Merge branch 'master' into late-lam-lift

Silly conflicts because of new flags -- not sure how best to resolve/avoid this.

git is requiring my commit to mention 'submodule' for some reason?

Conflicts:
	compiler/main/DynFlags.hs

38 files changed, 291 insertions, 62 deletions

diff --git a/testsuite/tests/ghci/scripts/Defer02.stderr b/testsuite/tests/ghci/scripts/Defer02.stderr
index ed36a3eb3c..7635c8f804 100644
--- a/testsuite/tests/ghci/scripts/Defer02.stderr
+++ b/testsuite/tests/ghci/scripts/Defer02.stderr
@@ -84,13 +84,13 @@
       the type signature for k :: Int ~ Bool => Int -> Bool
     In the ambiguity check for: Int ~ Bool => Int -> Bool
     To defer the ambiguity check to use sites, enable AllowAmbiguousTypes
-    In the type signature for ‘k’: k :: Int ~ Bool => Int -> Bool
+    In the type signature for ‘k’: k :: (Int ~ Bool) => Int -> Bool
 
 ../../typecheck/should_run/Defer01.hs:45:6: Warning:
     Couldn't match expected type ‘Bool’ with actual type ‘Int’
     In the ambiguity check for: Int ~ Bool => Int -> Bool
     To defer the ambiguity check to use sites, enable AllowAmbiguousTypes
-    In the type signature for ‘k’: k :: Int ~ Bool => Int -> Bool
+    In the type signature for ‘k’: k :: (Int ~ Bool) => Int -> Bool
 
 ../../typecheck/should_run/Defer01.hs:45:6: Warning:
     Couldn't match type ‘Int’ with ‘Bool’
diff --git a/testsuite/tests/ghci/scripts/T2766.stdout b/testsuite/tests/ghci/scripts/T2766.stdout
index f8ee42ff6a..5bcbd9e75e 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/T4087.stdout b/testsuite/tests/ghci/scripts/T4087.stdout
index 3f600bd78d..2ca08aa449 100644
--- a/testsuite/tests/ghci/scripts/T4087.stdout
+++ b/testsuite/tests/ghci/scripts/T4087.stdout
@@ -1,4 +1,4 @@
-type role Equal nominal nominal
-data Equal a b where
-  Equal :: Equal a a
-  	-- Defined at T4087.hs:5:1
+type role Equal nominal nominal

