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