Merge pull request #8911 from dotty-staging/fix-#8896

Fix 8896: Add regression test

Author: liufengyun

tests/neg/i8896-a.scala

@@ -0,0 +1,20 @@
+import scala.language.`3.0`
+
+trait Foo[A]
+
+object Example {
+
+  given as Foo[Int] {
+  }
+
+  def foo0[A: Foo]: A => A = identity
+  def foo1[A](implicit foo: Foo[A]): A => A = identity
+  def foo2[A](using Foo[A]): A => A = identity
+
+  def test(): Unit = {
+    foo0(32) // error
+    foo1(32) // error
+    foo2(32)
+  }
+
+}

tests/neg/i8896-b.scala

@@ -0,0 +1,20 @@
+import scala.language.`3.1`
+
+trait Foo[A]
+
+object Example {
+
+  given as Foo[Int] {
+  }
+
+  def foo0[A: Foo]: A => A = identity
+  def foo1[A](implicit foo: Foo[A]): A => A = identity
+  def foo2[A](using Foo[A]): A => A = identity
+
+  def test(): Unit = {
+    foo0(32)
+    foo1(32) // error
+    foo2(32)
+  }
+
+}