[commit: ghc] master: Include -fwarn-star-is-type in -Wcompat (5b2388b)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/5b2388b2cb657771c3c578eaf552b300b79f8260/ghc

>---------------------------------------------------------------

commit 5b2388b2cb657771c3c578eaf552b300b79f8260
Author: Vladislav Zavialov <vlad.z.4096 at gmail.com>
Date:   Fri Oct 12 11:15:26 2018 -0400

    Include -fwarn-star-is-type in -Wcompat
    
    According to the deprecation schedule in the accepted proposal,
    the first step is to include `-fwarn-star-is-type` in `-Wcompat`.
    
    Test Plan: Validate
    
    Reviewers: bgamari
    
    Reviewed By: bgamari
    
    Subscribers: rwbarton, carter
    
    GHC Trac Issues: #15476
    
    Differential Revision: https://phabricator.haskell.org/D5044


>---------------------------------------------------------------

5b2388b2cb657771c3c578eaf552b300b79f8260
 compiler/main/DynFlags.hs                                 | 1 +
 compiler/parser/RdrHsSyn.hs                               | 3 ++-
 docs/users_guide/8.8.1-notes.rst                          | 2 ++
 docs/users_guide/using-warnings.rst                       | 4 ++++
 testsuite/tests/wcompat-warnings/Template.hs              | 5 ++++-
 testsuite/tests/wcompat-warnings/WCompatWarningsOn.stderr | 6 ++++++
 6 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/compiler/main/DynFlags.hs b/compiler/main/DynFlags.hs
index f9ccc25..2c8f134 100644
--- a/compiler/main/DynFlags.hs
+++ b/compiler/main/DynFlags.hs
@@ -4614,6 +4614,7 @@ minusWcompatOpts
       , Opt_WarnSemigroup
       , Opt_WarnNonCanonicalMonoidInstances
       , Opt_WarnImplicitKindVars
+      , Opt_WarnStarIsType
       ]
 
 enableUnusedBinds :: DynP ()
diff --git a/compiler/parser/RdrHsSyn.hs b/compiler/parser/RdrHsSyn.hs
index 1015319..1e89d5a 100644
--- a/compiler/parser/RdrHsSyn.hs
+++ b/compiler/parser/RdrHsSyn.hs
@@ -2049,7 +2049,8 @@ warnStarIsType span = addWarning Opt_WarnStarIsType span msg
     msg =  text "Using" <+> quotes (text "*")
            <+> text "(or its Unicode variant) to mean"
            <+> quotes (text "Data.Kind.Type")
-        $$ text "relies on the StarIsType extension."
+        $$ text "relies on the StarIsType extension, which will become"
+        $$ text "deprecated in the future."
         $$ text "Suggested fix: use" <+> quotes (text "Type")
            <+> text "from" <+> quotes (text "Data.Kind") <+> text "instead."
 
diff --git a/docs/users_guide/8.8.1-notes.rst b/docs/users_guide/8.8.1-notes.rst
index a27aee7..d3da37e 100644
--- a/docs/users_guide/8.8.1-notes.rst
+++ b/docs/users_guide/8.8.1-notes.rst
@@ -59,6 +59,8 @@ Compiler
 
 - New :ghc-flag:`-keep-hscpp-files` to keep the output of the CPP pre-processor.
 
+- The :ghc-flag:`-Wcompat` warning group now includes :ghc-flag:`-Wstar-is-type`.
+
 Runtime system
 ~~~~~~~~~~~~~~
 
diff --git a/docs/users_guide/using-warnings.rst b/docs/users_guide/using-warnings.rst
index dba30db..aeabbe9 100644
--- a/docs/users_guide/using-warnings.rst
+++ b/docs/users_guide/using-warnings.rst
@@ -117,6 +117,7 @@ The following flags are simple ways to select standard "packages" of warnings:
         * :ghc-flag:`-Wsemigroup`
         * :ghc-flag:`-Wnoncanonical-monoid-instances`
         * :ghc-flag:`-Wimplicit-kind-vars`
+        * :ghc-flag:`-Wstar-is-type`
 
 .. ghc-flag:: -Wno-compat
     :shortdesc: Disables all warnings enabled by :ghc-flag:`-Wcompat`.
@@ -1194,6 +1195,9 @@ of ``-W(no-)*``.
      breaking change takes place. The recommended fix is to replace ``*`` with
      ``Type`` imported from ``Data.Kind``.
 
+     Being part of the :ghc-flag:`-Wcompat` option group, this warning is off by
+     default, but will be switched on in a future GHC release.
+
 .. ghc-flag:: -Wstar-binder
      :shortdesc: warn about binding the ``(*)`` type operator despite
          :ghc-flag:`-XStarIsType`
diff --git a/testsuite/tests/wcompat-warnings/Template.hs b/testsuite/tests/wcompat-warnings/Template.hs
index e3423c8..03f9a49 100644
--- a/testsuite/tests/wcompat-warnings/Template.hs
+++ b/testsuite/tests/wcompat-warnings/Template.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE NoMonadFailDesugaring #-}
+{-# LANGUAGE NoMonadFailDesugaring, KindSignatures #-}
 
 module WCompatWarningsOnOff where
 
@@ -21,3 +21,6 @@ instance Monoid S where
   S a `mappend` S b = S (a+b)
   mempty = S 0
 
+-- -fwarn-star-is-type
+b :: (Bool :: *)
+b = True
diff --git a/testsuite/tests/wcompat-warnings/WCompatWarningsOn.stderr b/testsuite/tests/wcompat-warnings/WCompatWarningsOn.stderr
index 5c2d9c5..3c3e73d 100644
--- a/testsuite/tests/wcompat-warnings/WCompatWarningsOn.stderr
+++ b/testsuite/tests/wcompat-warnings/WCompatWarningsOn.stderr
@@ -33,3 +33,9 @@ Template.hs:21:3: warning: [-Wnoncanonical-monoid-instances (in -Wcompat)]
     Noncanonical ‘mappend’ definition detected
     in the instance declaration for ‘Monoid S’.
     Define as ‘mappend = (<>)’
+
+Template.hs:25:15: warning: [-Wstar-is-type (in -Wcompat)]
+    Using ‘*’ (or its Unicode variant) to mean ‘Data.Kind.Type’
+    relies on the StarIsType extension, which will become
+    deprecated in the future.
+    Suggested fix: use ‘Type’ from ‘Data.Kind’ instead.