In the Build setting, I searched for unused. I saw the setting (3 columns in project, 4 in Targets)
Resolve, myApp (in target only), myApp and iOS Default
I wanted the alerts , so I set all to Yes except for the last column which is set to No and that I cannot change.
That was my ScreenShot.
the reading your answer, I realized that I was checking if it was working with Instance Var and it was not working but I just check inside a func and it work.
I guess it must be the normal behaviour for instance var to not give the alert.
Thank you Claude31, I think it's not the first time you help me !