Require ScopedTypeVariables+TypeApplications to use type applications in patterns

Fixes #19109.

30 files changed, 51 insertions, 21 deletions

diff --git a/testsuite/tests/hiefile/should_compile/ScopesBug.hs b/testsuite/tests/hiefile/should_compile/ScopesBug.hs
index ea87d308d4..268216ad6e 100644
--- a/testsuite/tests/hiefile/should_compile/ScopesBug.hs
+++ b/testsuite/tests/hiefile/should_compile/ScopesBug.hs
@@ -3,6 +3,7 @@
 {-# LANGUAGE RecordWildCards #-}
 {-# LANGUAGE ScopedTypeVariables #-}
 {-# LANGUAGE PolyKinds #-}
+{-# LANGUAGE TypeApplications #-}
 
 module ScopesBug where
 
diff --git a/testsuite/tests/typecheck/should_compile/TyAppPat_Existential.hs b/testsuite/tests/typecheck/should_compile/TyAppPat_Existential.hs
index 7411ba07ee..6c3963655e 100644
--- a/testsuite/tests/typecheck/should_compile/TyAppPat_Existential.hs
+++ b/testsuite/tests/typecheck/should_compile/TyAppPat_Existential.hs
@@ -1,6 +1,7 @@
 {-# LANGUAGE TypeApplications #-}
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE ExistentialQuantification #-}
+{-# LANGUAGE ScopedTypeVariables #-}
 
 module Main where
 
diff --git a/testsuite/tests/typecheck/should_compile/TyAppPat_ExistentialMulti.hs b/testsuite/tests/typecheck/should_compile/TyAppPat_ExistentialMulti.hs
index 7e207c312a..7fe9021dc2 100644
--- a/testsuite/tests/typecheck/should_compile/TyAppPat_ExistentialMulti.hs
+++ b/testsuite/tests/typecheck/should_compile/TyAppPat_ExistentialMulti.hs
@@ -1,6 +1,7 @@
 {-# LANGUAGE TypeApplications #-}
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE ExistentialQuantification #-}
+{-# LANGUAGE ScopedTypeVariables #-}
 
 module Main where
 
diff --git a/testsuite/tests/typecheck/should_compile/TyAppPat_Mixed.hs b/testsuite/tests/typecheck/should_compile/TyAppPat_Mixed.hs
index 47812d994d..8c50ec96c4 100644
--- a/testsuite/tests/typecheck/should_compile/TyAppPat_Mixed.hs
+++ b/testsuite/tests/typecheck/should_compile/TyAppPat_Mixed.hs
@@ -1,6 +1,7 @@
 {-# LANGUAGE TypeApplications #-}
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE ExistentialQuantification #-}
+{-# LANGUAGE ScopedTypeVariables #-}
 
 module Main where
 
diff --git a/testsuite/tests/typecheck/should_compile/TyAppPat_TH.hs b/testsuite/tests/typecheck/should_compile/TyAppPat_TH.hs
index aeaa4fcac3..4bc7fbec7e 100644
--- a/testsuite/tests/typecheck/should_compile/TyAppPat_TH.hs
+++ b/testsuite/tests/typecheck/should_compile/TyAppPat_TH.hs
@@ -2,6 +2,7 @@
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE ExistentialQuantification #-}
 {-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE ScopedTypeVariables #-}
 
 module Main where
 
diff --git a/testsuite/tests/typecheck/should_compile/TyAppPat_Universal.hs b/testsuite/tests/typecheck/should_compile/TyAppPat_Universal.hs
index 7a74ff8403..51b3d5d404 100644
--- a/testsuite/tests/typecheck/should_compile/TyAppPat_Universal.hs
+++ b/testsuite/tests/typecheck/should_compile/TyAppPat_Universal.hs
@@ -1,6 +1,7 @@
 {-# LANGUAGE TypeApplications #-}
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE ExistentialQuantification #-}
+{-# LANGUAGE ScopedTypeVariables #-}
 
