REGEXP_FILE
  RegExpPatternImpl: <([\^])>
    RegExpBranchImpl: <([\^])>
      RegExpGroupImpl: <([\^])>
        PsiElement(GROUP_BEGIN)('(')
        RegExpPatternImpl: <[\^]>
          RegExpBranchImpl: <[\^]>
            RegExpClassImpl: <[\^]>
              PsiElement(CLASS_BEGIN)('[')
              RegExpCharImpl: <\^>
                PsiElement(ESC_CHARACTER)('\^')
              PsiElement(CLASS_END)(']')
        PsiElement(GROUP_END)(')')