Kill Type pretty-printer

Here we consolidate the pretty-printing logic for types in IfaceType. We
need IfaceType regardless and the printer for Type can be implemented in
terms of that for IfaceType. See #11660.

Note that this is very much a work-in-progress. Namely I still have yet
to ponder how to ease the hs-boot file situation, still need to rip out
more dead code, need to move some of the special cases for, e.g., `*` to
the IfaceType printer, and need to get it to validate. That being said,
it comes close to validating as-is.

Test Plan: Validate

Reviewers: goldfire, austin

Subscribers: goldfire, thomie, simonpj

Differential Revision: https://phabricator.haskell.org/D2528

GHC Trac Issues: #11660

16 files changed, 42 insertions, 43 deletions

diff --git a/testsuite/tests/deSugar/should_compile/T2431.stderr b/testsuite/tests/deSugar/should_compile/T2431.stderr
index 43ffb06033..ff1047db84 100644
--- a/testsuite/tests/deSugar/should_compile/T2431.stderr
+++ b/testsuite/tests/deSugar/should_compile/T2431.stderr
@@ -17,7 +17,7 @@ T2431.$WRefl =
     T2431.Refl @ a @ a @~ (<a>_N :: (a :: *) GHC.Prim.~# (a :: *))
 
 -- RHS size: {terms: 4, types: 8, coercions: 0}
-absurd :: forall a. Int :~: Bool -> a
+absurd :: forall a. (Int :~: Bool) -> a
 [GblId, Arity=1, Caf=NoCafRefs, Str=<L,U>x]
 absurd = \ (@ a) (x :: Int :~: Bool) -> case x of { }
 
diff --git a/testsuite/tests/dependent/should_fail/TypeSkolEscape.stderr b/testsuite/tests/dependent/should_fail/TypeSkolEscape.stderr
index 963dcbb6a3..88539858cf 100644
--- a/testsuite/tests/dependent/should_fail/TypeSkolEscape.stderr
+++ b/testsuite/tests/dependent/should_fail/TypeSkolEscape.stderr
@@ -2,6 +2,6 @@
 TypeSkolEscape.hs:8:1: error:
     • Quantified type's kind mentions quantified type variable
       (skolem escape)
-           type: forall a1. a1
+           type: forall (a1 :: TYPE v1). a1
         of kind: TYPE v
     • In the type synonym declaration for ‘Bad’
diff --git a/testsuite/tests/ghci/scripts/T11252.stdout b/testsuite/tests/ghci/scripts/T11252.stdout
index eddba4530e..f6d45ddf32 100644
--- a/testsuite/tests/ghci/scripts/T11252.stdout
+++ b/testsuite/tests/ghci/scripts/T11252.stdout
@@ -1 +1 @@
-Proxy1 :: forall k -> k -> *
+Proxy1 :: k -> *
diff --git a/testsuite/tests/ghci/scripts/T2766.stdout b/testsuite/tests/ghci/scripts/T2766.stdout
index 5bcbd9e75e..f8ee42ff6a 100644
--- a/testsuite/tests/ghci/scripts/T2766.stdout
+++ b/testsuite/tests/ghci/scripts/T2766.stdout
@@ -1,3 +1,3 @@
 first :: Arrow to => b `to` c -> (b, d) `to` (c, d)
   :: Arrow to => to b c -> to (b, d) (c, d)
-first :: b~>c -> (b, d)~>(c, d) :: b ~> c -> (b, d) ~> (c, d)
+first :: b~>c -> (b, d)~>(c, d) :: (b ~> c) -> (b, d) ~> (c, d)
diff --git a/testsuite/tests/ghci/scripts/ghci059.stdout b/testsuite/tests/ghci/scripts/ghci059.stdout
index 3cb103c9f5..9f4e65b344 100644
--- a/testsuite/tests/ghci/scripts/ghci059.stdout
+++ b/testsuite/tests/ghci/scripts/ghci059.stdout
@@ -1,4 +1,4 @@
 type role Coercible representational representational
-class a ~R# b => Coercible (a :: k0) (b :: k0)
+class Coercible a b => Coercible (a :: k0) (b :: k0)
   	-- Defined in ‘GHC.Types’
 coerce :: Coercible a b => a -> b 	-- Defined in ‘GHC.Prim’
diff --git a/testsuite/tests/roles/should_compile/T8958.stderr b/testsuite/tests/roles/should_compile/T8958.stderr
index df20e67f3a..5369daa5cd 100644
--- a/testsuite/tests/roles/should_compile/T8958.stderr
+++ b/testsuite/tests/roles/should_compile/T8958.stderr
@@ -65,8 +65,7 @@ AbsBinds [a] []
    Exported types: T8958.$fRepresentationala [InlPrag=[ALWAYS] CONLIKE]
                      :: forall a. Representational a
                    [LclIdX[DFunId],
-                    Unf=DFun: \ (@ a[ssk:2]) ->
-                          T8958.C:Representational TYPE: a[ssk:2]]
+                    Unf=DFun: \ (@ a) -> T8958.C:Representational TYPE: a]
    Binds: $dRepresentational = T8958.C:Representational @ a
    Evidence: [EvBinds{}]}
 AbsBinds [a] []
@@ -74,8 +73,7 @@ AbsBinds [a] []
                wrap: <>]
    Exported types: T8958.$fNominala [InlPrag=[ALWAYS] CONLIKE]
                      :: forall a. Nominal a
-                   [LclIdX[DFunId],
-                    Unf=DFun: \ (@ a[ssk:2]) -> T8958.C:Nominal TYPE: a[ssk:2]]
+                   [LclIdX[DFunId], Unf=DFun: \ (@ a) -> T8958.C:Nominal TYPE: a]
    Binds: $dNominal = T8958.C:Nominal @ a
    Evidence: [EvBinds{}]}
 
