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

2 files changed, 10 insertions, 1 deletions

diff --git a/testsuite/tests/wcompat-warnings/Template.hs b/testsuite/tests/wcompat-warnings/Template.hs
index e3423c8b9f..03f9a4957e 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 5c2d9c5428..3c3e73ddf6 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.