Always display inferred variables using braces

We now always show "forall {a}. T" for inferred variables,
previously this was controlled by -fprint-explicit-foralls.

This implements part 1 of https://github.com/ghc-proposals/ghc-proposals/pull/179.

Part of GHC ticket #16320.

Furthermore, when printing a levity restriction error, we now display
the HsWrap of the expression. This lets users see the full elaboration with
-fprint-typechecker-elaboration (see also #17670)

17 files changed, 199 insertions, 191 deletions

diff --git a/testsuite/tests/partial-sigs/should_compile/Defaulting2MROff.stderr b/testsuite/tests/partial-sigs/should_compile/Defaulting2MROff.stderr
index 37ada9e6bc..4332d07a03 100644
--- a/testsuite/tests/partial-sigs/should_compile/Defaulting2MROff.stderr
+++ b/testsuite/tests/partial-sigs/should_compile/Defaulting2MROff.stderr
@@ -1,5 +1,5 @@
 TYPE SIGNATURES
-  bravo :: forall _. Num _ => _
+  bravo :: forall {_}. Num _ => _
 Dependent modules: []
 Dependent packages: [base-4.13.0.0, ghc-prim-0.6.1,
                      integer-gmp-1.0.2.0]
diff --git a/testsuite/tests/partial-sigs/should_compile/Defaulting2MROn.stderr b/testsuite/tests/partial-sigs/should_compile/Defaulting2MROn.stderr
index 37ada9e6bc..4332d07a03 100644
--- a/testsuite/tests/partial-sigs/should_compile/Defaulting2MROn.stderr
+++ b/testsuite/tests/partial-sigs/should_compile/Defaulting2MROn.stderr
@@ -1,5 +1,5 @@
 TYPE SIGNATURES
-  bravo :: forall _. Num _ => _
+  bravo :: forall {_}. Num _ => _
 Dependent modules: []
 Dependent packages: [base-4.13.0.0, ghc-prim-0.6.1,
                      integer-gmp-1.0.2.0]
diff --git a/testsuite/tests/partial-sigs/should_compile/Either.stderr b/testsuite/tests/partial-sigs/should_compile/Either.stderr
index d7a636413c..f5f54d209e 100644
--- a/testsuite/tests/partial-sigs/should_compile/Either.stderr
+++ b/testsuite/tests/partial-sigs/should_compile/Either.stderr
@@ -1,5 +1,5 @@
 TYPE SIGNATURES
-  barry :: forall _. _ -> (Either [Char] _, Either [Char] _)
+  barry :: forall {_}. _ -> (Either [Char] _, Either [Char] _)
 Dependent modules: []
 Dependent packages: [base-4.13.0.0, ghc-prim-0.6.1,
                      integer-gmp-1.0.2.0]
diff --git a/testsuite/tests/partial-sigs/should_compile/Every.stderr b/testsuite/tests/partial-sigs/should_compile/Every.stderr
index 3e33dcbf48..d9f69686e1 100644
--- a/testsuite/tests/partial-sigs/should_compile/Every.stderr
+++ b/testsuite/tests/partial-sigs/should_compile/Every.stderr
@@ -1,5 +1,5 @@
 TYPE SIGNATURES
-  every :: forall t. (t -> Bool) -> [t] -> Bool
+  every :: forall {t}. (t -> Bool) -> [t] -> Bool
 Dependent modules: []
 Dependent packages: [base-4.13.0.0, ghc-prim-0.6.1,
                      integer-gmp-1.0.2.0]
diff --git a/testsuite/tests/partial-sigs/should_compile/EveryNamed.stderr b/testsuite/tests/partial-sigs/should_compile/EveryNamed.stderr
index 3cbaff90ac..28c25b80b6 100644
--- a/testsuite/tests/partial-sigs/should_compile/EveryNamed.stderr
+++ b/testsuite/tests/partial-sigs/should_compile/EveryNamed.stderr
@@ -1,5 +1,5 @@
 TYPE SIGNATURES
-  every :: forall _. (_ -> Bool) -> [_] -> Bool
+  every :: forall {_}. (_ -> Bool) -> [_] -> Bool
 Dependent modules: []
 Dependent packages: [base-4.13.0.0, ghc-prim-0.6.1,
                      integer-gmp-1.0.2.0]
diff --git a/testsuite/tests/partial-sigs/should_compile/ExtraConstraints3.stderr b/testsuite/tests/partial-sigs/should_compile/ExtraConstraints3.stderr
index 064c995300..3b94743dbb 100644
--- a/testsuite/tests/partial-sigs/should_compile/ExtraConstraints3.stderr
+++ b/testsuite/tests/partial-sigs/should_compile/ExtraConstraints3.stderr
@@ -1,231 +1,239 @@
 TYPE SIGNATURES
-  !! :: forall a. [a] -> Int -> a
-  $ :: forall a b. (a -> b) -> a -> b
-  $! :: forall a b. (a -> b) -> a -> b
+  !! :: forall {a}. [a] -> Int -> a
+  $ :: forall {a} {b}. (a -> b) -> a -> b
+  $! :: forall {a} {b}. (a -> b) -> a -> b
   && :: Bool -> Bool -> Bool
-  * :: forall a. Num a => a -> a -> a
-  ** :: forall a. Floating a => a -> a -> a
-  + :: forall a. Num a => a -> a -> a
