NoCanIgnoreReturnValueOnClasses
@CanIgnoreReturnValue should not be applied to classes as it almost always overmatches (as it applies to constructors and all methods), and the CIRVness isn't conferred to its subclasses.
Suppression
Suppress false positives by adding the suppression annotation @SuppressWarnings("NoCanIgnoreReturnValueOnClasses") to the enclosing element.