 module Main where
 
diff --git a/testsuite/tests/typecheck/should_compile/TyAppPat_UniversalMulti1.hs b/testsuite/tests/typecheck/should_compile/TyAppPat_UniversalMulti1.hs
index cccee20cb1..c2f67e0c94 100644
--- a/testsuite/tests/typecheck/should_compile/TyAppPat_UniversalMulti1.hs
+++ b/testsuite/tests/typecheck/should_compile/TyAppPat_UniversalMulti1.hs
@@ -1,6 +1,7 @@
 {-# LANGUAGE TypeApplications #-}
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE ExistentialQuantification #-}
+{-# LANGUAGE ScopedTypeVariables #-}
 
 module Main where
 import Data.Maybe
diff --git a/testsuite/tests/typecheck/should_compile/TyAppPat_UniversalMulti2.hs b/testsuite/tests/typecheck/should_compile/TyAppPat_UniversalMulti2.hs
index f01b606799..ac45474ad3 100644
--- a/testsuite/tests/typecheck/should_compile/TyAppPat_UniversalMulti2.hs
+++ b/testsuite/tests/typecheck/should_compile/TyAppPat_UniversalMulti2.hs
@@ -2,6 +2,7 @@
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE ExistentialQuantification #-}
 {-# LANGUAGE KindSignatures #-}
+{-# LANGUAGE ScopedTypeVariables #-}
 
 module Main where
 
diff --git a/testsuite/tests/typecheck/should_compile/TyAppPat_UniversalMulti3.hs b/testsuite/tests/typecheck/should_compile/TyAppPat_UniversalMulti3.hs
index 89fb88d5fe..1cebed6561 100644
--- a/testsuite/tests/typecheck/should_compile/TyAppPat_UniversalMulti3.hs
+++ b/testsuite/tests/typecheck/should_compile/TyAppPat_UniversalMulti3.hs
@@ -1,6 +1,7 @@
 {-# LANGUAGE TypeApplications #-}
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE ExistentialQuantification #-}
+{-# LANGUAGE ScopedTypeVariables #-}
 
 module Main where
 
diff --git a/testsuite/tests/typecheck/should_compile/TyAppPat_UniversalNested.hs b/testsuite/tests/typecheck/should_compile/TyAppPat_UniversalNested.hs
index e7f5522776..4a8764b9a2 100644
--- a/testsuite/tests/typecheck/should_compile/TyAppPat_UniversalNested.hs
+++ b/testsuite/tests/typecheck/should_compile/TyAppPat_UniversalNested.hs
@@ -1,6 +1,7 @@
 {-# LANGUAGE TypeApplications #-}
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE ExistentialQuantification #-}
+{-# LANGUAGE ScopedTypeVariables #-}
 
 module Main where
 
diff --git a/testsuite/tests/typecheck/should_compile/TyAppPat_Wildcard.hs b/testsuite/tests/typecheck/should_compile/TyAppPat_Wildcard.hs
index 722a9b4d63..22827f57bb 100644
--- a/testsuite/tests/typecheck/should_compile/TyAppPat_Wildcard.hs
+++ b/testsuite/tests/typecheck/should_compile/TyAppPat_Wildcard.hs
@@ -2,6 +2,7 @@
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE ExistentialQuantification #-}
 {-# LANGUAGE PartialTypeSignatures #-}
+{-# LANGUAGE ScopedTypeVariables #-}
 
