code: @Override
    public void report(Diagnostic<? extends JavaFileObject> diagnostic) {
      if (diagnostic.getKind() != Kind.ERROR)
        return;
      report(new CompilerReport(diagnostic));
    }
docs: Reports a compiler diagnostic. This diagnostic manager only
  reports errors from the underlying compiler tool invocation,
  which calls this method; anything other than an error is
  ignored. This prevents the annotation processor from picking up
  irrelevant warnings pertaining to generated code.