REGEXP_FILE
  RegExpPatternImpl: <a[b-]>
    RegExpBranchImpl: <a[b-]>
      RegExpCharImpl: <a>
        PsiElement(CHARACTER)('a')
      RegExpClassImpl: <[b-]>
        PsiElement(CLASS_BEGIN)('[')
        RegExpCharImpl: <b>
          PsiElement(CHARACTER)('b')
        RegExpCharImpl: <->
          PsiElement(MINUS)('-')
        PsiElement(CLASS_END)(']')