REGEXP_FILE
  RegExpPatternImpl: <a\p{123}>
    RegExpBranchImpl: <a\p{123}>
      RegExpCharImpl: <a>
        PsiElement(CHARACTER)('a')
      RegExpPropertyImpl: <\p{>
        PsiElement(PROPERTY)('\p')
        PsiElement(LBRACE)('{')
        PsiErrorElement:Property name expected
          <empty list>
      RegExpCharImpl: <1>
        PsiElement(CHARACTER)('1')
      RegExpCharImpl: <2>
        PsiElement(CHARACTER)('2')
      RegExpCharImpl: <3>
        PsiElement(CHARACTER)('3')
      RegExpCharImpl: <}>
        PsiElement(CHARACTER)('}')