+data Equal a b where

+  Equal :: Equal b b

+  	-- Defined at T4087.hs:5:1

diff --git a/testsuite/tests/ghci/scripts/T4175.stdout b/testsuite/tests/ghci/scripts/T4175.stdout
index 1f44bd1051..29bca027ce 100644
--- a/testsuite/tests/ghci/scripts/T4175.stdout
+++ b/testsuite/tests/ghci/scripts/T4175.stdout
@@ -1,18 +1,18 @@
 type family A a b :: * 	-- Defined at T4175.hs:7:1
-type instance A (B a) b -- Defined at T4175.hs:10:1
-type instance A (Maybe a) a -- Defined at T4175.hs:9:1
-type instance A Int Int -- Defined at T4175.hs:8:1
+type instance A (B a) b = () 	-- Defined at T4175.hs:10:1
+type instance A (Maybe a) a = a 	-- Defined at T4175.hs:9:1
+type instance A Int Int = () 	-- Defined at T4175.hs:8:1
 type role B nominal
 data family B a
   	-- Defined at T4175.hs:12:1
 instance G B -- Defined at T4175.hs:34:10
-data instance B () -- Defined at T4175.hs:13:15
-type instance A (B a) b -- Defined at T4175.hs:10:1
+data instance B () = MkB 	-- Defined at T4175.hs:13:15
+type instance A (B a) b = () 	-- Defined at T4175.hs:10:1
 class C a where
   type family D a b :: *
   	-- Defined at T4175.hs:16:5
-type D () () -- Defined at T4175.hs:22:5
-type D Int () -- Defined at T4175.hs:19:5
+type instance D () () = Bool 	-- Defined at T4175.hs:22:5
+type instance D Int () = String 	-- Defined at T4175.hs:19:5
 type family E a :: * where
     E () = Bool
     E Int = String
@@ -25,9 +25,9 @@ instance Eq () -- Defined in ‘GHC.Classes’
 instance Ord () -- Defined in ‘GHC.Classes’
 instance Read () -- Defined in ‘GHC.Read’
 instance Show () -- Defined in ‘GHC.Show’
-type D () () -- Defined at T4175.hs:22:5
-type D Int () -- Defined at T4175.hs:19:5
-data instance B () -- Defined at T4175.hs:13:15
+type instance D () () = Bool 	-- Defined at T4175.hs:22:5
+type instance D Int () = String 	-- Defined at T4175.hs:19:5
+data instance B () = MkB 	-- Defined at T4175.hs:13:15
 data Maybe a = Nothing | Just a 	-- Defined in ‘Data.Maybe’
 instance Eq a => Eq (Maybe a) -- Defined in ‘Data.Maybe’
 instance Monad Maybe -- Defined in ‘Data.Maybe’
@@ -35,7 +35,7 @@ instance Functor Maybe -- Defined in ‘Data.Maybe’
 instance Ord a => Ord (Maybe a) -- Defined in ‘Data.Maybe’
 instance Read a => Read (Maybe a) -- Defined in ‘GHC.Read’
 instance Show a => Show (Maybe a) -- Defined in ‘GHC.Show’
-type instance A (Maybe a) a -- Defined at T4175.hs:9:1
+type instance A (Maybe a) a = a 	-- Defined at T4175.hs:9:1
 data Int = I# Int# 	-- Defined in ‘GHC.Types’
 instance C Int -- Defined at T4175.hs:18:10
 instance Bounded Int -- Defined in ‘GHC.Enum’
@@ -47,7 +47,7 @@ instance Ord Int -- Defined in ‘GHC.Classes’
 instance Read Int -- Defined in ‘GHC.Read’
 instance Real Int -- Defined in ‘GHC.Real’
 instance Show Int -- Defined in ‘GHC.Show’
-type D Int () -- Defined at T4175.hs:19:5
-type instance A Int Int -- Defined at T4175.hs:8:1
+type instance D Int () = String 	-- Defined at T4175.hs:19:5
+type instance A Int Int = () 	-- Defined at T4175.hs:8:1
 class Z a 	-- Defined at T4175.hs:28:1
 instance F (Z a) -- Defined at T4175.hs:31:10
diff --git a/testsuite/tests/ghci/scripts/T5417.stdout b/testsuite/tests/ghci/scripts/T5417.stdout
index 73d1de932d..1085a1750f 100644
--- a/testsuite/tests/ghci/scripts/T5417.stdout
+++ b/testsuite/tests/ghci/scripts/T5417.stdout
@@ -6,4 +6,4 @@ class C.C1 a where
   type role C.F nominal
   data family C.F a
   	-- Defined at T5417a.hs:5:5
-data C.F (B1 a) -- Defined at T5417.hs:8:10
+data instance C.F (B1 a) = B2 a 	-- Defined at T5417.hs:8:10
diff --git a/testsuite/tests/ghci/scripts/T5979.stderr b/testsuite/tests/ghci/scripts/T5979.stderr
index fe6e012603..bbdba12305 100644
--- a/testsuite/tests/ghci/scripts/T5979.stderr
+++ b/testsuite/tests/ghci/scripts/T5979.stderr
@@ -1,4 +1,7 @@
 
 <no location info>:
     Could not find module ‘Control.Monad.Trans.State’
-    It is not a module in the current program, or in any known package.
+    Perhaps you meant
+      Control.Monad.Trans.State (from transformers-0.4.1.0@trans_ATJ404cg3uBDx7JJZaSn1I)
+      Control.Monad.Trans.Class (from transformers-0.4.1.0@trans_ATJ404cg3uBDx7JJZaSn1I)
+      Control.Monad.Trans.Cont (from transformers-0.4.1.0@trans_ATJ404cg3uBDx7JJZaSn1I)
diff --git a/testsuite/tests/ghci/scripts/T7730.script b/testsuite/tests/ghci/scripts/T7730.script
new file mode 100644
index 0000000000..f1e01ee1ef
--- /dev/null
+++ b/testsuite/tests/ghci/scripts/T7730.script
@@ -0,0 +1,7 @@
+:set -XPolyKinds
+data A x y
+:i A
+:kind A
+:set -XExistentialQuantification
+data T a = forall a . MkT a
+:info T
diff --git a/testsuite/tests/ghci/scripts/T7730.stdout b/testsuite/tests/ghci/scripts/T7730.stdout
new file mode 100644
index 0000000000..e3a08c19f4
--- /dev/null
+++ b/testsuite/tests/ghci/scripts/T7730.stdout
@@ -0,0 +1,8 @@
+type role A phantom phantom
+data A (x :: k) (y :: k1)
+  	-- Defined at <interactive>:3:1
+A :: k -> k1 -> *
+type role T phantom
+data T (a :: k) where
+  MkT :: forall (k :: BOX) (a :: k) a1. a1 -> T a
+  	-- Defined at <interactive>:7:1
diff --git a/testsuite/tests/ghci/scripts/T7873.stdout b/testsuite/tests/ghci/scripts/T7873.stdout
index 0167fb2eba..215757bb69 100644
--- a/testsuite/tests/ghci/scripts/T7873.stdout
+++ b/testsuite/tests/ghci/scripts/T7873.stdout
@@ -1,5 +1,6 @@
 data D1 where
-  MkD1 :: (forall (p :: k -> *) (a :: k). p a -> Int) -> D1
+  MkD1 :: (forall (k1 :: BOX) (p :: k1 -> *) (a :: k1). p a -> Int)
+          -> D1
   	-- Defined at <interactive>:3:1
 data D2 where
   MkD2 :: (forall (p :: k -> *) (a :: k). p a -> Int) -> D2
diff --git a/testsuite/tests/ghci/scripts/T7939.hs b/testsuite/tests/ghci/scripts/T7939.hs
index 93b90164c6..fbdf883b51 100644
--- a/testsuite/tests/ghci/scripts/T7939.hs
+++ b/testsuite/tests/ghci/scripts/T7939.hs
@@ -22,6 +22,6 @@ type family K a where
   K '[] = Nothing
   K (h ': t) = Just h
 