diff --git a/testsuite/tests/typecheck/should_compile/T10632.stderr b/testsuite/tests/typecheck/should_compile/T10632.stderr
index 1733f0ae7a..0796146b17 100644
--- a/testsuite/tests/typecheck/should_compile/T10632.stderr
+++ b/testsuite/tests/typecheck/should_compile/T10632.stderr
@@ -1,5 +1,5 @@
 
 T10632.hs:4:1: warning: [-Wredundant-constraints]
-    • Redundant constraint: ?file1::String
+    • Redundant constraint: (?file1::String)
     • In the type signature for:
            f :: (?file1::String) => IO ()
diff --git a/testsuite/tests/typecheck/should_fail/ClassOperator.stderr b/testsuite/tests/typecheck/should_fail/ClassOperator.stderr
index 29ac2d240d..30791286c2 100644
--- a/testsuite/tests/typecheck/should_fail/ClassOperator.stderr
+++ b/testsuite/tests/typecheck/should_fail/ClassOperator.stderr
@@ -1,7 +1,7 @@
 
 ClassOperator.hs:12:3: error:
     • Could not deduce (a ><> b0)
-      from the context: a ><> b
+      from the context: (a ><> b)
         bound by the type signature for:
                    (**>) :: (a ><> b) => a -> a -> ()
         at ClassOperator.hs:12:3-44
@@ -14,7 +14,7 @@ ClassOperator.hs:12:3: error:
 
 ClassOperator.hs:12:3: error:
     • Could not deduce (a ><> b0)
-      from the context: a ><> b
+      from the context: (a ><> b)
         bound by the type signature for:
                    (**<) :: (a ><> b) => a -> a -> ()
         at ClassOperator.hs:12:3-44
@@ -27,7 +27,7 @@ ClassOperator.hs:12:3: error:
 
