SI-8177 refine embeddedSymbols

We look for any prefix that has a refinement class for a type symbol.
This includes ThisTypes, which were not considered before.

pos/t8177g.scala, neg/t0764*scala now compile, as they should

Additional test cases contributed by Jason & Paul.

1 files changed, 9 insertions, 0 deletions

diff --git a/test/files/pos/t8177a.scala b/test/files/pos/t8177a.scala
new file mode 100644
index 0000000000..7e2cfb386c
--- /dev/null
+++ b/test/files/pos/t8177a.scala
@@ -0,0 +1,9 @@
+// exercise coevolveSym
+trait Thing { type A; var p: A = _ }
+class AA[T](final val x: Thing { type A = T }) {
+  def foo: x.A = ???
+}
+
+class B extends AA[Int](null) {
+  override def foo: B.this.x.A = super.foo
+}