-  ++ :: forall a. [a] -> [a] -> [a]
-  - :: forall a. Num a => a -> a -> a
-  . :: forall b c a. (b -> c) -> (a -> b) -> a -> c
-  / :: forall a. Fractional a => a -> a -> a
-  /= :: forall a. Eq a => a -> a -> Bool
-  < :: forall a. Ord a => a -> a -> Bool
-  <= :: forall a. Ord a => a -> a -> Bool
+  * :: forall {a}. Num a => a -> a -> a
+  ** :: forall {a}. Floating a => a -> a -> a
+  + :: forall {a}. Num a => a -> a -> a
+  ++ :: forall {a}. [a] -> [a] -> [a]
+  - :: forall {a}. Num a => a -> a -> a
+  . :: forall {b} {c} {a}. (b -> c) -> (a -> b) -> a -> c
+  / :: forall {a}. Fractional a => a -> a -> a
+  /= :: forall {a}. Eq a => a -> a -> Bool
+  < :: forall {a}. Ord a => a -> a -> Bool
+  <= :: forall {a}. Ord a => a -> a -> Bool
   =<< ::
-    forall (m :: * -> *) a b. Monad m => (a -> m b) -> m a -> m b
-  == :: forall a. Eq a => a -> a -> Bool
-  > :: forall a. Ord a => a -> a -> Bool
-  >= :: forall a. Ord a => a -> a -> Bool
-  >> :: forall (m :: * -> *) a b. Monad m => m a -> m b -> m b
+    forall {m :: * -> *} {a} {b}. Monad m => (a -> m b) -> m a -> m b
+  == :: forall {a}. Eq a => a -> a -> Bool
+  > :: forall {a}. Ord a => a -> a -> Bool
+  >= :: forall {a}. Ord a => a -> a -> Bool
+  >> :: forall {m :: * -> *} {a} {b}. Monad m => m a -> m b -> m b
   >>= ::
-    forall (m :: * -> *) a b. Monad m => m a -> (a -> m b) -> m b
-  ^ :: forall b a. (Integral b, Num a) => a -> b -> a
-  ^^ :: forall a b. (Fractional a, Integral b) => a -> b -> a
-  abs :: forall a. Num a => a -> a
-  acos :: forall a. Floating a => a -> a
-  acosh :: forall a. Floating a => a -> a
+    forall {m :: * -> *} {a} {b}. Monad m => m a -> (a -> m b) -> m b
+  ^ :: forall {b} {a}. (Integral b, Num a) => a -> b -> a
+  ^^ :: forall {a} {b}. (Fractional a, Integral b) => a -> b -> a
+  abs :: forall {a}. Num a => a -> a
+  acos :: forall {a}. Floating a => a -> a
+  acosh :: forall {a}. Floating a => a -> a
   all ::
-    forall (t :: * -> *) a. P.Foldable t => (a -> Bool) -> t a -> Bool
-  and :: forall (t :: * -> *). P.Foldable t => t Bool -> Bool
+    forall {t :: * -> *} {a}.
+    P.Foldable t =>
+    (a -> Bool) -> t a -> Bool
+  and :: forall {t :: * -> *}. P.Foldable t => t Bool -> Bool
   any ::
-    forall (t :: * -> *) a. P.Foldable t => (a -> Bool) -> t a -> Bool
+    forall {t :: * -> *} {a}.
+    P.Foldable t =>
+    (a -> Bool) -> t a -> Bool
   appendFile :: FilePath -> String -> IO ()
-  asTypeOf :: forall a. a -> a -> a
-  asin :: forall a. Floating a => a -> a
-  asinh :: forall a. Floating a => a -> a
-  atan :: forall a. Floating a => a -> a
-  atan2 :: forall a. RealFloat a => a -> a -> a
-  atanh :: forall a. Floating a => a -> a
-  break :: forall a. (a -> Bool) -> [a] -> ([a], [a])
-  ceiling :: forall a b. (RealFrac a, Integral b) => a -> b
-  compare :: forall a. Ord a => a -> a -> Ordering
-  concat :: forall (t :: * -> *) a. P.Foldable t => t [a] -> [a]
+  asTypeOf :: forall {a}. a -> a -> a
+  asin :: forall {a}. Floating a => a -> a
+  asinh :: forall {a}. Floating a => a -> a
+  atan :: forall {a}. Floating a => a -> a
+  atan2 :: forall {a}. RealFloat a => a -> a -> a
+  atanh :: forall {a}. Floating a => a -> a
+  break :: forall {a}. (a -> Bool) -> [a] -> ([a], [a])
+  ceiling :: forall {a} {b}. (RealFrac a, Integral b) => a -> b
+  compare :: forall {a}. Ord a => a -> a -> Ordering
+  concat :: forall {t :: * -> *} {a}. P.Foldable t => t [a] -> [a]
   concatMap ::
-    forall (t :: * -> *) a b. P.Foldable t => (a -> [b]) -> t a -> [b]
-  const :: forall a b. a -> b -> a
-  cos :: forall a. Floating a => a -> a
-  cosh :: forall a. Floating a => a -> a
-  curry :: forall a b c. ((a, b) -> c) -> a -> b -> c
-  cycle :: forall a. [a] -> [a]
-  decodeFloat :: forall a. RealFloat a => a -> (Integer, Int)
-  div :: forall a. Integral a => a -> a -> a
-  divMod :: forall a. Integral a => a -> a -> (a, a)
-  drop :: forall a. Int -> [a] -> [a]
-  dropWhile :: forall a. (a -> Bool) -> [a] -> [a]
-  either :: forall a c b. (a -> c) -> (b -> c) -> Either a b -> c
+    forall {t :: * -> *} {a} {b}.
