Regression test for #10709.

Close #10709

testsuite/tests/typecheck/should_fail/T10709.hs

+module T10709 where
+
+import GHC.IO
+import Control.Monad
+
+x1 = replicateM 2 . mask
+x2 = (replicateM 2 . mask) undefined
+x3 = (replicateM 2 . mask) $ undefined

testsuite/tests/typecheck/should_fail/T10709.stderr

+
+T10709.hs:6:21: error:
+    • Couldn't match type ‘a4’ with ‘(forall a. IO a -> IO a) -> IO a5’
+      Expected: a4 -> IO a5
+        Actual: ((forall a. IO a -> IO a) -> IO a5) -> IO a5
+      Cannot instantiate unification variable ‘a4’
+      with a type involving polytypes: (forall a. IO a -> IO a) -> IO a5
+    • In the second argument of ‘(.)’, namely ‘mask’
+      In the expression: replicateM 2 . mask
+      In an equation for ‘x1’: x1 = replicateM 2 . mask
+    • Relevant bindings include
+        x1 :: a4 -> IO [a5] (bound at T10709.hs:6:1)
+
+T10709.hs:7:22: error:
+    • Couldn't match type ‘a2’ with ‘(forall a. IO a -> IO a) -> IO a3’
+      Expected: a2 -> IO a3
+        Actual: ((forall a. IO a -> IO a) -> IO a3) -> IO a3
+      Cannot instantiate unification variable ‘a2’
+      with a type involving polytypes: (forall a. IO a -> IO a) -> IO a3
+    • In the second argument of ‘(.)’, namely ‘mask’
+      In the expression: (replicateM 2 . mask) undefined
+      In an equation for ‘x2’: x2 = (replicateM 2 . mask) undefined
+    • Relevant bindings include x2 :: IO [a3] (bound at T10709.hs:7:1)
+
+T10709.hs:8:22: error:
+    • Couldn't match type ‘a0’ with ‘(forall a. IO a -> IO a) -> IO a1’
+      Expected: a0 -> IO a1
+        Actual: ((forall a. IO a -> IO a) -> IO a1) -> IO a1
+      Cannot instantiate unification variable ‘a0’
+      with a type involving polytypes: (forall a. IO a -> IO a) -> IO a1
+    • In the second argument of ‘(.)’, namely ‘mask’
+      In the first argument of ‘($)’, namely ‘(replicateM 2 . mask)’
+      In the expression: (replicateM 2 . mask) $ undefined
+    • Relevant bindings include x3 :: IO [a1] (bound at T10709.hs:8:1)

testsuite/tests/typecheck/should_fail/T10709b.hs

+module T10709b where
+
+import GHC.IO
+import Control.Monad
+
+x4 = (replicateM 2 . mask) (\_ -> return ())
+x5 = (replicateM 2 . mask) (\x -> undefined x)
+x6 = (replicateM 2 . mask) (id (\_ -> undefined))
+x7 = (replicateM 2 . mask) (const undefined)
+x8 = (replicateM 2 . mask) ((\x -> undefined x) :: a -> b)

testsuite/tests/typecheck/should_fail/T10709b.stderr

+
+T10709b.hs:6:22: error:
+    • Couldn't match type ‘p1’ with ‘forall a. IO a -> IO a’
+      Expected: (p1 -> IO ()) -> IO ()
+        Actual: ((forall a. IO a -> IO a) -> IO ()) -> IO ()
+      Cannot instantiate unification variable ‘p1’
+      with a type involving polytypes: forall a. IO a -> IO a
+    • In the second argument of ‘(.)’, namely ‘mask’
+      In the expression: (replicateM 2 . mask) (\ _ -> return ())
+      In an equation for ‘x4’:
+          x4 = (replicateM 2 . mask) (\ _ -> return ())
+
+T10709b.hs:7:22: error:
+    • Couldn't match type ‘t0’ with ‘forall a. IO a -> IO a’
+      Expected: (t0 -> IO a) -> IO a
+        Actual: ((forall a1. IO a1 -> IO a1) -> IO a) -> IO a
+      Cannot instantiate unification variable ‘t0’
+      with a type involving polytypes: forall a. IO a -> IO a
+    • In the second argument of ‘(.)’, namely ‘mask’
+      In the expression: (replicateM 2 . mask) (\ x -> undefined x)
+      In an equation for ‘x5’:
+          x5 = (replicateM 2 . mask) (\ x -> undefined x)
+
+T10709b.hs:8:22: error:
+    • Couldn't match type ‘p0’ with ‘forall a. IO a -> IO a’
+      Expected: (p0 -> IO a) -> IO a
+        Actual: ((forall a1. IO a1 -> IO a1) -> IO a) -> IO a
+      Cannot instantiate unification variable ‘p0’
+      with a type involving polytypes: forall a. IO a -> IO a
+    • In the second argument of ‘(.)’, namely ‘mask’
+      In the expression: (replicateM 2 . mask) (id (\ _ -> undefined))
+      In an equation for ‘x6’:
+          x6 = (replicateM 2 . mask) (id (\ _ -> undefined))
+
+T10709b.hs:9:22: error:
+    • Couldn't match type ‘b0’ with ‘forall a. IO a -> IO a’
+      Expected: (b0 -> IO a) -> IO a
+        Actual: ((forall a1. IO a1 -> IO a1) -> IO a) -> IO a
+      Cannot instantiate unification variable ‘b0’
+      with a type involving polytypes: forall a. IO a -> IO a
+    • In the second argument of ‘(.)’, namely ‘mask’
+      In the expression: (replicateM 2 . mask) (const undefined)
+      In an equation for ‘x7’:
+          x7 = (replicateM 2 . mask) (const undefined)
+
+T10709b.hs:10:22: error:
+    • Couldn't match type ‘a0’ with ‘forall a. IO a -> IO a’
+      Expected: (a0 -> IO a) -> IO a
+        Actual: ((forall a1. IO a1 -> IO a1) -> IO a) -> IO a
+      Cannot instantiate unification variable ‘a0’
+      with a type involving polytypes: forall a. IO a -> IO a
+    • In the second argument of ‘(.)’, namely ‘mask’
+      In the expression:
+        (replicateM 2 . mask) ((\ x -> undefined x) :: a -> b)
+      In an equation for ‘x8’:
+          x8 = (replicateM 2 . mask) ((\ x -> undefined x) :: a -> b)

testsuite/tests/typecheck/should_fail/all.T

@@ -584,3 +584,5 @@ test('too-many', normal, compile_fail, [''])
 test('T18640a', normal, compile_fail, [''])
 test('T18640b', normal, compile_fail, [''])
 test('T18640c', normal, compile_fail, [''])
+test('T10709', normal, compile_fail, [''])
+test('T10709b', normal, compile_fail, [''])