UNT0014 generics problem with interfaces

[bdovaz]

Bug description

In the documentation of this rule it clearly states that if you pass an interface it will not fail and it is so, but if you do it with generics it will fail.

• Version of analyzers assembly: 1.20.0
• Analyzer rule: UNT0014
• Error (exception message, type, and callstack where applicable): 'IMyInterface' is not a Unity Component

To Reproduce

Test<IMyInterface>();

void Test<T>() where T : class
{
  gameObject.GetComponents<T>(); // Issues UNT0014
}

Expected behavior

It should not report a problem.

[sailro]

cc @jbevain

You are right. But this is the typical case of generics where we cannot use type-constraints provided directly for GetComponent<T> and where we should infer effective type based on the usage: Test<IMyInterface>. This is not what we are doing for now (for simplicity and performance).

So, for consistency, I refactored the diagnostic with the following rule:

• when we know for sure that the usage is invalid, add a diagnostic
• when we know for sure that the usage is valid, do nothing
• when we need to infer on usages (like in this case), do nothing (for now)