-type family L (a :: k) b :: k where
+type family L (a :: k) (b :: *) :: k where
   L Int Int = Bool
-  L Maybe Bool = IO
\ No newline at end of file
+  L Maybe Bool = IO
diff --git a/testsuite/tests/ghci/scripts/T7939.stdout b/testsuite/tests/ghci/scripts/T7939.stdout
index 9a88b5c294..feb890c578 100644
--- a/testsuite/tests/ghci/scripts/T7939.stdout
+++ b/testsuite/tests/ghci/scripts/T7939.stdout
@@ -3,21 +3,23 @@ class Foo (a :: k) where
   	-- Defined at T7939.hs:6:4
 Bar :: k -> * -> *
 type family F a :: * 	-- Defined at T7939.hs:8:1
-type instance F Int -- Defined at T7939.hs:9:1
+type instance F Int = Bool 	-- Defined at T7939.hs:9:1
 F :: * -> *
-type family G a :: * where G Int = Bool
+type family G a :: * where
+    G Int = Bool
   	-- Defined at T7939.hs:11:1
 G :: * -> *
-type family H (a :: Bool) :: Bool where H 'False = 'True
+type family H (a :: Bool) :: Bool where
+    H 'False = 'True
   	-- Defined at T7939.hs:14:1
 H :: Bool -> Bool
 type family J (a :: [k]) :: Bool where
-    J '[] = 'False
-    J (h : t) = 'True
+    J k '[] = 'False
+  forall (k :: BOX) (h :: k) (t :: [k]). J k (h : t) = 'True
   	-- Defined at T7939.hs:17:1
 J :: [k] -> Bool
 type family K (a :: [k]) :: Maybe k where
-    K '[] = 'Nothing
-    K (h : t) = 'Just h
+    K k '[] = 'Nothing
+  forall (k :: BOX) (h :: k) (t :: [k]). K k (h : t) = 'Just h
   	-- Defined at T7939.hs:21:1
 K :: [k] -> Maybe k
diff --git a/testsuite/tests/ghci/scripts/T8674.stdout b/testsuite/tests/ghci/scripts/T8674.stdout
index a4f5bbff6e..6c13176e66 100644
--- a/testsuite/tests/ghci/scripts/T8674.stdout
+++ b/testsuite/tests/ghci/scripts/T8674.stdout
@@ -1,5 +1,5 @@
 type role Sing nominal
 data family Sing (a :: k)
   	-- Defined at T8674.hs:4:1
-data instance Sing Bool -- Defined at T8674.hs:6:15
-data instance Sing a -- Defined at T8674.hs:5:15
+data instance Sing Bool = SBool 	-- Defined at T8674.hs:6:15
+data instance Sing a = SNil 	-- Defined at T8674.hs:5:15
diff --git a/testsuite/tests/ghci/scripts/T8931.script b/testsuite/tests/ghci/scripts/T8931.script
new file mode 100644
index 0000000000..152747681c
--- /dev/null
+++ b/testsuite/tests/ghci/scripts/T8931.script
@@ -0,0 +1,3 @@
+:m +Data.Typeable
+let {f :: Typeable a => (a->Bool) -> Bool; f _ = True}
+f (\x -> (x == 3))
diff --git a/testsuite/tests/ghci/scripts/T8931.stdout b/testsuite/tests/ghci/scripts/T8931.stdout
new file mode 100644
index 0000000000..0ca95142bb
--- /dev/null
+++ b/testsuite/tests/ghci/scripts/T8931.stdout
@@ -0,0 +1 @@
+True
diff --git a/testsuite/tests/ghci/scripts/T8959.script b/testsuite/tests/ghci/scripts/T8959.script
new file mode 100644
index 0000000000..124b2ab2f5
--- /dev/null
+++ b/testsuite/tests/ghci/scripts/T8959.script
@@ -0,0 +1,20 @@
+:set -XPatternGuards -XArrows -XRankNTypes
+
+:t lookup
+:t undefined :: (forall a. a -> a) -> a
+:t () >- () -< () >>- () -<< ()
+let fun foo | True <- () = ()
+
+:set -XUnicodeSyntax
+
+:t lookup
+:t undefined :: (forall a. a -> a) -> a
+:t () >- () -< () >>- () -<< ()
+let fun foo | True <- () = ()
+
+:set -XNoUnicodeSyntax
+
+:t lookup
+:t undefined :: (forall a. a -> a) -> a
+:t () >- () -< () >>- () -<< ()
+let fun foo | True <- () = ()
diff --git a/testsuite/tests/ghci/scripts/T8959.stderr b/testsuite/tests/ghci/scripts/T8959.stderr
new file mode 100644
index 0000000000..b3995c3365
--- /dev/null
+++ b/testsuite/tests/ghci/scripts/T8959.stderr