+    P.Foldable t =>
+    (a -> [b]) -> t a -> [b]
+  const :: forall {a} {b}. a -> b -> a
+  cos :: forall {a}. Floating a => a -> a
+  cosh :: forall {a}. Floating a => a -> a
+  curry :: forall {a} {b} {c}. ((a, b) -> c) -> a -> b -> c
+  cycle :: forall {a}. [a] -> [a]
+  decodeFloat :: forall {a}. RealFloat a => a -> (Integer, Int)
+  div :: forall {a}. Integral a => a -> a -> a
+  divMod :: forall {a}. Integral a => a -> a -> (a, a)
+  drop :: forall {a}. Int -> [a] -> [a]
+  dropWhile :: forall {a}. (a -> Bool) -> [a] -> [a]
+  either ::
+    forall {a} {c} {b}. (a -> c) -> (b -> c) -> Either a b -> c
   elem ::
-    forall (t :: * -> *) a. (P.Foldable t, Eq a) => a -> t a -> Bool
-  encodeFloat :: forall a. RealFloat a => Integer -> Int -> a
-  enumFrom :: forall a. Enum a => a -> [a]
-  enumFromThen :: forall a. Enum a => a -> a -> [a]
-  enumFromThenTo :: forall a. Enum a => a -> a -> a -> [a]
-  enumFromTo :: forall a. Enum a => a -> a -> [a]
-  error :: forall a. [Char] -> a
-  even :: forall a. Integral a => a -> Bool
-  exp :: forall a. Floating a => a -> a
-  exponent :: forall a. RealFloat a => a -> Int
-  fail :: forall (m :: * -> *) a. P.MonadFail m => String -> m a
-  filter :: forall a. (a -> Bool) -> [a] -> [a]
-  flip :: forall a b c. (a -> b -> c) -> b -> a -> c
-  floatDigits :: forall a. RealFloat a => a -> Int
-  floatRadix :: forall a. RealFloat a => a -> Integer
-  floatRange :: forall a. RealFloat a => a -> (Int, Int)
-  floor :: forall a b. (RealFrac a, Integral b) => a -> b
+    forall {t :: * -> *} {a}. (P.Foldable t, Eq a) => a -> t a -> Bool
+  encodeFloat :: forall {a}. RealFloat a => Integer -> Int -> a
+  enumFrom :: forall {a}. Enum a => a -> [a]
+  enumFromThen :: forall {a}. Enum a => a -> a -> [a]
+  enumFromThenTo :: forall {a}. Enum a => a -> a -> a -> [a]
+  enumFromTo :: forall {a}. Enum a => a -> a -> [a]
+  error :: forall {a}. [Char] -> a
+  even :: forall {a}. Integral a => a -> Bool
+  exp :: forall {a}. Floating a => a -> a
+  exponent :: forall {a}. RealFloat a => a -> Int
+  fail :: forall {m :: * -> *} {a}. P.MonadFail m => String -> m a
+  filter :: forall {a}. (a -> Bool) -> [a] -> [a]
+  flip :: forall {a} {b} {c}. (a -> b -> c) -> b -> a -> c
+  floatDigits :: forall {a}. RealFloat a => a -> Int
+  floatRadix :: forall {a}. RealFloat a => a -> Integer
+  floatRange :: forall {a}. RealFloat a => a -> (Int, Int)
+  floor :: forall {a} {b}. (RealFrac a, Integral b) => a -> b
   fmap ::
-    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
+    forall {f :: * -> *} {a} {b}. Functor f => (a -> b) -> f a -> f b
   foldl ::
-    forall (t :: * -> *) b a.
+    forall {t :: * -> *} {b} {a}.
     P.Foldable t =>
     (b -> a -> b) -> b -> t a -> b
   foldl1 ::
-    forall (t :: * -> *) a. P.Foldable t => (a -> a -> a) -> t a -> a
+    forall {t :: * -> *} {a}. P.Foldable t => (a -> a -> a) -> t a -> a
   foldr ::
-    forall (t :: * -> *) a b.
+    forall {t :: * -> *} {a} {b}.
