stored to '*' during its initialization is never read

NSMutableArray *datesArray = [[NSMutableArray alloc]init]; 
 datesArray = [_onDemandDictionary objectForKey:key];

出现了

stored to 'datesArray' during its initialization is never read

改成

NSMutableArray *datesArray = nil; 
 datesArray = [_onDemandDictionary objectForKey:key];