 module Main where
 
diff --git a/testsuite/tests/typecheck/should_fail/T19109.hs b/testsuite/tests/typecheck/should_fail/T19109.hs
new file mode 100644
index 0000000000..614f883b52
--- /dev/null
+++ b/testsuite/tests/typecheck/should_fail/T19109.hs
@@ -0,0 +1,5 @@
+module T19109 where
+
+import Data.Functor.Identity
+
+f (Identity @Int x) = x
diff --git a/testsuite/tests/typecheck/should_fail/T19109.stderr b/testsuite/tests/typecheck/should_fail/T19109.stderr
new file mode 100644
index 0000000000..25ce535835
--- /dev/null
+++ b/testsuite/tests/typecheck/should_fail/T19109.stderr
@@ -0,0 +1,4 @@
+
+T19109.hs:5:4: error:
+    Illegal visible type application in a pattern: ‘@Int’
+      Both ScopedTypeVariables and TypeApplications are required to use this feature
diff --git a/testsuite/tests/typecheck/should_fail/TyAppPat_ExistentialEscape.hs b/testsuite/tests/typecheck/should_fail/TyAppPat_ExistentialEscape.hs
index d163874c8e..7ebf23ddc5 100644
--- a/testsuite/tests/typecheck/should_fail/TyAppPat_ExistentialEscape.hs
+++ b/testsuite/tests/typecheck/should_fail/TyAppPat_ExistentialEscape.hs
@@ -1,6 +1,7 @@
 {-# LANGUAGE TypeApplications #-}
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE ExistentialQuantification #-}
+{-# LANGUAGE ScopedTypeVariables #-}
 
 module Main where
 
diff --git a/testsuite/tests/typecheck/should_fail/TyAppPat_ExistentialEscape.stderr b/testsuite/tests/typecheck/should_fail/TyAppPat_ExistentialEscape.stderr
index 06f7c3adca..2efb51a5c1 100644
--- a/testsuite/tests/typecheck/should_fail/TyAppPat_ExistentialEscape.stderr
+++ b/testsuite/tests/typecheck/should_fail/TyAppPat_ExistentialEscape.stderr
@@ -1,15 +1,15 @@
 
-TyAppPat_ExistentialEscape.hs:9:20: error:
+TyAppPat_ExistentialEscape.hs:10:20: error:
     • Couldn't match expected type ‘p’ with actual type ‘a’
       ‘a’ is a rigid type variable bound by
         a pattern with constructor: Some :: forall a. a -> Some,
         in an equation for ‘foo’
-        at TyAppPat_ExistentialEscape.hs:9:6-14
+        at TyAppPat_ExistentialEscape.hs:10:6-14
       ‘p’ is a rigid type variable bound by
         the inferred type of foo :: Some -> p
-        at TyAppPat_ExistentialEscape.hs:9:1-26
+        at TyAppPat_ExistentialEscape.hs:10:1-26
     • In the expression: x :: a
       In an equation for ‘foo’: foo (Some @a x) = (x :: a)
     • Relevant bindings include
-        x :: a (bound at TyAppPat_ExistentialEscape.hs:9:14)
-        foo :: Some -> p (bound at TyAppPat_ExistentialEscape.hs:9:1)
+        x :: a (bound at TyAppPat_ExistentialEscape.hs:10:14)
+        foo :: Some -> p (bound at TyAppPat_ExistentialEscape.hs:10:1)
diff --git a/testsuite/tests/typecheck/should_fail/TyAppPat_NonlinearMultiAppPat.hs b/testsuite/tests/typecheck/should_fail/TyAppPat_NonlinearMultiAppPat.hs
index db50abb7a5..efdcf517f9 100644
--- a/testsuite/tests/typecheck/should_fail/TyAppPat_NonlinearMultiAppPat.hs
+++ b/testsuite/tests/typecheck/should_fail/TyAppPat_NonlinearMultiAppPat.hs
@@ -1,6 +1,7 @@
 {-# LANGUAGE TypeApplications #-}
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE ExistentialQuantification #-}
+{-# LANGUAGE ScopedTypeVariables #-}
 
 module Main where
 
diff --git a/testsuite/tests/typecheck/should_fail/TyAppPat_NonlinearMultiAppPat.stderr b/testsuite/tests/typecheck/should_fail/TyAppPat_NonlinearMultiAppPat.stderr
index 4b891df797..87655cb6cf 100644
--- a/testsuite/tests/typecheck/should_fail/TyAppPat_NonlinearMultiAppPat.stderr
+++ b/testsuite/tests/typecheck/should_fail/TyAppPat_NonlinearMultiAppPat.stderr
@@ -1,4 +1,4 @@
 
