FIX: Jumping to a post that doesn't exist should jump to closest

app/assets/javascripts/discourse/lib/url.js.es6

@@ -274,18 +274,17 @@ const DiscourseURL = Ember.Object.extend({
 
         if (newMatches[3]) { opts.nearPost = newMatches[3]; }
         if (path.match(/last$/)) { opts.nearPost = topicController.get('model.highest_post_number'); }
-        const closest = opts.nearPost || 1;
 
         opts.cancelSummary = true;
 
         postStream.refresh(opts).then(() => {
+          const closest = postStream.closestPostNumberFor(opts.nearPost || 1);
           topicController.setProperties({
             'model.currentPost': closest,
             enteredAt: new Date().getTime().toString()
           });
 
           this.appEvents.trigger('post:highlight', closest);
-        }).then(() => {
           const jumpOpts = {
             skipIfOnScreen: routeOpts.skipIfOnScreen
           };