REGEXP_FILE
  RegExpPatternImpl: <[a&&]>
    RegExpBranchImpl: <[a&&]>
      RegExpClassImpl: <[a&&]>
        PsiElement(CLASS_BEGIN)('[')
        RegExpIntersectionImpl: <a&&>
          RegExpCharImpl: <a>
            PsiElement(CHARACTER)('a')
          PsiElement(ANDAND)('&&')
        PsiElement(CLASS_END)(']')