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Diffstat (limited to 'docs/users_guide/using-warnings.rst')
| -rw-r--r-- | docs/users_guide/using-warnings.rst | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/docs/users_guide/using-warnings.rst b/docs/users_guide/using-warnings.rst index c0345fb958..9771837b93 100644 --- a/docs/users_guide/using-warnings.rst +++ b/docs/users_guide/using-warnings.rst @@ -113,6 +113,7 @@ The following flags are simple ways to select standard "packages" of warnings: * :ghc-flag:`-Wunused-packages` * :ghc-flag:`-Wunused-type-patterns` * :ghc-flag:`-Wsafe` + * :ghc-flag:`-Wimplicit-lift` .. ghc-flag:: -Weverything :shortdesc: enable all warnings supported by GHC @@ -856,6 +857,22 @@ of ``-W(no-)*``. f :: forall k (a :: k). Proxy a +.. ghc-flag:: -Wimplicit-lift + :shortdesc: warn about implicit ``lift`` in Template Haskell quotes + :type: dynamic + :reverse: -Wno-implicit-lift + :category: warnings + + :since: 9.2 + + Template Haskell quotes referring to local variables bound outside + of the quote are implicitly converted to use ``lift`. For example, + ``f x = [| reverse x |]`` becomes ``f x = [| reverse $(lift x) |])``. + This flag issues a warning for every such implicit addition of ``lift``. + This can be useful when debugging more complex staged programs, + where an implicit `lift`` can accidentally conceal a variable + used at a wrong stage. + .. ghc-flag:: -Wimplicit-prelude :shortdesc: warn when the Prelude is implicitly imported :type: dynamic |