REGEXP_FILE
  RegExpPatternImpl: <[a-\w]>
    RegExpBranchImpl: <[a-\w]>
      RegExpClassImpl: <[a-\w]>
        PsiElement(CLASS_BEGIN)('[')
        RegExpCharRangeImpl: <a->
          RegExpCharImpl: <a>
            PsiElement(CHARACTER)('a')
          PsiElement(MINUS)('-')
        PsiErrorElement:'\w' not allowed as end of range
          RegExpSimpleClassImpl: <\w>
            PsiElement(CHAR_CLASS)('\w')
        PsiElement(CLASS_END)(']')