Ruric Thar, the Unbowed

• WOTC Official Reminder Textofficial rules
  Vigilance — Attacking doesn't cause this creature to tap.

• WWizards of the Coast2018-03-16
  Official Ruling
  Ruric Thar's triggered ability triggers whenever any player casts a noncreature spell, including you.
• WWizards of the Coast2018-03-16
  Official Ruling
  Ruric Thar's triggered ability resolves before the spell that caused it to trigger. The ability will resolve even if that spell is countered.
• WWizards of the Coast2018-03-16
  Official Ruling
  If Ruric Thar can't attack for any reason (such as being tapped or having come under that player's control that turn), then it doesn't attack. If there's a cost associated with having a creature attack, the player isn't forced to pay that cost, so Ruric Thar doesn't have to attack in that case either.

Rulings via Scryfall