return nil
	}

	// We're looking for cases in which a pointer to this type
	// is a sync.Locker, but a value is not. This differentiates
	// embedded interfaces from embedded values.
	if types.Implements(types.NewPointer(typ), lockerType) && !types.Implements(typ, lockerType) {
		return []string{typ.String()}
	}

	// In go1.10, sync.noCopy did not implement Locker.
	// (The Unlock method was added only in CL 121876.)