Merge pull request #9742 from joroKr21/t8493

Fix scala/bug#8493 - add regression test

test/files/pos/t8493.scala

@@ -0,0 +1,25 @@
+object Test {
+  trait Foo {
+    def foo: this.type
+  }
+
+  case class Impl() extends Foo {
+    def foo = ???
+    def bar: Unit = ()
+  }
+
+  object Foo {
+    def foo(f: Foo): f.type = f.foo
+  }
+
+  def work(f: Impl): Unit =
+    Foo.foo(f).bar
+
+  def bug(f: Int => Impl): Unit =
+    Foo.foo(f(1)).bar
+
+  def workaround(f: Int => Impl): Unit = {
+    val tmp = f(1)
+    Foo.foo(tmp).bar
+  }
+}