Enabled variance checking

Variance checking is now run as part of type-checking.

Fixed tests that exhibited variance errors. Added tests where some classes of
variance errors should be detected.

1 files changed, 3 insertions, 0 deletions

diff --git a/tests/pos/variances.scala b/tests/pos/variances.scala
new file mode 100644
index 000000000..db858fd5d
--- /dev/null
+++ b/tests/pos/variances.scala
@@ -0,0 +1,3 @@
+trait C[+T <: C[T, U], -U <: C[T, U]] {
+
+}