 ClassOperator.hs:12:3: error:
     • Could not deduce (a ><> b0)
-      from the context: a ><> b
+      from the context: (a ><> b)
         bound by the type signature for:
                    (>**) :: (a ><> b) => a -> a -> ()
         at ClassOperator.hs:12:3-44
@@ -40,7 +40,7 @@ ClassOperator.hs:12:3: error:
 
 ClassOperator.hs:12:3: error:
     • Could not deduce (a ><> b0)
-      from the context: a ><> b
+      from the context: (a ><> b)
         bound by the type signature for:
                    (<**) :: (a ><> b) => a -> a -> ()
         at ClassOperator.hs:12:3-44
diff --git a/testsuite/tests/typecheck/should_fail/IPFail.stderr b/testsuite/tests/typecheck/should_fail/IPFail.stderr
index 72c11b0c0d..0ba5bce32a 100644
--- a/testsuite/tests/typecheck/should_fail/IPFail.stderr
+++ b/testsuite/tests/typecheck/should_fail/IPFail.stderr
@@ -1,7 +1,7 @@
 
 IPFail.hs:6:18: error:
     • Could not deduce (Num Bool) arising from the literal ‘5’
-      from the context: ?x::Int
+      from the context: (?x::Int)
         bound by the type signature for:
                    f0 :: (?x::Int) => () -> Bool
         at IPFail.hs:5:1-31
diff --git a/testsuite/tests/typecheck/should_fail/T7019a.stderr b/testsuite/tests/typecheck/should_fail/T7019a.stderr
index a50fbcf240..9772b85e58 100644
--- a/testsuite/tests/typecheck/should_fail/T7019a.stderr
+++ b/testsuite/tests/typecheck/should_fail/T7019a.stderr
@@ -2,6 +2,6 @@
 T7019a.hs:11:1: error:
     • Illegal polymorphic type: forall b. Context (Associated a b)
       A constraint must be a monotype
-    • In the context: forall b. Context (Associated a b)
+    • In the context: (forall b. Context (Associated a b))
       While checking the super-classes of class ‘Class’
       In the class declaration for ‘Class’
diff --git a/testsuite/tests/typecheck/should_fail/T7525.stderr b/testsuite/tests/typecheck/should_fail/T7525.stderr
index 4d6f8d3a90..99b9c2861d 100644
--- a/testsuite/tests/typecheck/should_fail/T7525.stderr
+++ b/testsuite/tests/typecheck/should_fail/T7525.stderr
@@ -1,9 +1,9 @@
 
-T7525.hs:5:30:
-    Could not deduce: ?b::Bool
-      arising from a use of implicit parameter ‘?b’
-    from the context: ?a::Bool
-      bound by the implicit-parameter binding for ?a at T7525.hs:5:7-31
-    In the second argument of ‘(&&)’, namely ‘?b’
-    In the expression: ?a && ?b
-    In the expression: let ?a = True in ?a && ?b
+T7525.hs:5:30: error:
+    • Could not deduce: (?b::Bool)
+        arising from a use of implicit parameter ‘?b’
+      from the context: (?a::Bool)
+        bound by the implicit-parameter binding for ?a at T7525.hs:5:7-31
+    • In the second argument of ‘(&&)’, namely ‘?b’
+      In the expression: ?a && ?b
+      In the expression: let ?a = True in ?a && ?b
diff --git a/testsuite/tests/typecheck/should_fail/T8912.stderr b/testsuite/tests/typecheck/should_fail/T8912.stderr
index 4e4515e7a1..78fdd108dd 100644
--- a/testsuite/tests/typecheck/should_fail/T8912.stderr
+++ b/testsuite/tests/typecheck/should_fail/T8912.stderr
@@ -1,6 +1,6 @@
 