-TyAppPat_NonlinearMultiAppPat.hs:12:6: error:
+TyAppPat_NonlinearMultiAppPat.hs:13:6: error:
     Type variable ‘a’ is already in scope.
     Type applications in patterns must bind fresh variables, without shadowing.
diff --git a/testsuite/tests/typecheck/should_fail/TyAppPat_NonlinearMultiPat.hs b/testsuite/tests/typecheck/should_fail/TyAppPat_NonlinearMultiPat.hs
index 557ebb1d97..bba6d08a11 100644
--- a/testsuite/tests/typecheck/should_fail/TyAppPat_NonlinearMultiPat.hs
+++ b/testsuite/tests/typecheck/should_fail/TyAppPat_NonlinearMultiPat.hs
@@ -1,6 +1,7 @@
 {-# LANGUAGE TypeApplications #-}
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE ExistentialQuantification #-}
+{-# LANGUAGE ScopedTypeVariables #-}
 
 module Main where
 
diff --git a/testsuite/tests/typecheck/should_fail/TyAppPat_NonlinearMultiPat.stderr b/testsuite/tests/typecheck/should_fail/TyAppPat_NonlinearMultiPat.stderr
index 48aeba149e..82c78654f7 100644
--- a/testsuite/tests/typecheck/should_fail/TyAppPat_NonlinearMultiPat.stderr
+++ b/testsuite/tests/typecheck/should_fail/TyAppPat_NonlinearMultiPat.stderr
@@ -1,16 +1,16 @@
 
-TyAppPat_NonlinearMultiPat.hs:9:19: error:
+TyAppPat_NonlinearMultiPat.hs:10:19: error:
     Type variable ‘a’ is already in scope.
     Type applications in patterns must bind fresh variables, without shadowing.
 
-TyAppPat_NonlinearMultiPat.hs:10:18: error:
+TyAppPat_NonlinearMultiPat.hs:11:18: error:
     Type variable ‘a’ is already in scope.
     Type applications in patterns must bind fresh variables, without shadowing.
 
-TyAppPat_NonlinearMultiPat.hs:11:19: error:
+TyAppPat_NonlinearMultiPat.hs:12:19: error:
     Type variable ‘a’ is already in scope.
     Type applications in patterns must bind fresh variables, without shadowing.
 
-TyAppPat_NonlinearMultiPat.hs:12:18: error:
+TyAppPat_NonlinearMultiPat.hs:13:18: error:
     Type variable ‘a’ is already in scope.
     Type applications in patterns must bind fresh variables, without shadowing.
diff --git a/testsuite/tests/typecheck/should_fail/TyAppPat_NonlinearSinglePat.hs b/testsuite/tests/typecheck/should_fail/TyAppPat_NonlinearSinglePat.hs
index f80e6d448c..192dfbc8e1 100644
--- a/testsuite/tests/typecheck/should_fail/TyAppPat_NonlinearSinglePat.hs
+++ b/testsuite/tests/typecheck/should_fail/TyAppPat_NonlinearSinglePat.hs
@@ -1,6 +1,7 @@
 {-# LANGUAGE TypeApplications #-}
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE ExistentialQuantification #-}
+{-# LANGUAGE ScopedTypeVariables #-}
 
 module Main where
 
diff --git a/testsuite/tests/typecheck/should_fail/TyAppPat_NonlinearSinglePat.stderr b/testsuite/tests/typecheck/should_fail/TyAppPat_NonlinearSinglePat.stderr
index b25bfcde34..0d06da09d2 100644
--- a/testsuite/tests/typecheck/should_fail/TyAppPat_NonlinearSinglePat.stderr
+++ b/testsuite/tests/typecheck/should_fail/TyAppPat_NonlinearSinglePat.stderr
@@ -1,3 +1,3 @@
 
