamic :reverse: -Wno-unrecognised-warning-flags + :default: on :category: Enables warnings when the compiler encounters a ``-W...`` flag that is not recognised. - This warning is on by default. +.. ghc-flag:: -Wcompat-unqualified-imports + :shortdesc: Report unqualified imports of core libraries which are expected + to cause compatibility problems in future releases. + :type: dynamic + :reverse: -Wno-compat-unqualified-imports + :category: + + Warns on qualified imports of core library modules which are subject to + change in future GHC releases. Currently the following modules are covered + by this warning: + + - ``Data.List`` due to the future addition of ``Data.List.singleton`` and + specialisation of exports to the ``[]`` type. See the + :ref:`mailing list + <https://groups.google.com/forum/#!topic/haskell-core-libraries/q3zHLmzBa5E>` + for details. + + This warning can be addressed by either adding an explicit import list or + using a ``qualified`` import. .. ghc-flag:: -Wtyped-holes :shortdesc: Report warnings when :ref:`typed hole <typed-holes>` errors are @@ -232,14 +252,13 @@ of ``-W(no-)*``. :ghc-flag:`-fdefer-typed-holes`. :type: dynamic :reverse: -Wno-typed-holes + :default: on :category: Determines whether the compiler reports typed holes warnings. Has no effect unless typed holes errors are deferred until runtime. See :ref:`typed-holes` and :ref:`defer-type-errors` - This warning is on by default. - .. ghc-flag:: -Wdeferred-type-errors :shortdesc: Report warnings when :ref:`deferred type errors <defer-type-errors>` are enabled. This option is enabled by |