     P.Foldable t =>
     (a -> b -> b) -> b -> t a -> b
   foldr1 ::
-    forall (t :: * -> *) a. P.Foldable t => (a -> a -> a) -> t a -> a
-  fromEnum :: forall a. Enum a => a -> Int
-  fromInteger :: forall a. Num a => Integer -> a
-  fromIntegral :: forall a b. (Integral a, Num b) => a -> b
-  fromRational :: forall a. Fractional a => Rational -> a
-  fst :: forall a b. (a, b) -> a
-  gcd :: forall a. Integral a => a -> a -> a
+    forall {t :: * -> *} {a}. P.Foldable t => (a -> a -> a) -> t a -> a
+  fromEnum :: forall {a}. Enum a => a -> Int
+  fromInteger :: forall {a}. Num a => Integer -> a
+  fromIntegral :: forall {a} {b}. (Integral a, Num b) => a -> b
+  fromRational :: forall {a}. Fractional a => Rational -> a
+  fst :: forall {a} {b}. (a, b) -> a
+  gcd :: forall {a}. Integral a => a -> a -> a
   getChar :: IO Char
   getContents :: IO String
   getLine :: IO String
-  head :: forall a. [a] -> a
-  id :: forall a. a -> a
-  init :: forall a. [a] -> [a]
+  head :: forall {a}. [a] -> a
+  id :: forall {a}. a -> a
+  init :: forall {a}. [a] -> [a]
   interact :: (String -> String) -> IO ()
-  ioError :: forall a. IOError -> IO a
-  isDenormalized :: forall a. RealFloat a => a -> Bool
-  isIEEE :: forall a. RealFloat a => a -> Bool
-  isInfinite :: forall a. RealFloat a => a -> Bool
-  isNaN :: forall a. RealFloat a => a -> Bool
-  isNegativeZero :: forall a. RealFloat a => a -> Bool
-  iterate :: forall a. (a -> a) -> a -> [a]
-  last :: forall a. [a] -> a
-  lcm :: forall a. Integral a => a -> a -> a
-  length :: forall (t :: * -> *) a. P.Foldable t => t a -> Int
+  ioError :: forall {a}. IOError -> IO a
+  isDenormalized :: forall {a}. RealFloat a => a -> Bool
+  isIEEE :: forall {a}. RealFloat a => a -> Bool
+  isInfinite :: forall {a}. RealFloat a => a -> Bool
+  isNaN :: forall {a}. RealFloat a => a -> Bool
+  isNegativeZero :: forall {a}. RealFloat a => a -> Bool
+  iterate :: forall {a}. (a -> a) -> a -> [a]
+  last :: forall {a}. [a] -> a
+  lcm :: forall {a}. Integral a => a -> a -> a
+  length :: forall {t :: * -> *} {a}. P.Foldable t => t a -> Int
   lex :: ReadS String
   lines :: String -> [String]
-  log :: forall a. Floating a => a -> a
-  logBase :: forall a. Floating a => a -> a -> a
-  lookup :: forall a b. Eq a => a -> [(a, b)] -> Maybe b
-  map :: forall a b. (a -> b) -> [a] -> [b]
+  log :: forall {a}. Floating a => a -> a
+  logBase :: forall {a}. Floating a => a -> a -> a
+  lookup :: forall {a} {b}. Eq a => a -> [(a, b)] -> Maybe b
+  map :: forall {a} {b}. (a -> b) -> [a] -> [b]
   mapM ::
-    forall (t :: * -> *) (m :: * -> *) a b.
+    forall {t :: * -> *} {m :: * -> *} {a} {b}.
     (P.Traversable t, Monad m) =>
     (a -> m b) -> t a -> m (t b)
   mapM_ ::
-    forall (t :: * -> *) (m :: * -> *) a b.
+    forall {t :: * -> *} {m :: * -> *} {a} {b}.
