Surah Yasin
Quran describes future events in the past tense at many places. For example read the dialogue of God with Christ at the end of Sura al Maidah, from verse 116 onwards. This is a literary tool. Like we call a person doctor whose degree is in process and it the matter of time to get his degree. The man of Yasin was given the good tidings of Jannah but he will enter into it on the day of judgement. meanwhile he might be enjoying the hospitality of God.