[PATCH] [YAML] Recover gracefully when deserializing invalid YAML input.

[kledzik at apple.com]

  LGTM


================
Comment at: include/llvm/Support/YAMLTraits.h:960
@@ -960,1 +959,3 @@
+  if (!yin.setCurrentDocument())
+    return yin;
   yamlize(yin, docMap, true);
----------------
Wouldn't this whole body be simpler as:

  if (yin.setCurrentDocument())
    yamlize(yin, docMap, true);
  return yin;


http://llvm-reviews.chandlerc.com/D1236