-TyAppPat_NonlinearSinglePat.hs:12:6: error:
+TyAppPat_NonlinearSinglePat.hs:13:6: error:
     Variable `a' would be bound multiple times by a type argument.
diff --git a/testsuite/tests/typecheck/should_fail/TyAppPat_Nonmatching.hs b/testsuite/tests/typecheck/should_fail/TyAppPat_Nonmatching.hs
index 7d6b8a47a5..4f03a4782e 100644
--- a/testsuite/tests/typecheck/should_fail/TyAppPat_Nonmatching.hs
+++ b/testsuite/tests/typecheck/should_fail/TyAppPat_Nonmatching.hs
@@ -1,6 +1,7 @@
 {-# LANGUAGE TypeApplications #-}
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE ExistentialQuantification #-}
+{-# LANGUAGE ScopedTypeVariables #-}
 
 module Main where
 
diff --git a/testsuite/tests/typecheck/should_fail/TyAppPat_Nonmatching.stderr b/testsuite/tests/typecheck/should_fail/TyAppPat_Nonmatching.stderr
index 4d70de517c..72a6e27eb8 100644
--- a/testsuite/tests/typecheck/should_fail/TyAppPat_Nonmatching.stderr
+++ b/testsuite/tests/typecheck/should_fail/TyAppPat_Nonmatching.stderr
@@ -1,11 +1,11 @@
 
-TyAppPat_Nonmatching.hs:8:6: error:
+TyAppPat_Nonmatching.hs:9:6: error:
     • Couldn't match expected type ‘a’ with actual type ‘Int’
       ‘a’ is a rigid type variable bound by
         the type signature for:
           foo :: forall a. Maybe a -> a
-        at TyAppPat_Nonmatching.hs:7:1-19
+        at TyAppPat_Nonmatching.hs:8:1-19
     • In the pattern: Just @Int x
       In an equation for ‘foo’: foo (Just @Int x) = x
     • Relevant bindings include
-        foo :: Maybe a -> a (bound at TyAppPat_Nonmatching.hs:8:1)
+        foo :: Maybe a -> a (bound at TyAppPat_Nonmatching.hs:9:1)
diff --git a/testsuite/tests/typecheck/should_fail/TyAppPat_PatternBinding.hs b/testsuite/tests/typecheck/should_fail/TyAppPat_PatternBinding.hs
index 978e611501..f7de9ab2de 100644
--- a/testsuite/tests/typecheck/should_fail/TyAppPat_PatternBinding.hs
+++ b/testsuite/tests/typecheck/should_fail/TyAppPat_PatternBinding.hs
@@ -1,6 +1,7 @@
 {-# LANGUAGE TypeApplications #-}
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE ExistentialQuantification #-}
+{-# LANGUAGE ScopedTypeVariables #-}
 
 module Main where
 
diff --git a/testsuite/tests/typecheck/should_fail/TyAppPat_PatternBinding.stderr b/testsuite/tests/typecheck/should_fail/TyAppPat_PatternBinding.stderr
index e0d18596e0..d511b93d78 100644
--- a/testsuite/tests/typecheck/should_fail/TyAppPat_PatternBinding.stderr
+++ b/testsuite/tests/typecheck/should_fail/TyAppPat_PatternBinding.stderr
@@ -1,5 +1,5 @@
 
-TyAppPat_PatternBinding.hs:8:1: error:
+TyAppPat_PatternBinding.hs:9:1: error:
     • Binding type variables is not allowed in pattern bindings
     • In the pattern: Just @a x
       In a pattern binding: Just @a x = Just (5 :: Integer)
diff --git a/testsuite/tests/typecheck/should_fail/TyAppPat_PatternBindingExistential.hs b/testsuite/tests/typecheck/should_fail/TyAppPat_PatternBindingExistential.hs
index bd888b3bac..a8692f49fe 100644
--- a/testsuite/tests/typecheck/should_fail/TyAppPat_PatternBindingExistential.hs
+++ b/testsuite/tests/typecheck/should_fail/TyAppPat_PatternBindingExistential.hs
@@ -1,6 +1,7 @@
 {-# LANGUAGE TypeApplications #-}
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE ExistentialQuantification #-}
+{-# LANGUAGE ScopedTypeVariables #-}
 
 module Main where
 
diff --git a/testsuite/tests/typecheck/should_fail/TyAppPat_PatternBindingExistential.stderr b/testsuite/tests/typecheck/should_fail/TyAppPat_PatternBindingExistential.stderr
index 9204f8016a..86f983241b 100644
--- a/testsuite/tests/typecheck/should_fail/TyAppPat_PatternBindingExistential.stderr
+++ b/testsuite/tests/typecheck/should_fail/TyAppPat_PatternBindingExistential.stderr
@@ -1,22 +1,22 @@
 
