Better -ddump-types

The debug flag -ddump-types is supposed to show the type
of Ids, and the kinds of type constructors.  It was doing
the former but not the latter -- instead it was using
showTyTying, which is actually less helpful when debugging.

This patch changes it to print the kind and roles of the thing.

I also made -ddump-types show pattern synonyms

6 files changed, 28 insertions, 41 deletions

diff --git a/testsuite/tests/roles/should_compile/Roles1.stderr b/testsuite/tests/roles/should_compile/Roles1.stderr
index 4eae0a4754..e11b454f99 100644
--- a/testsuite/tests/roles/should_compile/Roles1.stderr
+++ b/testsuite/tests/roles/should_compile/Roles1.stderr
@@ -8,17 +8,17 @@ TYPE SIGNATURES
   Roles1.K7 :: forall {k} (a :: k) b. b -> T7 a b
 TYPE CONSTRUCTORS
   type role T1 nominal
-  data T1 a = K1 a
-  data T2 a = K2 a
-  type role T3 phantom
-  data T3 (a :: k) = K3
+  T1 :: * -> *
+  T2 :: * -> *
+  type role T3 nominal phantom
+  T3 :: forall k. k -> *
   type role T4 nominal nominal
-  data T4 (a :: * -> *) b = K4 (a b)
-  data T5 a = K5 a
-  type role T6 phantom
-  data T6 (a :: k) = K6
-  type role T7 phantom representational
-  data T7 (a :: k) b = K7 b
+  T4 :: (* -> *) -> * -> *
+  T5 :: * -> *
+  type role T6 nominal phantom
+  T6 :: forall {k}. k -> *
+  type role T7 nominal phantom representational
+  T7 :: forall {k}. k -> * -> *
 COERCION AXIOMS
 Dependent modules: []
 Dependent packages: [base-4.12.0.0, ghc-prim-0.5.3,
diff --git a/testsuite/tests/roles/should_compile/Roles14.stderr b/testsuite/tests/roles/should_compile/Roles14.stderr
index 86434f1ed1..57899142d9 100644
--- a/testsuite/tests/roles/should_compile/Roles14.stderr
+++ b/testsuite/tests/roles/should_compile/Roles14.stderr
@@ -2,9 +2,7 @@ TYPE SIGNATURES
   meth2 :: forall a. C2 a => a -> a
 TYPE CONSTRUCTORS
   type role C2 representational
-  class C2 a where
-    meth2 :: a -> a
-    {-# MINIMAL meth2 #-}
+  C2 :: * -> Constraint
 COERCION AXIOMS
   axiom Roles12.N:C2 :: C2 a = a -> a -- Defined at Roles14.hs:6:1
 Dependent modules: []
diff --git a/testsuite/tests/roles/should_compile/Roles2.stderr b/testsuite/tests/roles/should_compile/Roles2.stderr
index 244b32feb7..81cf221fbd 100644
--- a/testsuite/tests/roles/should_compile/Roles2.stderr
+++ b/testsuite/tests/roles/should_compile/Roles2.stderr
@@ -2,9 +2,9 @@ TYPE SIGNATURES
   Roles2.K1 :: forall a. IO a -> T1 a
   Roles2.K2 :: forall a. FunPtr a -> T2 a
 TYPE CONSTRUCTORS
-  data T1 a = K1 (IO a)
+  T1 :: * -> *
   type role T2 phantom
-  data T2 a = K2 (FunPtr a)
+  T2 :: * -> *
 COERCION AXIOMS
 Dependent modules: []
 Dependent packages: [base-4.12.0.0, ghc-prim-0.5.3,
diff --git a/testsuite/tests/roles/should_compile/Roles3.stderr b/testsuite/tests/roles/should_compile/Roles3.stderr
index aa2a07f459..ff36be8bdf 100644
--- a/testsuite/tests/roles/should_compile/Roles3.stderr
+++ b/testsuite/tests/roles/should_compile/Roles3.stderr
@@ -4,22 +4,15 @@ TYPE SIGNATURES
   meth3 :: forall a b. C3 a b => a -> F3 b -> F3 b
   meth4 :: forall a b. C4 a b => a -> F4 b -> F4 b
 TYPE CONSTRUCTORS
-  class C1 a where
-    meth1 :: a -> a
-    {-# MINIMAL meth1 #-}
-  class C2 a b where
-    meth2 :: (a ~ b) => a -> b
-    {-# MINIMAL meth2 #-}
-  class C3 a b where
-    type family F3 b :: * open
-    meth3 :: a -> F3 b -> F3 b
-    {-# MINIMAL meth3 #-}
-  class C4 a b where
-    meth4 :: a -> F4 b -> F4 b
-    {-# MINIMAL meth4 #-}
-  type family F4 a :: * open
-  type Syn1 a = F4 a
-  type Syn2 a = [a]
+  C1 :: * -> Constraint
+  C2 :: * -> * -> Constraint
+  C3 :: * -> * -> Constraint
+  C4 :: * -> * -> Constraint
+  type role F4 nominal
+  F4 :: * -> *
+  type role Syn1 nominal
+  Syn1 :: * -> *
+  Syn2 :: * -> *
 COERCION AXIOMS
   axiom Roles3.N:C1 :: C1 a = a -> a -- Defined at Roles3.hs:6:1
   axiom Roles3.N:C2 ::
diff --git a/testsuite/tests/roles/should_compile/Roles4.stderr b/testsuite/tests/roles/should_compile/Roles4.stderr
index 9f8803d11d..93a86a514c 100644
--- a/testsuite/tests/roles/should_compile/Roles4.stderr
+++ b/testsuite/tests/roles/should_compile/Roles4.stderr
@@ -2,13 +2,9 @@ TYPE SIGNATURES
   meth1 :: forall a. C1 a => a -> a
   meth3 :: forall a. C3 a => a -> Syn1 a
 TYPE CONSTRUCTORS
-  class C1 a where
-    meth1 :: a -> a
-    {-# MINIMAL meth1 #-}
-  class C3 a where
-    meth3 :: a -> Syn1 a
-    {-# MINIMAL meth3 #-}
-  type Syn1 a = [a]
+  C1 :: * -> Constraint
+  C3 :: * -> Constraint
+  Syn1 :: * -> *
 COERCION AXIOMS
   axiom Roles4.N:C1 :: C1 a = a -> a -- Defined at Roles4.hs:6:1
   axiom Roles4.N:C3 ::
diff --git a/testsuite/tests/roles/should_compile/T8958.stderr b/testsuite/tests/roles/should_compile/T8958.stderr
index db4e8330de..55a6303b64 100644
--- a/testsuite/tests/roles/should_compile/T8958.stderr
+++ b/testsuite/tests/roles/should_compile/T8958.stderr
@@ -5,10 +5,10 @@ TYPE SIGNATURES
   T8958.MkMap :: forall k v. [(k, v)] -> Map k v
 TYPE CONSTRUCTORS
   type role Map nominal representational
-  newtype (Nominal k, Representational v) => Map k v = MkMap [(k, v)]
-  class Nominal a
+  Map :: * -> * -> *
+  Nominal :: * -> Constraint
   type role Representational representational
-  class Representational a
+  Representational :: * -> Constraint
 COERCION AXIOMS
   axiom T8958.N:Map :: Map k v = [(k, v)] -- Defined at T8958.hs:13:1
 INSTANCES