@@ -0,0 +1,36 @@
+
+<interactive>:1:1:
+    Arrow command found where an expression was expected:
+      () >- () -< () >>- () -<< ()
+
+<interactive>:7:15:
+    Couldn't match expected type ‘()’ with actual type ‘Bool’
+    In the pattern: True
+    In a stmt of a pattern guard for
+                   an equation for ‘fun’:
+      True <- ()
+    In an equation for ‘fun’: fun foo | True <- () = ()
+
+<interactive>:1:1:
+    Arrow command found where an expression was expected:
+      () ↣ () ↢ () ⤜ () ⤛ ()
+
+<interactive>:14:15:
+    Couldn't match expected type ‘()’ with actual type ‘Bool’
+    In the pattern: True
+    In a stmt of a pattern guard for
+                   an equation for ‘fun’:
+      True ← ()
+    In an equation for ‘fun’: fun foo | True ← () = ()
+
+<interactive>:1:1:
+    Arrow command found where an expression was expected:
+      () >- () -< () >>- () -<< ()
+
+<interactive>:21:15:
+    Couldn't match expected type ‘()’ with actual type ‘Bool’
+    In the pattern: True
+    In a stmt of a pattern guard for
+                   an equation for ‘fun’:
+      True <- ()
+    In an equation for ‘fun’: fun foo | True <- () = ()
diff --git a/testsuite/tests/ghci/scripts/T8959.stdout b/testsuite/tests/ghci/scripts/T8959.stdout
new file mode 100644
index 0000000000..4631732c55
--- /dev/null
+++ b/testsuite/tests/ghci/scripts/T8959.stdout
@@ -0,0 +1,6 @@
+lookup :: Eq a => a -> [(a, b)] -> Maybe b
+undefined :: (forall a. a -> a) -> a :: (forall a1. a1 -> a1) -> a
+lookup ∷ Eq a ⇒ a → [(a, b)] → Maybe b
+undefined :: (forall a. a -> a) -> a ∷ (∀ a1. a1 → a1) → a
+lookup :: Eq a => a -> [(a, b)] -> Maybe b
+undefined :: (forall a. a -> a) -> a :: (forall a1. a1 -> a1) -> a
diff --git a/testsuite/tests/ghci/scripts/T8959b.hs b/testsuite/tests/ghci/scripts/T8959b.hs
new file mode 100644
index 0000000000..064b2670a8
--- /dev/null
+++ b/testsuite/tests/ghci/scripts/T8959b.hs
@@ -0,0 +1,11 @@
+{-# LANGUAGE UnicodeSyntax, Arrows, RankNTypes #-}
+module T8959b where
+
+foo :: Int -> Int
+foo = ()
+
+bar :: ()
+bar = proc x -> do return -< x
+
+baz = () :: (forall a. a -> a) -> a
+
diff --git a/testsuite/tests/ghci/scripts/T8959b.script b/testsuite/tests/ghci/scripts/T8959b.script
new file mode 100644
index 0000000000..f3c23c97a3
--- /dev/null
+++ b/testsuite/tests/ghci/scripts/T8959b.script
@@ -0,0 +1 @@
+:l T8959b.hs
diff --git a/testsuite/tests/ghci/scripts/T8959b.stderr b/testsuite/tests/ghci/scripts/T8959b.stderr
new file mode 100644
index 0000000000..4f1ac7a97b
--- /dev/null
+++ b/testsuite/tests/ghci/scripts/T8959b.stderr
@@ -0,0 +1,16 @@
+
+T8959b.hs:5:7:
+    Couldn't match expected type ‘Int → Int’ with actual type ‘()’
+    In the expression: ()
+    In an equation for ‘foo’: foo = ()
+
+T8959b.hs:8:7:
+    Couldn't match expected type ‘()’ with actual type ‘t0 → m0 t0’
+    In the expression: proc x -> do { return ↢ x }
+    In an equation for ‘bar’: bar = proc x -> do { return ↢ x }
+
+T8959b.hs:10:7:
+    Couldn't match expected type ‘(∀ a2. a2 → a2) → a1’
+                with actual type ‘()’
+    In the expression: () ∷ (∀ a. a -> a) -> a
+    In an equation for ‘baz’: baz = () ∷ (∀ a. a -> a) -> a
diff --git a/testsuite/tests/ghci/scripts/T9086b.script b/testsuite/tests/ghci/scripts/T9086b.script
new file mode 100644
index 0000000000..d60156ad02
--- /dev/null
+++ b/testsuite/tests/ghci/scripts/T9086b.script
