Fix checkNonCyclic.

Need to also look info refined types.
Need to handle case where we hit a NoCompleter again.

Fixes #974 and makes MutableSortedSetFactory in stdlib compile.

2 files changed, 10 insertions, 0 deletions

diff --git a/tests/neg/i974.scala b/tests/neg/i974.scala
new file mode 100644
index 000000000..89db4b2d9
--- /dev/null
+++ b/tests/neg/i974.scala
@@ -0,0 +1,8 @@
+trait Foo[T <: Bar[T]#Elem] // error: illegal cyclic reference
+trait Bar[T] {
+  type Elem = T
+}
+trait Foo2[T <: Bar2[T]#Elem] // error: illegal cyclic reference
+trait Bar2[T] {
+  type Elem = T
+}
diff --git a/tests/pos/i974.scala b/tests/pos/i974.scala
new file mode 100644
index 000000000..4c7c15e8d
--- /dev/null
+++ b/tests/pos/i974.scala
@@ -0,0 +1,2 @@
+class Foo[A]
+class Bar[CC[X] <: Foo[CC[X]]]