Can we expand this ticket to all other cases with the same problem?

• Strings like 'TheClass::theMethod' can be replaced with either [ TheClass::class, 'theMethod' ] or TheClass::class . '::theMethod', depending on the context, e.g. in method_exists or is_callable.
• array_map and many other PHP functions accept callbacks. If a string like above is detected, it might be worth replacing it.
• new ReflectionMethod( TheClass::class, … )
• PHPUnit:
  • $this->createMock( TheClass::class ), as well as getMock and getMockBuilder, as long as they exist.
  • setExpectedException
  • assertInstanceOf, assertContainsOnlyInstancesOf, and isInstanceOf
• $maintClass = TheClass::class in maintenance scripts.
• Assert::parameterType( TheClass::class ) and a few more from our very own assert component.

There is also stuff like 'class' => TheClass:class in API and ResouceLoader module registration and such, but it's probably super-hard to detect these in an automatic sniff.