@@ -0,0 +1,2 @@
+let main = do { putStrLn "hello"; return "discarded" }
+:main
diff --git a/testsuite/tests/ghci/scripts/T9086b.stdout b/testsuite/tests/ghci/scripts/T9086b.stdout
new file mode 100644
index 0000000000..ce01362503
--- /dev/null
+++ b/testsuite/tests/ghci/scripts/T9086b.stdout
@@ -0,0 +1 @@
+hello
diff --git a/testsuite/tests/ghci/scripts/T9140.script b/testsuite/tests/ghci/scripts/T9140.script
new file mode 100644
index 0000000000..833ea87413
--- /dev/null
+++ b/testsuite/tests/ghci/scripts/T9140.script
@@ -0,0 +1,5 @@
+:set -XUnboxedTuples -XBangPatterns
+let a = (# 1 #)
+let a = (# 1, 3 #)
+:set -XBangPatterns
+let !a = (# 1, 3 #)
diff --git a/testsuite/tests/ghci/scripts/T9140.stdout b/testsuite/tests/ghci/scripts/T9140.stdout
new file mode 100644
index 0000000000..a5cb42f58a
--- /dev/null
+++ b/testsuite/tests/ghci/scripts/T9140.stdout
@@ -0,0 +1,14 @@
+
+<interactive>:3:5:
+    You can't mix polymorphic and unlifted bindings
+      a = (# 1 #)
+      Probable fix: use a bang pattern
+
+<interactive>:4:5:
+    You can't mix polymorphic and unlifted bindings
+      a = (# 1, 3 #)
+      Probable fix: use a bang pattern
+
+Top level:
+    GHCi can't bind a variable of unlifted type:
+      a :: (# Integer, Integer #)
diff --git a/testsuite/tests/ghci/scripts/T9181.script b/testsuite/tests/ghci/scripts/T9181.script
new file mode 100644
index 0000000000..b2239b9556
--- /dev/null
+++ b/testsuite/tests/ghci/scripts/T9181.script
@@ -0,0 +1 @@
+:browse GHC.TypeLits
diff --git a/testsuite/tests/ghci/scripts/T9181.stdout b/testsuite/tests/ghci/scripts/T9181.stdout
new file mode 100644
index 0000000000..e1ac00cc83
--- /dev/null
+++ b/testsuite/tests/ghci/scripts/T9181.stdout
@@ -0,0 +1,54 @@
+type family (GHC.TypeLits.*) (a :: GHC.TypeLits.Nat)
+                             (b :: GHC.TypeLits.Nat) ::
+  GHC.TypeLits.Nat
+type family (GHC.TypeLits.+) (a :: GHC.TypeLits.Nat)
+                             (b :: GHC.TypeLits.Nat) ::
+  GHC.TypeLits.Nat
+type family (GHC.TypeLits.-) (a :: GHC.TypeLits.Nat)
+                             (b :: GHC.TypeLits.Nat) ::
+  GHC.TypeLits.Nat
+type (GHC.TypeLits.<=) (x :: GHC.TypeLits.Nat)
+                       (y :: GHC.TypeLits.Nat) =
+  (x GHC.TypeLits.<=? y) ~ 'True
+type family (GHC.TypeLits.<=?) (a :: GHC.TypeLits.Nat)
+                               (b :: GHC.TypeLits.Nat) ::
+  Bool
+type family GHC.TypeLits.CmpNat (a :: GHC.TypeLits.Nat)
+                                (b :: GHC.TypeLits.Nat) ::
+  Ordering
+type family GHC.TypeLits.CmpSymbol (a :: GHC.TypeLits.Symbol)
+                                   (b :: GHC.TypeLits.Symbol) ::
+  Ordering
+class GHC.TypeLits.KnownNat (n :: GHC.TypeLits.Nat) where
+  GHC.TypeLits.natSing :: GHC.TypeLits.SNat n
+class GHC.TypeLits.KnownSymbol (n :: GHC.TypeLits.Symbol) where
+  GHC.TypeLits.symbolSing :: GHC.TypeLits.SSymbol n
+data GHC.TypeLits.Nat
+data GHC.TypeLits.SomeNat where
+  GHC.TypeLits.SomeNat :: GHC.TypeLits.KnownNat n =>
+                          (Data.Proxy.Proxy n) -> GHC.TypeLits.SomeNat
+data GHC.TypeLits.SomeSymbol where
+  GHC.TypeLits.SomeSymbol :: GHC.TypeLits.KnownSymbol n =>
+                             (Data.Proxy.Proxy n) -> GHC.TypeLits.SomeSymbol
+data GHC.TypeLits.Symbol
+type family (GHC.TypeLits.^) (a :: GHC.TypeLits.Nat)
+                             (b :: GHC.TypeLits.Nat) ::
+  GHC.TypeLits.Nat
