Implement -Wmissing-kind-signatures

Fixes #19564

7 files changed, 223 insertions, 0 deletions

diff --git a/testsuite/tests/warnings/should_compile/T19564a.hs b/testsuite/tests/warnings/should_compile/T19564a.hs
new file mode 100644
index 0000000000..462d82cc42
--- /dev/null
+++ b/testsuite/tests/warnings/should_compile/T19564a.hs
@@ -0,0 +1,32 @@
+{-# OPTIONS_GHC -Wmissing-kind-signatures #-}
+{-# LANGUAGE GADTs, PolyKinds, TypeFamilies #-}
+-- without standalone kind signatures or cusks: warnings
+module T19564a where
+
+-- type family
+type family Id x where
+    Id Int = Int
+
+-- class definition
+class Functor f => Alt f where
+    (<!>) :: f a -> f a -> f a
+
+-- type alias
+type Arr a b = a -> b
+type B = Bool
+
+-- Haskell98 data
+data YesNo = Yes | No
+data V2 a = V2 a a
+
+-- GADT
+data Free f a where
+    Pure :: a -> Free f a
+    Ap   :: f b -> Free f (b -> a) -> Free f a
+
+-- data family
+data family D1 a
+
+-- associated type family
+class C a where
+    type AT a b
diff --git a/testsuite/tests/warnings/should_compile/T19564a.stderr b/testsuite/tests/warnings/should_compile/T19564a.stderr
new file mode 100644
index 0000000000..f64805fa31
--- /dev/null
+++ b/testsuite/tests/warnings/should_compile/T19564a.stderr
@@ -0,0 +1,36 @@
+
+T19564a.hs:7:1: warning: [-Wmissing-kind-signatures]
+    Top-level type constructor with no standalone kind signature:
+      type Id :: * -> *
+
+T19564a.hs:11:1: warning: [-Wmissing-kind-signatures]
+    Top-level type constructor with no standalone kind signature:
+      type Alt :: (* -> *) -> Constraint
+
+T19564a.hs:15:1: warning: [-Wmissing-kind-signatures]
+    Top-level type constructor with no standalone kind signature:
+      type Arr :: * -> * -> *
+
+T19564a.hs:16:1: warning: [-Wmissing-kind-signatures]
+    Top-level type constructor with no standalone kind signature:
+      type B :: *
+
+T19564a.hs:19:1: warning: [-Wmissing-kind-signatures]
+    Top-level type constructor with no standalone kind signature:
+      type YesNo :: *
+
+T19564a.hs:20:1: warning: [-Wmissing-kind-signatures]
+    Top-level type constructor with no standalone kind signature:
+      type V2 :: * -> *
+
+T19564a.hs:23:1: warning: [-Wmissing-kind-signatures]
+    Top-level type constructor with no standalone kind signature:
+      type Free :: (* -> *) -> * -> *
+
+T19564a.hs:28:1: warning: [-Wmissing-kind-signatures]
+    Top-level type constructor with no standalone kind signature:
+      type D1 :: * -> *
+
+T19564a.hs:31:1: warning: [-Wmissing-kind-signatures]
+    Top-level type constructor with no standalone kind signature:
+      type C :: forall {k}. k -> Constraint
diff --git a/testsuite/tests/warnings/should_compile/T19564b.hs b/testsuite/tests/warnings/should_compile/T19564b.hs
new file mode 100644
index 0000000000..a981e9f61c
--- /dev/null
+++ b/testsuite/tests/warnings/should_compile/T19564b.hs
@@ -0,0 +1,46 @@
+{-# OPTIONS_GHC -Wmissing-kind-signatures #-}
+{-# LANGUAGE GADTs, PolyKinds, TypeFamilies #-}
+-- with kind signatures: no warnings
+module T19564b where
+
+import Data.Kind (Type, Constraint)
+
+-- type family
+type Id :: Type -> Type
+type family Id x where
+    Id Int = Int
+
+-- class definition
+type Alt :: (Type -> Type) -> Constraint
+class Functor f => Alt f where
+    (<!>) :: f a -> f a -> f a
+
+-- type alias
+type Arr :: Type -> Type -> Type
+type Arr a b = a -> b
+
+type B :: Type
+type B = Bool
+
+-- Haskell98 data
+type YesNo :: Type
+data YesNo = Yes | No
+
+type V2 :: Type -> Type
+data V2 a = V2 a a
+
+-- GADT
+type Free :: (Type -> Type) -> (Type -> Type)
+data Free f a where
+    Pure :: a -> Free f a
+    Ap   :: f b -> Free f (b -> a) -> Free f a
+
+-- data family
+type D1 :: Type -> Type
+data family D1 a
+
+-- associated type family
+type C :: Type -> Constraint
+class C a where
+    -- is defaulted, doesn't need annotation
+    type AT a b
diff --git a/testsuite/tests/warnings/should_compile/T19564c.hs b/testsuite/tests/warnings/should_compile/T19564c.hs
new file mode 100644
index 0000000000..6f950b7307
--- /dev/null
+++ b/testsuite/tests/warnings/should_compile/T19564c.hs