     (P.Foldable t, Monad m) =>
     (a -> m b) -> t a -> m ()
-  max :: forall a. Ord a => a -> a -> a
-  maxBound :: forall _. Bounded _ => _
+  max :: forall {a}. Ord a => a -> a -> a
+  maxBound :: forall {_}. Bounded _ => _
   maximum ::
-    forall (t :: * -> *) a. (P.Foldable t, Ord a) => t a -> a
-  maybe :: forall b a. b -> (a -> b) -> Maybe a -> b
-  min :: forall a. Ord a => a -> a -> a
-  minBound :: forall _. Bounded _ => _
+    forall {t :: * -> *} {a}. (P.Foldable t, Ord a) => t a -> a
+  maybe :: forall {b} {a}. b -> (a -> b) -> Maybe a -> b
+  min :: forall {a}. Ord a => a -> a -> a
+  minBound :: forall {_}. Bounded _ => _
   minimum ::
-    forall (t :: * -> *) a. (P.Foldable t, Ord a) => t a -> a
-  mod :: forall a. Integral a => a -> a -> a
-  negate :: forall a. Num a => a -> a
+    forall {t :: * -> *} {a}. (P.Foldable t, Ord a) => t a -> a
+  mod :: forall {a}. Integral a => a -> a -> a
+  negate :: forall {a}. Num a => a -> a
   not :: Bool -> Bool
   notElem ::
-    forall (t :: * -> *) a. (P.Foldable t, Eq a) => a -> t a -> Bool
-  null :: forall (t :: * -> *) a. P.Foldable t => t a -> Bool
-  odd :: forall a. Integral a => a -> Bool
-  or :: forall (t :: * -> *). P.Foldable t => t Bool -> Bool
+    forall {t :: * -> *} {a}. (P.Foldable t, Eq a) => a -> t a -> Bool
+  null :: forall {t :: * -> *} {a}. P.Foldable t => t a -> Bool
+  odd :: forall {a}. Integral a => a -> Bool
+  or :: forall {t :: * -> *}. P.Foldable t => t Bool -> Bool
   otherwise :: Bool
-  pi :: forall _. Floating _ => _
-  pred :: forall a. Enum a => a -> a
-  print :: forall a. Show a => a -> IO ()
+  pi :: forall {_}. Floating _ => _
+  pred :: forall {a}. Enum a => a -> a
+  print :: forall {a}. Show a => a -> IO ()
   product ::
-    forall (t :: * -> *) a. (P.Foldable t, Num a) => t a -> a
+    forall {t :: * -> *} {a}. (P.Foldable t, Num a) => t a -> a
   properFraction ::
-    forall a b. (RealFrac a, Integral b) => a -> (b, a)
+    forall {a} {b}. (RealFrac a, Integral b) => a -> (b, a)
   putChar :: Char -> IO ()
   putStr :: String -> IO ()
   putStrLn :: String -> IO ()
-  quot :: forall a. Integral a => a -> a -> a
-  quotRem :: forall a. Integral a => a -> a -> (a, a)
-  read :: forall a. Read a => String -> a
+  quot :: forall {a}. Integral a => a -> a -> a
+  quotRem :: forall {a}. Integral a => a -> a -> (a, a)
+  read :: forall {a}. Read a => String -> a
   readFile :: FilePath -> IO String
-  readIO :: forall a. Read a => String -> IO a
-  readList :: forall a. Read a => ReadS [a]
-  readLn :: forall a. Read a => IO a
-  readParen :: forall a. Bool -> ReadS a -> ReadS a
-  reads :: forall a. Read a => ReadS a
-  readsPrec :: forall a. Read a => Int -> ReadS a
-  realToFrac :: forall a b. (Real a, Fractional b) => a -> b
-  recip :: forall a. Fractional a => a -> a
-  rem :: forall a. Integral a => a -> a -> a
-  repeat :: forall a. a -> [a]
-  replicate :: forall a. Int -> a -> [a]
-  return :: forall (m :: * -> *) a. Monad m => a -> m a
-  reverse :: forall a. [a] -> [a]
-  round :: forall a b. (RealFrac a, Integral b) => a -> b
-  scaleFloat :: forall a. RealFloat a => Int -> a -> a
-  scanl :: forall b a. (b -> a -> b) -> b -> [a] -> [b]
-  scanl1 :: forall a. (a -> a -> a) -> [a] -> [a]
-  scanr :: forall a b. (a -> b -> b) -> b -> [a] -> [b]
-  scanr1 :: forall a. (a -> a -> a) -> [a] -> [a]
-  seq :: forall a b. a -> b -> b
+  readIO :: forall {a}. Read a => String -> IO a
+  readList :: forall {a}. Read a => ReadS [a]
+  readLn :: forall {a}. Read a => IO a
+  readParen :: forall {a}. Bool -> ReadS a -> ReadS a
+  reads :: forall {a}. Read a => ReadS a
+  readsPrec :: forall {a}. Read a => Int -> ReadS a
+  realToFrac :: forall {a} {b}. (Real a, Fractional b) => a -> b
+  recip :: forall {a}. Fractional a => a -> a
+  rem :: forall {a}. Integral a => a -> a -> a
+  repeat :: forall {a}. a -> [a]
+  replicate :: forall {a}. Int -> a -> [a]
+  return :: forall {m :: * -> *} {a}. Monad m => a -> m a
+  reverse :: forall {a}. [a] -> [a]
+  round :: forall {a} {b}. (RealFrac a, Integral b) => a -> b
+  scaleFloat :: forall {a}. RealFloat a => Int -> a -> a
+  scanl :: forall {b} {a}. (b -> a -> b) -> b -> [a] -> [b]
+  scanl1 :: forall {a}. (a -> a -> a) -> [a] -> [a]
+  scanr :: forall {a} {b}. (a -> b -> b) -> b -> [a] -> [b]
+  scanr1 :: forall {a}. (a -> a -> a) -> [a] -> [a]
+  seq :: forall {a} {b}. a -> b -> b
   sequence ::
-    forall (t :: * -> *) (m :: * -> *) a.
+    forall {t :: * -> *} {m :: * -> *} {a}.
     (P.Traversable t, Monad m) =>
     t (m a) -> m (t a)
   sequence_ ::
-    forall (t :: * -> *) (m :: * -> *) a.