+GHC.TypeLits.natVal ::
+  GHC.TypeLits.KnownNat n => proxy n -> Integer
+GHC.TypeLits.natVal' ::
+  GHC.TypeLits.KnownNat n => GHC.Prim.Proxy# n -> Integer
+GHC.TypeLits.sameNat ::
+  (GHC.TypeLits.KnownNat a, GHC.TypeLits.KnownNat b) =>
+  Data.Proxy.Proxy a
+  -> Data.Proxy.Proxy b -> Maybe (a Data.Type.Equality.:~: b)
+GHC.TypeLits.sameSymbol ::
+  (GHC.TypeLits.KnownSymbol a, GHC.TypeLits.KnownSymbol b) =>
+  Data.Proxy.Proxy a
+  -> Data.Proxy.Proxy b -> Maybe (a Data.Type.Equality.:~: b)
+GHC.TypeLits.someNatVal :: Integer -> Maybe GHC.TypeLits.SomeNat
+GHC.TypeLits.someSymbolVal :: String -> GHC.TypeLits.SomeSymbol
+GHC.TypeLits.symbolVal ::
+  GHC.TypeLits.KnownSymbol n => proxy n -> String
+GHC.TypeLits.symbolVal' ::
+  GHC.TypeLits.KnownSymbol n => GHC.Prim.Proxy# n -> String
diff --git a/testsuite/tests/ghci/scripts/all.T b/testsuite/tests/ghci/scripts/all.T
index 6c6923d42d..f02a3c0447 100755
--- a/testsuite/tests/ghci/scripts/all.T
+++ b/testsuite/tests/ghci/scripts/all.T
@@ -61,6 +61,7 @@ test('ghci041', normal, ghci_script, ['ghci041.script'])
 test('ghci042', normal, ghci_script, ['ghci042.script'])
 test('ghci043', normal, ghci_script, ['ghci043.script'])
 test('ghci044', normal, ghci_script, ['ghci044.script'])
+test('ghci044a', normal, ghci_script, ['ghci044a.script'])
 test('ghci045', normal, ghci_script, ['ghci045.script'])
 test('ghci046', normal, ghci_script, ['ghci046.script'])
 test('ghci047', normal, ghci_script, ['ghci047.script'])
@@ -113,7 +114,7 @@ test('T5564', normal, ghci_script, ['T5564.script'])
 test('Defer02', normal, ghci_script, ['Defer02.script'])
 test('T5820', normal, ghci_script, ['T5820.script'])
 test('T5836', normal, ghci_script, ['T5836.script'])
-test('T5979', normalise_slashes, ghci_script, ['T5979.script'])
+test('T5979', [reqlib('transformers'), normalise_slashes], ghci_script, ['T5979.script'])
 test('T5975a',
      [pre_cmd('touch föøbàr1.hs'),
       clean_cmd('rm föøbàr1.hs')],
@@ -147,6 +148,7 @@ test('T7627', normal, ghci_script, ['T7627.script'])
 test('T7627b', normal, ghci_script, ['T7627b.script'])
 test('T7586', normal, ghci_script, ['T7586.script'])
 test('T4175', normal, ghci_script, ['T4175.script'])
+test('T7730', combined_output, ghci_script, ['T7730.script'])
 test('T7872', normal, ghci_script, ['T7872.script'])
 test('T7873', normal, ghci_script, ['T7873.script'])
 test('T7939', normal, ghci_script, ['T7939.script'])
@@ -170,3 +172,9 @@ test('T8776', normal, ghci_script, ['T8776.script'])
 test('ghci059', normal, ghci_script, ['ghci059.script'])
 test('T8831', normal, ghci_script, ['T8831.script'])
 test('T8917', normal, ghci_script, ['T8917.script'])
+test('T8931', normal, ghci_script, ['T8931.script'])
+test('T8959', normal, ghci_script, ['T8959.script'])
+test('T8959b', expect_broken(8959), ghci_script, ['T8959b.script'])
+test('T9181', normal, ghci_script, ['T9181.script'])
+test('T9086b', normal, ghci_script, ['T9086b.script'])
+test('T9140', combined_output, ghci_script, ['T9140.script'])
diff --git a/testsuite/tests/ghci/scripts/ghci016.hs b/testsuite/tests/ghci/scripts/ghci016.hs
index 2740a66517..0c86f02d0f 100644
--- a/testsuite/tests/ghci/scripts/ghci016.hs
+++ b/testsuite/tests/ghci/scripts/ghci016.hs
@@ -13,6 +13,7 @@ instance Num T where
     (*)    = error "urk"
     abs    = error "urk"
     signum = error "urk"
+    negate = error "urk"
 
