code: public void pushLoop(VariableScope el, String labelName) {
          pushVariableScope(el);
          continueLabel = new Label();
          breakLabel = new Label();
          if (labelName != null) {
              initLoopLabels(labelName);
          }
      }
docs: Should be called when descending into a loop that defines
  also a scope. Calls pushVariableScope and prepares labels
  for a loop structure. Creates a element for the state stack
  so pop has to be called later, TODO: @Deprecate