-TyAppPat_PatternBindingExistential.hs:9:1: error:
+TyAppPat_PatternBindingExistential.hs:10:1: error:
     • Binding type variables is not allowed in pattern bindings
     • In the pattern: Some @a x
       In a pattern binding: Some @a x = Some (5 :: Integer)
 
-TyAppPat_PatternBindingExistential.hs:9:9: error:
+TyAppPat_PatternBindingExistential.hs:10:9: error:
     • Couldn't match expected type ‘p’ with actual type ‘a’
       ‘a’ is a rigid type variable bound by
         a pattern with constructor: Some :: forall a. a -> Some,
         in a pattern binding
-        at TyAppPat_PatternBindingExistential.hs:9:1-9
+        at TyAppPat_PatternBindingExistential.hs:10:1-9
       ‘p’ is a rigid type variable bound by
         the inferred type of x :: p
-        at TyAppPat_PatternBindingExistential.hs:9:1-31
+        at TyAppPat_PatternBindingExistential.hs:10:1-31
     • In the pattern: Some @a x
       In a pattern binding: Some @a x = Some (5 :: Integer)
 
-TyAppPat_PatternBindingExistential.hs:12:3: error:
+TyAppPat_PatternBindingExistential.hs:13:3: error:
     • Ambiguous type variable ‘a0’ arising from a use of ‘print’
       prevents the constraint ‘(Show a0)’ from being solved.
       Probable fix: use a type annotation to specify what ‘a0’ should be.
diff --git a/testsuite/tests/typecheck/should_fail/TyAppPat_TooMany.hs b/testsuite/tests/typecheck/should_fail/TyAppPat_TooMany.hs
index 03f44f052f..d69ec335b4 100644
--- a/testsuite/tests/typecheck/should_fail/TyAppPat_TooMany.hs
+++ b/testsuite/tests/typecheck/should_fail/TyAppPat_TooMany.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE TypeApplications #-}
 module TyAppPat_TooMany where
 
 f :: Maybe Int -> Int
diff --git a/testsuite/tests/typecheck/should_fail/TyAppPat_TooMany.stderr b/testsuite/tests/typecheck/should_fail/TyAppPat_TooMany.stderr
index 87e9044919..2b5e60d49b 100644
--- a/testsuite/tests/typecheck/should_fail/TyAppPat_TooMany.stderr
+++ b/testsuite/tests/typecheck/should_fail/TyAppPat_TooMany.stderr
@@ -1,5 +1,5 @@
 
-TyAppPat_TooMany.hs:4:4: error:
+TyAppPat_TooMany.hs:6:4: error:
     • Too many type arguments in constructor pattern for ‘Just’
       Expected no more than 1; got 2
     • In the pattern: Just @Int @Bool x
diff --git a/testsuite/tests/typecheck/should_fail/all.T b/testsuite/tests/typecheck/should_fail/all.T
index 3eff08d080..c55425ae3a 100644
--- a/testsuite/tests/typecheck/should_fail/all.T
+++ b/testsuite/tests/typecheck/should_fail/all.T
@@ -593,6 +593,7 @@ test('T10709', normal, compile_fail, [''])
 test('T10709b', normal, compile_fail, [''])
 test('GivenForallLoop', normal, compile_fail, [''])
 test('T18891a', normal, compile_fail, [''])
+test('T19109', normal, compile_fail, [''])
 test('TyAppPat_ExistentialEscape', normal, compile_fail, [''])
 test('TyAppPat_MisplacedApplication', normal, compile_fail, [''])
 test('TyAppPat_NonlinearMultiAppPat', normal, compile_fail, [''])