Introduce recursive types

Map self-references in refinements to recursive types. This
commit does this for refinement types appearing in source.
We still have to do it for unpickled refinements.

Test apply-equiv got moved to pending because it simulates
the old higher-kinded type encoding in source, which relies
on the old representation in terms of self-referential refinement
types. The plan is not to adapt this encoding to the new
representation, but to replace it with a different encoding
that makes critical use of the added power of recursive types.

Use recursive types also when unpickling from Scala 2.x.

Add mapInfo method to Denotations.

1 files changed, 14 insertions, 0 deletions

diff --git a/tests/pending/pos/apply-equiv.scala b/tests/pending/pos/apply-equiv.scala
new file mode 100644
index 000000000..f53b8b5ab
--- /dev/null
+++ b/tests/pending/pos/apply-equiv.scala
@@ -0,0 +1,14 @@
+class Test {
+
+  class Lambda { type Arg; type Apply }
+
+  type T1 = (Lambda { type Arg = Int } { type Apply = List[Arg] }) # Apply
+  type T2 = List[Int]
+
+  var x: T1 = _
+  var y: T2 = _
+
+  x = y
+  y = x
+
+}