-T8912.hs:7:10:
-    Illegal implicit parameter ‘?imp::Int’
-    In the context: ?imp::Int
-    While checking an instance declaration
-    In the instance declaration for ‘C [a]’
+T8912.hs:7:10: error:
+    • Illegal implicit parameter ‘?imp::Int’
+    • In the context: (?imp::Int)
+      While checking an instance declaration
+      In the instance declaration for ‘C [a]’
diff --git a/testsuite/tests/typecheck/should_fail/tcfail041.stderr b/testsuite/tests/typecheck/should_fail/tcfail041.stderr
index fe116b5277..d2d3214d9e 100644
--- a/testsuite/tests/typecheck/should_fail/tcfail041.stderr
+++ b/testsuite/tests/typecheck/should_fail/tcfail041.stderr
@@ -1,6 +1,6 @@
 
-tcfail041.hs:5:1:
-    Illegal implicit parameter ‘?imp::Int’
-    In the context: ?imp::Int
-    While checking the super-classes of class ‘D’
-    In the class declaration for ‘D’
+tcfail041.hs:5:1: error:
+    • Illegal implicit parameter ‘?imp::Int’
+    • In the context: (?imp::Int)
+      While checking the super-classes of class ‘D’
+      In the class declaration for ‘D’
diff --git a/testsuite/tests/typecheck/should_fail/tcfail130.stderr b/testsuite/tests/typecheck/should_fail/tcfail130.stderr
index 7640031cbd..51f77d14c6 100644
--- a/testsuite/tests/typecheck/should_fail/tcfail130.stderr
+++ b/testsuite/tests/typecheck/should_fail/tcfail130.stderr
@@ -1,5 +1,6 @@
 
-tcfail130.hs:10:7:
-    Unbound implicit parameter ?x::Int arising from a use of ‘woggle’
-    In the expression: woggle 3
-    In an equation for ‘foo’: foo = woggle 3
+tcfail130.hs:10:7: error:
+    • Unbound implicit parameter (?x::Int)
+        arising from a use of ‘woggle’
+    • In the expression: woggle 3
+      In an equation for ‘foo’: foo = woggle 3
diff --git a/testsuite/tests/typecheck/should_fail/tcfail211.stderr b/testsuite/tests/typecheck/should_fail/tcfail211.stderr
index 7a5053a092..a88cc35507 100644
--- a/testsuite/tests/typecheck/should_fail/tcfail211.stderr
+++ b/testsuite/tests/typecheck/should_fail/tcfail211.stderr
@@ -1,12 +1,12 @@
 
 tcfail211.hs:5:1: error:
     • Illegal implicit parameter ‘?imp::Int’
-    • In the context: ?imp::Int
+    • In the context: (?imp::Int)
       While checking the super-classes of class ‘D’
       In the class declaration for ‘D’
 
 tcfail211.hs:8:10: error:
     • Illegal implicit parameter ‘?imp::Int’
-    • In the context: ?imp::Int
+    • In the context: (?imp::Int)
       While checking an instance declaration
       In the instance declaration for ‘D Int’
diff --git a/testsuite/tests/typecheck/should_run/tcrun045.stderr b/testsuite/tests/typecheck/should_run/tcrun045.stderr
index f6b1652e5b..19fca1096f 100644
--- a/testsuite/tests/typecheck/should_run/tcrun045.stderr
+++ b/testsuite/tests/typecheck/should_run/tcrun045.stderr
@@ -1,18 +1,18 @@
 
 tcrun045.hs:11:10: error:
     • Illegal implicit parameter ‘?imp::Int’
-    • In the context: ?imp::Int
+    • In the context: (?imp::Int)
       While checking an instance declaration
       In the instance declaration for ‘C Int’
 
 tcrun045.hs:24:1: error:
     • Illegal implicit parameter ‘?imp::Int’
-    • In the context: ?imp::Int
+    • In the context: (?imp::Int)
       While checking the super-classes of class ‘D’
       In the class declaration for ‘D’
 
 tcrun045.hs:27:10: error:
     • Illegal implicit parameter ‘?imp::Int’
-    • In the context: ?imp::Int
+    • In the context: (?imp::Int)
       While checking an instance declaration
       In the instance declaration for ‘D Int’