+    forall {t :: * -> *} {m :: * -> *} {a}.
     (P.Foldable t, Monad m) =>
     t (m a) -> m ()
-  show :: forall a. Show a => a -> String
+  show :: forall {a}. Show a => a -> String
   showChar :: Char -> ShowS
-  showList :: forall a. Show a => [a] -> ShowS
+  showList :: forall {a}. Show a => [a] -> ShowS
   showParen :: Bool -> ShowS -> ShowS
   showString :: String -> ShowS
-  shows :: forall a. Show a => a -> ShowS
-  showsPrec :: forall a. Show a => Int -> a -> ShowS
-  significand :: forall a. RealFloat a => a -> a
-  signum :: forall a. Num a => a -> a
-  sin :: forall a. Floating a => a -> a
-  sinh :: forall a. Floating a => a -> a
-  snd :: forall a b. (a, b) -> b
-  span :: forall a. (a -> Bool) -> [a] -> ([a], [a])
-  splitAt :: forall a. Int -> [a] -> ([a], [a])
-  sqrt :: forall a. Floating a => a -> a
-  subtract :: forall a. Num a => a -> a -> a
-  succ :: forall a. Enum a => a -> a
-  sum :: forall (t :: * -> *) a. (P.Foldable t, Num a) => t a -> a
-  tail :: forall a. [a] -> [a]
-  take :: forall a. Int -> [a] -> [a]
-  takeWhile :: forall a. (a -> Bool) -> [a] -> [a]
-  tan :: forall a. Floating a => a -> a
-  tanh :: forall a. Floating a => a -> a
-  toEnum :: forall a. Enum a => Int -> a
-  toInteger :: forall a. Integral a => a -> Integer
-  toRational :: forall a. Real a => a -> Rational
-  truncate :: forall a b. (RealFrac a, Integral b) => a -> b
-  uncurry :: forall a b c. (a -> b -> c) -> (a, b) -> c
-  undefined :: forall _. _
+  shows :: forall {a}. Show a => a -> ShowS
+  showsPrec :: forall {a}. Show a => Int -> a -> ShowS
+  significand :: forall {a}. RealFloat a => a -> a
+  signum :: forall {a}. Num a => a -> a
+  sin :: forall {a}. Floating a => a -> a
+  sinh :: forall {a}. Floating a => a -> a
+  snd :: forall {a} {b}. (a, b) -> b
+  span :: forall {a}. (a -> Bool) -> [a] -> ([a], [a])
+  splitAt :: forall {a}. Int -> [a] -> ([a], [a])
+  sqrt :: forall {a}. Floating a => a -> a
+  subtract :: forall {a}. Num a => a -> a -> a
+  succ :: forall {a}. Enum a => a -> a
+  sum :: forall {t :: * -> *} {a}. (P.Foldable t, Num a) => t a -> a
+  tail :: forall {a}. [a] -> [a]
+  take :: forall {a}. Int -> [a] -> [a]
+  takeWhile :: forall {a}. (a -> Bool) -> [a] -> [a]
+  tan :: forall {a}. Floating a => a -> a
+  tanh :: forall {a}. Floating a => a -> a
+  toEnum :: forall {a}. Enum a => Int -> a
+  toInteger :: forall {a}. Integral a => a -> Integer
+  toRational :: forall {a}. Real a => a -> Rational
+  truncate :: forall {a} {b}. (RealFrac a, Integral b) => a -> b
+  uncurry :: forall {a} {b} {c}. (a -> b -> c) -> (a, b) -> c
+  undefined :: forall {_}. _
   unlines :: [String] -> String
-  until :: forall a. (a -> Bool) -> (a -> a) -> a -> a
+  until :: forall {a}. (a -> Bool) -> (a -> a) -> a -> a
   unwords :: [String] -> String
-  unzip :: forall a b. [(a, b)] -> ([a], [b])
-  unzip3 :: forall a b c. [(a, b, c)] -> ([a], [b], [c])
+  unzip :: forall {a} {b}. [(a, b)] -> ([a], [b])
+  unzip3 :: forall {a} {b} {c}. [(a, b, c)] -> ([a], [b], [c])
   userError :: String -> IOError
   words :: String -> [String]
   writeFile :: FilePath -> String -> IO ()
-  zip :: forall a b. [a] -> [b] -> [(a, b)]
-  zip3 :: forall a b c. [a] -> [b] -> [c] -> [(a, b, c)]
-  zipWith :: forall a b c. (a -> b -> c) -> [a] -> [b] -> [c]
+  zip :: forall {a} {b}. [a] -> [b] -> [(a, b)]
+  zip3 :: forall {a} {b} {c}. [a] -> [b] -> [c] -> [(a, b, c)]
+  zipWith :: forall {a} {b} {c}. (a -> b -> c) -> [a] -> [b] -> [c]
   zipWith3 ::
-    forall a b c d. (a -> b -> c -> d) -> [a] -> [b] -> [c] -> [d]
+    forall {a} {b} {c} {d}.
