REGEXP_FILE
  RegExpPatternImpl: <[[:blank:]]>
    RegExpBranchImpl: <[[:blank:]]>
      RegExpClassImpl: <[[:blank:]]>
        PsiElement(CLASS_BEGIN)('[')
        RegExpPosixBracketExpressionImpl: <[:blank:]>
          PsiElement(BRACKET_EXPRESSION_BEGIN)('[:')
          PsiElement(NAME)('blank')
          PsiElement(BRACKET_EXPRESSION_END)(':]')
        PsiElement(CLASS_END)(']')