@Nullable
  private ValueConstraint getLiteralConstraint(@Nullable LighterASTNode expr) {
    if (expr != null && expr.getTokenType() == LITERAL_EXPRESSION) {
      return getLiteralConstraint(myTree.getChildren(expr).get(0).getTokenType());
    }
    return null;
  }
@Nullable
  private ValueConstraint getLiteralConstraint(@Nullable LighterASTNode expr)