@Nullable
  static GrVariable findVar(IntroduceParameterInfo info) {
    GrVariable variable = info.getVar();
    if (variable != null) return variable;

    final GrStatement[] statements = info.getStatements();
    if (statements.length != 1) return null;
    return GrIntroduceHandlerBase.findVariable(statements[0]);
  }
@Nullable
  static GrVariable findVar(IntroduceParameterInfo info)