@@ -0,0 +1,34 @@
+{-# OPTIONS_GHC -Wmissing-kind-signatures #-}
+{-# LANGUAGE GADTs, PolyKinds, TypeFamilies #-}
+-- with cusks but without -XCUSK, warnings
+module T19564c where
+
+import Data.Kind (Type, Constraint)
+
+-- type family
+type family Id (x :: Type) :: Type where
+    Id Int = Int
+
+-- class definition
+class Functor f => Alt (f :: Type -> Type) where
+    (<!>) :: f a -> f a -> f a
+
+-- type alias
+type Arr (a :: Type) (b :: Type) = a -> b :: Type
+type B = Bool :: Type
+
+-- Haskell98 data
+data YesNo = Yes | No
+data V2 (a :: Type) = V2 a a
+
+-- GADT
+data Free (f :: Type -> Type) (a :: Type) where
+    Pure :: a -> Free f a
+    Ap   :: f b -> Free f (b -> a) -> Free f a
+
+-- data family
+data family D1 (a :: Type)
+
+-- associated type family
+class C (a :: Type) where
+    type AT a b
diff --git a/testsuite/tests/warnings/should_compile/T19564c.stderr b/testsuite/tests/warnings/should_compile/T19564c.stderr
new file mode 100644
index 0000000000..587ea089fc
--- /dev/null
+++ b/testsuite/tests/warnings/should_compile/T19564c.stderr
@@ -0,0 +1,36 @@
+
+T19564c.hs:9:1: warning: [-Wmissing-kind-signatures]
+    Top-level type constructor with no standalone kind signature:
+      type Id :: * -> *
+
+T19564c.hs:13:1: warning: [-Wmissing-kind-signatures]
+    Top-level type constructor with no standalone kind signature:
+      type Alt :: (* -> *) -> Constraint
+
+T19564c.hs:17:1: warning: [-Wmissing-kind-signatures]
+    Top-level type constructor with no standalone kind signature:
+      type Arr :: * -> * -> *
+
+T19564c.hs:18:1: warning: [-Wmissing-kind-signatures]
+    Top-level type constructor with no standalone kind signature:
+      type B :: *
+
+T19564c.hs:21:1: warning: [-Wmissing-kind-signatures]
+    Top-level type constructor with no standalone kind signature:
+      type YesNo :: *
+
+T19564c.hs:22:1: warning: [-Wmissing-kind-signatures]
+    Top-level type constructor with no standalone kind signature:
+      type V2 :: * -> *
+
+T19564c.hs:25:1: warning: [-Wmissing-kind-signatures]
+    Top-level type constructor with no standalone kind signature:
+      type Free :: (* -> *) -> * -> *
+
+T19564c.hs:30:1: warning: [-Wmissing-kind-signatures]
+    Top-level type constructor with no standalone kind signature:
+      type D1 :: * -> *
+
+T19564c.hs:33:1: warning: [-Wmissing-kind-signatures]
+    Top-level type constructor with no standalone kind signature:
+      type C :: * -> Constraint
diff --git a/testsuite/tests/warnings/should_compile/T19564d.hs b/testsuite/tests/warnings/should_compile/T19564d.hs
new file mode 100644
index 0000000000..599f5bbc6a
--- /dev/null
+++ b/testsuite/tests/warnings/should_compile/T19564d.hs
@@ -0,0 +1,34 @@
+{-# OPTIONS_GHC -Wmissing-kind-signatures #-}
+{-# LANGUAGE GADTs, PolyKinds, TypeFamilies, CUSKs #-}
+-- with -XCUSKs, no warnings
+module T19564c where
+
+import Data.Kind (Type, Constraint)
+
+-- type family
+type family Id (x :: Type) :: Type where
+    Id Int = Int
+
+-- class definition
+class Functor f => Alt (f :: Type -> Type) where
+    (<!>) :: f a -> f a -> f a
+
+-- type alias
+type Arr (a :: Type) (b :: Type) = a -> b :: Type
+type B = Bool :: Type
+
+-- Haskell98 data
+data YesNo = Yes | No
+data V2 (a :: Type) = V2 a a
+
+-- GADT
+data Free (f :: Type -> Type) (a :: Type) where
+    Pure :: a -> Free f a
+    Ap   :: f b -> Free f (b -> a) -> Free f a
+
+-- data family
+data family D1 (a :: Type)
+
+-- associated type family
+class C (a :: Type) where
+    type AT a b
diff --git a/testsuite/tests/warnings/should_compile/all.T b/testsuite/tests/warnings/should_compile/all.T
index 7e8668c8d8..f1739aebc3 100644
--- a/testsuite/tests/warnings/should_compile/all.T
+++ b/testsuite/tests/warnings/should_compile/all.T
@@ -38,3 +38,8 @@ test('UnusedPackages', normal, multimod_compile,
     ['UnusedPackages.hs', '-package=bytestring -package=base -package=process -package=ghc -Wunused-packages'])
 
 test('T18402', normal, compile, [''])
+
+test('T19564a', normal, compile, [''])
+test('T19564b', normal, compile, [''])
+test('T19564c', normal, compile, [''])
+test('T19564d', normal, compile, [''])