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, 61 insertions, 0 deletions

diff --git a/test/files/pos/t0764b.scala b/test/files/pos/t0764b.scala
new file mode 100644
index 0000000000..6ae3c105c9
--- /dev/null
+++ b/test/files/pos/t0764b.scala
@@ -0,0 +1,61 @@
+// In all cases when calling "prepend" the receiver 'v'
+// has static type NodeAlias[A] or (equivalently) Node { type T = A }.
+// Since prepend explicitly returns the singleton type of the receiver,
+// the return type of prepend in all cases is "v.type", and so the call
+// to "new Main" can be parameterized with any of the following, in order
+// of decreasing specificity with a tie for second place:
+//
+//   new Main[v.type](v.prepend)
+//   new Main[NodeAlias[A]](v.prepend)
+//   new Main[Node { type T = A }](v.prepend)
+//   new Main(v.prepend)
+
+// the `fail` comments below denote what didn't compile before SI-8177 fixed all of them
+
+package p1 {
+  object t0764 {
+    type NodeAlias[A] = Node { type T = A }
+    trait Node { outer =>
+      type T <: Node
+      def prepend: Node { type T = outer.type } = ???
+    }
+
+    class Main1[A <: Node](v: NodeAlias[A]) {
+      private[this] def f1 = new Main1(v.prepend)                        // fail
+      private[this] def f2 = new Main1[NodeAlias[A]](v.prepend)          // fail
+      private[this] def f3 = new Main1[Node { type T = A }](v.prepend)   // fail
+      private[this] def f4 = new Main1[v.type](v.prepend)                // ok
+    }
+
+    class Main2[A <: Node](v: Node { type T = A }) {
+      private[this] def f1 = new Main2(v.prepend)                        // fail
+      private[this] def f2 = new Main2[NodeAlias[A]](v.prepend)          // fail
+      private[this] def f3 = new Main2[Node { type T = A }](v.prepend)   // fail
+      private[this] def f4 = new Main2[v.type](v.prepend)                // ok
+    }
+  }
+}
+
+package p2 {
+  object t0764 {
+    type NodeAlias[A] = Node { type T = A }
+    trait Node { outer =>
+      type T <: Node
+      def prepend: NodeAlias[outer.type] = ???
+    }
+
+    class Main1[A <: Node](v: NodeAlias[A]) {
+      private[this] def f1 = new Main1(v.prepend)                        // ok!  <<========== WOT
+      private[this] def f2 = new Main1[NodeAlias[A]](v.prepend)          // fail
+      private[this] def f3 = new Main1[Node { type T = A }](v.prepend)   // fail
+      private[this] def f4 = new Main1[v.type](v.prepend)                // ok
+    }
+
+    class Main2[A <: Node](v: Node { type T = A }) {
+      private[this] def f1 = new Main2(v.prepend)                        // fail
+      private[this] def f2 = new Main2[NodeAlias[A]](v.prepend)          // fail
+      private[this] def f3 = new Main2[Node { type T = A }](v.prepend)   // fail
+      private[this] def f4 = new Main2[v.type](v.prepend)                // ok
+    }
+  }
+}