REGEXP_FILE
  RegExpPatternImpl: <[&&]>
    RegExpBranchImpl: <[&&]>
      RegExpClassImpl: <[&&]>
        PsiElement(CLASS_BEGIN)('[')
        RegExpIntersectionImpl: <&&>
          PsiElement(ANDAND)('&&')
          PsiErrorElement:Character class expected
            <empty list>
        PsiElement(CLASS_END)(']')