+    (a -> b -> c -> d) -> [a] -> [b] -> [c] -> [d]
   || :: Bool -> Bool -> Bool
 Dependent modules: []
 Dependent packages: [base-4.13.0.0, ghc-prim-0.6.1,
diff --git a/testsuite/tests/partial-sigs/should_compile/Meltdown.stderr b/testsuite/tests/partial-sigs/should_compile/Meltdown.stderr
index 025fa95a42..6380befcc2 100644
--- a/testsuite/tests/partial-sigs/should_compile/Meltdown.stderr
+++ b/testsuite/tests/partial-sigs/should_compile/Meltdown.stderr
@@ -1,7 +1,7 @@
 TYPE SIGNATURES
   isMeltdown :: forall param1 param2. NukeMonad param1 param2 Bool
   unlessMeltdown ::
-    forall param1 param2.
+    forall {param1} {param2}.
     NukeMonad param1 param2 () -> NukeMonad param1 param2 ()
 TYPE CONSTRUCTORS
   data type NukeMonad{3} :: * -> * -> * -> *
diff --git a/testsuite/tests/partial-sigs/should_compile/PatBind.stderr b/testsuite/tests/partial-sigs/should_compile/PatBind.stderr
index de26dc9d80..1f71b4f434 100644
--- a/testsuite/tests/partial-sigs/should_compile/PatBind.stderr
+++ b/testsuite/tests/partial-sigs/should_compile/PatBind.stderr
@@ -1,5 +1,5 @@
 TYPE SIGNATURES
-  foo :: forall a. a -> a
+  foo :: forall {a}. a -> a
 Dependent modules: []
 Dependent packages: [base-4.13.0.0, ghc-prim-0.6.1,
                      integer-gmp-1.0.2.0]
diff --git a/testsuite/tests/partial-sigs/should_compile/ShowNamed.stderr b/testsuite/tests/partial-sigs/should_compile/ShowNamed.stderr
index 86054ed585..8ca152fd92 100644
--- a/testsuite/tests/partial-sigs/should_compile/ShowNamed.stderr
+++ b/testsuite/tests/partial-sigs/should_compile/ShowNamed.stderr
@@ -1,5 +1,5 @@
 TYPE SIGNATURES
-  showTwo :: forall a. Show a => a -> String
+  showTwo :: forall {a}. Show a => a -> String
 Dependent modules: []
 Dependent packages: [base-4.13.0.0, ghc-prim-0.6.1,
                      integer-gmp-1.0.2.0]
diff --git a/testsuite/tests/partial-sigs/should_compile/SimpleGen.stderr b/testsuite/tests/partial-sigs/should_compile/SimpleGen.stderr
index 34903a93cf..49e98e3b0d 100644
--- a/testsuite/tests/partial-sigs/should_compile/SimpleGen.stderr
+++ b/testsuite/tests/partial-sigs/should_compile/SimpleGen.stderr
@@ -1,5 +1,5 @@
 TYPE SIGNATURES
-  bar :: forall _. _ -> Bool
+  bar :: forall {_}. _ -> Bool
 Dependent modules: []
 Dependent packages: [base-4.13.0.0, ghc-prim-0.6.1,
                      integer-gmp-1.0.2.0]
diff --git a/testsuite/tests/partial-sigs/should_compile/SkipMany.stderr b/testsuite/tests/partial-sigs/should_compile/SkipMany.stderr
index da0aa8ed9e..4a205f9ca5 100644
--- a/testsuite/tests/partial-sigs/should_compile/SkipMany.stderr
+++ b/testsuite/tests/partial-sigs/should_compile/SkipMany.stderr
@@ -1,6 +1,6 @@
 TYPE SIGNATURES
   skipMany ::
-    forall tok st a. GenParser tok st a -> GenParser tok st ()
+    forall {tok} {st} {a}. GenParser tok st a -> GenParser tok st ()
   skipMany' ::
     forall tok st a. GenParser tok st a -> GenParser tok st ()
 TYPE CONSTRUCTORS
diff --git a/testsuite/tests/partial-sigs/should_compile/Uncurry.stderr b/testsuite/tests/partial-sigs/should_compile/Uncurry.stderr
index 68bec65094..0499a2eb93 100644
--- a/testsuite/tests/partial-sigs/should_compile/Uncurry.stderr
+++ b/testsuite/tests/partial-sigs/should_compile/Uncurry.stderr
@@ -1,5 +1,5 @@
 TYPE SIGNATURES
-  unc :: forall _1 _2 _3. (_1 -> _2 -> _3) -> (_1, _2) -> _3
+  unc :: forall {_1} {_2} {_3}. (_1 -> _2 -> _3) -> (_1, _2) -> _3
 Dependent modules: []
 Dependent packages: [base-4.13.0.0, ghc-prim-0.6.1,
                      integer-gmp-1.0.2.0]
diff --git a/testsuite/tests/partial-sigs/should_compile/UncurryNamed.stderr b/testsuite/tests/partial-sigs/should_compile/UncurryNamed.stderr
index 9d5f8e20be..62ae68aef0 100644
--- a/testsuite/tests/partial-sigs/should_compile/UncurryNamed.stderr
+++ b/testsuite/tests/partial-sigs/should_compile/UncurryNamed.stderr
@@ -1,5 +1,5 @@
 TYPE SIGNATURES
