Fix #1568 - avoid transforming error trees

If a tree has type error, subtrees may not have an assigned type.
Therefore we should avoid transforming such trees.

1 files changed, 3 insertions, 0 deletions

diff --git a/tests/neg/i1568.scala b/tests/neg/i1568.scala
new file mode 100644
index 000000000..a260c530b
--- /dev/null
+++ b/tests/neg/i1568.scala
@@ -0,0 +1,3 @@
+object Test {
+  inline def foo(n: Int) = foo(n) // error: cyclic reference
+}