laravel/framework — pull request #5667 by lucasmichot (2014-09-05 18:45:11+00:00)
Title: [4.2] Remove useless negated is_null

The origin of this PR comes from 7dad0db1bded77ef1a4ec0769355aadea61473c2.
In many cases, a negated `! is_null` check is done, as a single `is_null` check could be sufficient and more performant.