Warn about catching non-local returns.

Almost every time someone is shooting themself in the foot
by catching a non-local return, it is apparent from the
structure of the AST that they are doing so.  Warn them.

1 files changed, 9 insertions, 0 deletions

diff --git a/test/files/neg/nonlocal-warning.check b/test/files/neg/nonlocal-warning.check
new file mode 100644
index 0000000000..efb3efaaa2
--- /dev/null
+++ b/test/files/neg/nonlocal-warning.check
@@ -0,0 +1,9 @@
+nonlocal-warning.scala:4: warning: This catches all Throwables. If this is really intended, use `case x: Throwable` to clear this warning.
+    catch { case x => 11 }
+                 ^
+nonlocal-warning.scala:2: warning: catch block may intercept non-local return from method foo
+  def foo(l: List[Int]): Int = {
+                               ^
+error: No warnings can be incurred under -Xfatal-warnings.
+two warnings found
+one error found