REGEXP_FILE
  RegExpPatternImpl: <(a*)+>
    RegExpBranchImpl: <(a*)+>
      RegExpClosureImpl: <(a*)+>
        RegExpGroupImpl: <(a*)>
          PsiElement(GROUP_BEGIN)('(')
          RegExpPatternImpl: <a*>
            RegExpBranchImpl: <a*>
              RegExpClosureImpl: <a*>
                RegExpCharImpl: <a>
                  PsiElement(CHARACTER)('a')
                RegExpQuantifierImpl: <*>
                  PsiElement(STAR)('*')
          PsiElement(GROUP_END)(')')
        RegExpQuantifierImpl: <+>
          PsiElement(PLUS)('+')