Cycle defense.

Notice when a typeref's info creates an obvious cycle, so we can see an
error instead of a stack overflow. Closes SI-5093, review by moors.

3 files changed, 17 insertions, 1 deletions

diff --git a/test/files/neg/t2918.check b/test/files/neg/t2918.check
index e67f24ec57..263beab518 100644
--- a/test/files/neg/t2918.check
+++ b/test/files/neg/t2918.check
@@ -1,7 +1,10 @@
+t2918.scala:2: error: illegal cyclic reference involving type A
+  def g[X, A[X] <: A[X]](x: A[X]) = x 
+                                    ^
 t2918.scala:2: error: cyclic aliasing or subtyping involving type A
   def g[X, A[X] <: A[X]](x: A[X]) = x 
            ^
 t2918.scala:2: error: A does not take type parameters
   def g[X, A[X] <: A[X]](x: A[X]) = x 
                             ^
-two errors found
+three errors found
diff --git a/test/files/neg/t5093.check b/test/files/neg/t5093.check
new file mode 100644
index 0000000000..daba460011
--- /dev/null
+++ b/test/files/neg/t5093.check
@@ -0,0 +1,10 @@
+t5093.scala:2: error: illegal cyclic reference involving type C
+  def f[C[X] <: C[X]](l: C[_]) = l.x
+                                 ^
+t5093.scala:2: error: cyclic aliasing or subtyping involving type C
+  def f[C[X] <: C[X]](l: C[_]) = l.x
+        ^
+t5093.scala:2: error: C does not take type parameters
+  def f[C[X] <: C[X]](l: C[_]) = l.x
+                         ^
+three errors found
diff --git a/test/files/neg/t5093.scala b/test/files/neg/t5093.scala
new file mode 100644
index 0000000000..9cde364dee
--- /dev/null
+++ b/test/files/neg/t5093.scala
@@ -0,0 +1,3 @@
+class T {
+  def f[C[X] <: C[X]](l: C[_]) = l.x
+}