 -- Typing 3 at the ghci prompt should print T
 
diff --git a/testsuite/tests/ghci/scripts/ghci025.stdout b/testsuite/tests/ghci/scripts/ghci025.stdout
index 9308dd3f39..9cc88b8a07 100644
--- a/testsuite/tests/ghci/scripts/ghci025.stdout
+++ b/testsuite/tests/ghci/scripts/ghci025.stdout
@@ -11,7 +11,7 @@ class C a b where
   c4 :: a1 -> b
 c1 :: (C a b, N b) => a -> b
 c2 :: (C a b, N b, S b) => a -> b
-c3 :: C a b => forall a1. a1 -> b
+c3 :: C a b => forall a. a -> b
 c4 :: C a b => forall a1. a1 -> b
 -- imported via Control.Monad
 class Monad m => MonadPlus (m :: * -> *) where
@@ -69,7 +69,7 @@ class C a b where
   c4 :: a1 -> b
 c1 :: (C a b, N b) => a -> b
 c2 :: (C a b, N b, S b) => a -> b
-c3 :: C a b => forall a1. a1 -> b
+c3 :: C a b => forall a. a -> b
 c4 :: C a b => forall a1. a1 -> b
 :browse! T -- with -fprint-explicit-foralls
 -- defined locally
@@ -83,7 +83,7 @@ class C a b where
   c4 :: forall a1. a1 -> b
 c1 :: forall a b. (C a b, N b) => a -> b
 c2 :: forall a b. (C a b, N b, S b) => a -> b
-c3 :: forall a b. C a b => forall a1. a1 -> b
+c3 :: forall a b. C a b => forall a. a -> b
 c4 :: forall a b. C a b => forall a1. a1 -> b
 -- test :browse! <target> relative to different contexts
 :browse! Ghci025C -- from *Ghci025C>
diff --git a/testsuite/tests/ghci/scripts/ghci031.stdout b/testsuite/tests/ghci/scripts/ghci031.stdout
index d90cc7aa00..796433e1b7 100644
--- a/testsuite/tests/ghci/scripts/ghci031.stdout
+++ b/testsuite/tests/ghci/scripts/ghci031.stdout
@@ -1 +1,3 @@
-data Eq a => D a = C a 	-- Defined at ghci031.hs:7:1
+type role D nominal
+data Eq a => D a = C a
+  	-- Defined at ghci031.hs:7:1
diff --git a/testsuite/tests/ghci/scripts/ghci044.script b/testsuite/tests/ghci/scripts/ghci044.script
index 7af66bb935..d6f12ada6e 100644
--- a/testsuite/tests/ghci/scripts/ghci044.script
+++ b/testsuite/tests/ghci/scripts/ghci044.script
@@ -1,10 +1,15 @@
 --Testing flexible and Overlapping instances
-class C a where { f :: a -> Int; f _ = 3 }
-instance C Int where { f = id }
-instance C [Int]
+class C a where { f :: a -> String; f _ = "Default" }
+instance C Int where { f _ = "Zeroth" }
 :set -XFlexibleInstances
-instance C [Int]
-instance C a => C [a] where f xs = length xs
--- ***This should be an overlapping instances error!***
-:set -XOverlappingInstances
-instance C a => C [a] where f xs = length xs
+instance C [Int] where f _ = "First"
+f [3::Int]
+instance C a => C [a] where f xs = "Second"
+f [4::Int]  -- ***This should be an overlapping instances error!***
+instance {-# OVERLAPPABLE #-} C a => C [a] where f xs = "Third"
+f [5::Int]  -- Should be fine
+instance {-# OVERLAPPABLE #-} C a => C [a] where f xs = "Fourth"
+f [6::Int]  -- Should be fine too, overrides
+instance C Bool where { f _ = "Bool" }
+f [True]  -- Should be fine too, overrides
+
diff --git a/testsuite/tests/ghci/scripts/ghci044.stderr b/testsuite/tests/ghci/scripts/ghci044.stderr
index c319dd1f1c..9bc8df9994 100644
--- a/testsuite/tests/ghci/scripts/ghci044.stderr
+++ b/testsuite/tests/ghci/scripts/ghci044.stderr
@@ -1,13 +1,8 @@
 
