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Diffstat (limited to 'docs/users_guide/using-warnings.rst')
| -rw-r--r-- | docs/users_guide/using-warnings.rst | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/docs/users_guide/using-warnings.rst b/docs/users_guide/using-warnings.rst index d93064b464..dba30dbf1e 100644 --- a/docs/users_guide/using-warnings.rst +++ b/docs/users_guide/using-warnings.rst @@ -37,6 +37,7 @@ generally likely to indicate bugs in your program. These are: * :ghc-flag:`-Wtabs` * :ghc-flag:`-Wunrecognised-warning-flags` * :ghc-flag:`-Winaccessible-code` + * :ghc-flag:`-Wstar-is-type` * :ghc-flag:`-Wstar-binder` The following flags are simple ways to select standard "packages" of warnings: @@ -1175,6 +1176,24 @@ of ``-W(no-)*``. since we're passing ``Foo1`` and ``Foo2`` here, it follows that ``t ~ Char``, and ``u ~ Int``, and thus ``t ~ u`` cannot hold. +.. ghc-flag:: -Wstar-is-type + :shortdesc: warn when ``*`` is used to mean ``Data.Kind.Type`` + :type: dynamic + :reverse: -Wno-star-is-type + :category: + + :since: 8.6 + + The use of ``*`` to denote the kind of inhabited types relies on the + :extension:`StarIsType` extension, which in a future release will be + turned off by default and then possibly removed. The reasons for this and + the deprecation schedule are described in `GHC proposal #30 + <https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0030-remove-star-kind.rst>`__. + + This warning allows to detect such uses of ``*`` before the actual + breaking change takes place. The recommended fix is to replace ``*`` with + ``Type`` imported from ``Data.Kind``. + .. ghc-flag:: -Wstar-binder :shortdesc: warn about binding the ``(*)`` type operator despite :ghc-flag:`-XStarIsType` |