REGEXP_FILE
  RegExpPatternImpl: <a{1,foo}>
    RegExpBranchImpl: <a{1,foo}>
      RegExpClosureImpl: <a{1,>
        RegExpCharImpl: <a>
          PsiElement(CHARACTER)('a')
        RegExpQuantifierImpl: <{1,>
          PsiElement(LBRACE)('{')
          RegExpNumberImpl: <1>
            PsiElement(NUMBER)('1')
          PsiElement(COMMA)(',')
          PsiErrorElement:'}' or number expected
            <empty list>
      RegExpCharImpl: <f>
        PsiElement(CHARACTER)('f')
      RegExpCharImpl: <o>
        PsiElement(CHARACTER)('o')
      RegExpCharImpl: <o>
        PsiElement(CHARACTER)('o')
      RegExpCharImpl: <}>
        PsiElement(CHARACTER)('}')