In hole fits, don't show VTA for inferred variables (#16456)

We fetch the ArgFlag for every argument by using splitForAllVarBndrs
instead of splitForAllTys in unwrapTypeVars.

3 files changed, 19 insertions, 0 deletions

diff --git a/testsuite/tests/typecheck/should_fail/T16456.hs b/testsuite/tests/typecheck/should_fail/T16456.hs
new file mode 100644
index 0000000000..4257483c75
--- /dev/null
+++ b/testsuite/tests/typecheck/should_fail/T16456.hs
@@ -0,0 +1,7 @@
+{-# LANGUAGE PolyKinds #-}
+module T16456 where
+
+data T p = MkT
+
+foo :: T Int
+foo = _
diff --git a/testsuite/tests/typecheck/should_fail/T16456.stderr b/testsuite/tests/typecheck/should_fail/T16456.stderr
new file mode 100644
index 0000000000..fbc0cc6ed5
--- /dev/null
+++ b/testsuite/tests/typecheck/should_fail/T16456.stderr
@@ -0,0 +1,11 @@
+
+T16456.hs:7:7: error:
+    • Found hole: _ :: T Int
+    • In the expression: _
+      In an equation for ‘foo’: foo = _
+    • Relevant bindings include foo :: T Int (bound at T16456.hs:7:1)
+      Valid hole fits include
+        foo :: T Int (bound at T16456.hs:7:1)
+        MkT :: forall {k} (p :: k). T p
+          with MkT @Int
+          (defined at T16456.hs:4:12)
diff --git a/testsuite/tests/typecheck/should_fail/all.T b/testsuite/tests/typecheck/should_fail/all.T
index 962febd640..9e0ba2e455 100644
--- a/testsuite/tests/typecheck/should_fail/all.T
+++ b/testsuite/tests/typecheck/should_fail/all.T
@@ -514,5 +514,6 @@ test('T16255', normal, compile_fail, [''])
 test('T16204c', normal, compile_fail, [''])
 test('T16394', normal, compile_fail, [''])
 test('T16414', normal, compile_fail, [''])
+test('T16456', normal, compile_fail, ['-fprint-explicit-foralls'])
 test('T16627', normal, compile_fail, [''])
 test('T502', normal, compile_fail, [''])