Recent dev version of nbjavac-impl (e.g. nb-javac-impl-dev-20131106.064413-1.jar) passes OK on JDK7
Repeat until the classes get compiled
Discard the javac after compilation, as the tree was mangled and is no longer useful for code completion
Splitting actions that happen after checkForErrors and successful compilation. Setting errors to non-null value, when the error state is not clear. using ===