-  unc :: forall a b _. (a -> b -> _) -> (a, b) -> _
+  unc :: forall {a} {b} {_}. (a -> b -> _) -> (a, b) -> _
 Dependent modules: []
 Dependent packages: [base-4.13.0.0, ghc-prim-0.6.1,
                      integer-gmp-1.0.2.0]
diff --git a/testsuite/tests/partial-sigs/should_compile/WarningWildcardInstantiations.stderr b/testsuite/tests/partial-sigs/should_compile/WarningWildcardInstantiations.stderr
index 4dbb77b300..8cfb1f2fe0 100644
--- a/testsuite/tests/partial-sigs/should_compile/WarningWildcardInstantiations.stderr
+++ b/testsuite/tests/partial-sigs/should_compile/WarningWildcardInstantiations.stderr
@@ -1,6 +1,6 @@
 TYPE SIGNATURES
-  bar :: forall t _. t -> (t -> _) -> _
-  foo :: forall a. (Show a, Enum a) => a -> String
+  bar :: forall {t} {_}. t -> (t -> _) -> _
+  foo :: forall {a}. (Show a, Enum a) => a -> String
 Dependent modules: []
 Dependent packages: [base-4.13.0.0, ghc-prim-0.6.1,
                      integer-gmp-1.0.2.0]
diff --git a/testsuite/tests/partial-sigs/should_fail/NamedExtraConstraintsWildcard.stderr b/testsuite/tests/partial-sigs/should_fail/NamedExtraConstraintsWildcard.stderr
index c573747c02..84d61eda91 100644
--- a/testsuite/tests/partial-sigs/should_fail/NamedExtraConstraintsWildcard.stderr
+++ b/testsuite/tests/partial-sigs/should_fail/NamedExtraConstraintsWildcard.stderr
@@ -3,9 +3,9 @@ NamedExtraConstraintsWildcard.hs:5:1: error:
     • Could not deduce: _0
       from the context: (Eq a, _)
         bound by the inferred type for ‘foo’:
-                   forall a (_ :: Constraint). (Eq a, _) => a -> a
+                   forall a {_ :: Constraint}. (Eq a, _) => a -> a
         at NamedExtraConstraintsWildcard.hs:5:1-15
     • In the ambiguity check for the inferred type for ‘foo’
       To defer the ambiguity check to use sites, enable AllowAmbiguousTypes
       When checking the inferred type
-        foo :: forall a (_ :: Constraint). (Eq a, _) => a -> a
+        foo :: forall a {_ :: Constraint}. (Eq a, _) => a -> a
diff --git a/testsuite/tests/partial-sigs/should_fail/NamedWildcardsNotInMonotype.stderr b/testsuite/tests/partial-sigs/should_fail/NamedWildcardsNotInMonotype.stderr
index 89b71e5959..6a1d0edbb4 100644
--- a/testsuite/tests/partial-sigs/should_fail/NamedWildcardsNotInMonotype.stderr
+++ b/testsuite/tests/partial-sigs/should_fail/NamedWildcardsNotInMonotype.stderr
@@ -3,10 +3,10 @@ NamedWildcardsNotInMonotype.hs:5:1: error:
     • Could not deduce (Eq _0)
       from the context: (Show a, Eq _, Eq a)
         bound by the inferred type for ‘foo’:
-                   forall a _. (Show a, Eq _, Eq a) => a -> a -> String
+                   forall {a} {_}. (Show a, Eq _, Eq a) => a -> a -> String
         at NamedWildcardsNotInMonotype.hs:5:1-33
       The type variable ‘_0’ is ambiguous
     • In the ambiguity check for the inferred type for ‘foo’
       To defer the ambiguity check to use sites, enable AllowAmbiguousTypes
       When checking the inferred type
-        foo :: forall a _. (Show a, Eq _, Eq a) => a -> a -> String
+        foo :: forall {a} {_}. (Show a, Eq _, Eq a) => a -> a -> String
diff --git a/testsuite/tests/partial-sigs/should_fail/T14584a.stderr b/testsuite/tests/partial-sigs/should_fail/T14584a.stderr
index 5687dcec51..8c98b76ae2 100644
--- a/testsuite/tests/partial-sigs/should_fail/T14584a.stderr
+++ b/testsuite/tests/partial-sigs/should_fail/T14584a.stderr
@@ -14,7 +14,7 @@ T14584a.hs:12:14: warning: [-Wpartial-type-signatures (in -Wdefault)]
     • Found type wildcard ‘_’ standing for ‘m -> m’
       Where: ‘m’, ‘k’ are rigid type variables bound by
                the type signature for:
-                 f :: forall k2 (m :: k2). ()
+                 f :: forall {k2} (m :: k2). ()
                at T14584a.hs:11:1-17
     • In an expression type signature: _
       In the expression: id @m :: _