REGEXP_FILE
  RegExpPatternImpl: <[\p{nothing}]>
    RegExpBranchImpl: <[\p{nothing}]>
      RegExpClassImpl: <[\p{nothing}]>
        PsiElement(CLASS_BEGIN)('[')
        RegExpPropertyImpl: <\p{nothing}>
          PsiElement(PROPERTY)('\p')
          PsiElement(LBRACE)('{')
          PsiElement(NAME)('nothing')
          PsiElement(RBRACE)('}')
        PsiElement(CLASS_END)(']')