php-anon-fn.php

<?php
// short syntax available in php 7.4 and up

Project::with('user')
  
    // regular anonymous php function expression
    ->whereHas('user', function($query) {
        $query->where('role', 'admin'); 
    })
  
    // short anonymous php function expression ("fat arrow" fn)
    ->whereHas('user', fn($query) => $query->where('role', 'admin'))
  
    ->get()
;