@Nullable
  static GrExpression findExpr(IntroduceParameterInfo info) {
    final GrStatement[] statements = info.getStatements();
    if (statements.length != 1) return null;
    return GrIntroduceHandlerBase.findExpression(statements[0]);
  }
@Nullable
  static GrExpression findExpr(IntroduceParameterInfo info)