REGEXP_FILE
  RegExpPatternImpl: <ab*c>
    RegExpBranchImpl: <ab*c>
      RegExpCharImpl: <a>
        PsiElement(CHARACTER)('a')
      RegExpClosureImpl: <b*>
        RegExpCharImpl: <b>
          PsiElement(CHARACTER)('b')
        RegExpQuantifierImpl: <*>
          PsiElement(STAR)('*')
      RegExpCharImpl: <c>
        PsiElement(CHARACTER)('c')