-<interactive>:5:10:
-    Illegal instance declaration for ‘C [Int]’
-      (All instance types must be of the form (T a1 ... an)
-       where a1 ... an are *distinct type variables*,
-       and each type variable appears at most once in the instance head.
-       Use FlexibleInstances if you want to disable this.)
-    In the instance declaration for ‘C [Int]’
-
-<interactive>:7:10:
-    Overlapping instance declarations:
-      instance C [Int] -- Defined at <interactive>:7:10
+<interactive>:9:1:
+    Overlapping instances for C [Int] arising from a use of ‘f’
+    Matching instances:
+      instance C [Int] -- Defined at <interactive>:6:10
       instance C a => C [a] -- Defined at <interactive>:8:10
+    In the expression: f [4 :: Int]
+    In an equation for ‘it’: it = f [4 :: Int]
diff --git a/testsuite/tests/ghci/scripts/ghci044.stdout b/testsuite/tests/ghci/scripts/ghci044.stdout
new file mode 100644
index 0000000000..eadd22f710
--- /dev/null
+++ b/testsuite/tests/ghci/scripts/ghci044.stdout
@@ -0,0 +1,4 @@
+"First"

+"First"

+"First"

+"Fourth"

diff --git a/testsuite/tests/ghci/scripts/ghci044a.hs b/testsuite/tests/ghci/scripts/ghci044a.hs
new file mode 100644
index 0000000000..ac400d3ef9
--- /dev/null
+++ b/testsuite/tests/ghci/scripts/ghci044a.hs
@@ -0,0 +1,9 @@
+--Testing flexible and Overlapping instances
+class C a where { f :: a -> String; f _ = 3 }
+instance C Int where { f = id }
+:set -XFlexibleInstances
+instance C [Int] where f _ = "First"
+f [3::Int]
+-- Should override the identical one preceding
+instance C [Int] where f _ = "Second"
+f [3::Int]
diff --git a/testsuite/tests/ghci/scripts/ghci044a.script b/testsuite/tests/ghci/scripts/ghci044a.script
new file mode 100644
index 0000000000..d78c5c25bc
--- /dev/null
+++ b/testsuite/tests/ghci/scripts/ghci044a.script
@@ -0,0 +1,9 @@
+--Testing flexible and Overlapping instances
+class C a where { f :: a -> String; f _ = "Default" }
+instance C Int where { f _ = "Zeroth" }
+:set -XFlexibleInstances
+instance C [Int] where f _ = "First"
+f [3::Int]
+-- Should override the identical one preceding
+instance C [Int] where f _ = "Second"
+f [3::Int]
diff --git a/testsuite/tests/ghci/scripts/ghci044a.stdout b/testsuite/tests/ghci/scripts/ghci044a.stdout
new file mode 100644
index 0000000000..fe475f4745
--- /dev/null
+++ b/testsuite/tests/ghci/scripts/ghci044a.stdout
@@ -0,0 +1,2 @@
+"First"
+"Second"
diff --git a/testsuite/tests/ghci/scripts/ghci047.script b/testsuite/tests/ghci/scripts/ghci047.script
index 49d93047f6..70cc5181d8 100644
--- a/testsuite/tests/ghci/scripts/ghci047.script
+++ b/testsuite/tests/ghci/scripts/ghci047.script
@@ -1,7 +1,6 @@
 --Testing GADTs, type families as well as a ton of crazy type stuff
 :set -XGADTs
 :set -XTypeFamilies
-:set -XOverlappingInstances
 :set -XFunctionalDependencies
 :set -XFlexibleContexts
 :set -XFlexibleInstances
@@ -22,8 +21,9 @@ data HTrue
 data HFalse
 
 class TypeEq x y b | x y -> b
-instance (HTrue ~ b)  => TypeEq x x b
-instance (HFalse ~ b) => TypeEq x y b
+instance {-# OVERLAPS #-} (HTrue ~ b)  => TypeEq x x b
+instance {-# OVERLAPS #-} (HTrue ~ b)  => TypeEq x x b
+instance {-# OVERLAPS #-} (HFalse ~ b) => TypeEq x y b
 
 type family Or a b
 type instance Or HTrue  HTrue  = HTrue
diff --git a/testsuite/tests/ghci/scripts/ghci059.stdout b/testsuite/tests/ghci/scripts/ghci059.stdout
index 6b2c8f886e..ffc893f363 100644
--- a/testsuite/tests/ghci/scripts/ghci059.stdout
+++ b/testsuite/tests/ghci/scripts/ghci059.stdout
@@ -1,4 +1,6 @@
 type role Coercible representational representational
 class Coercible (a :: k) (b :: k)
   	-- Defined in ‘GHC.Types’
-coerce :: Coercible a b => a -> b 	-- Defined in ‘GHC.Prim’
+coerce ::
+  forall (k :: BOX) (a :: k) (b :: k). Coercible a b => a -> b
+  	-- Defined in ‘GHC.Prim’