Setter is considered to be redundant in one of the following cases:

1. Setter has no body. Accessor visibility isn't changed, declaration isn't external and has no annotations.

   
     var myPropWithRedundantSetter: Int = 0
         set // redundant
   
     var myPropA: Int = 0
         private set // OK - property visibility is changed to private
   
     var myPropB: Int = 0
         external set // OK - implemented not in Kotlin (external)
   
     var myPropC: Int = 0
         @Inject set // OK - accessor is annotated
           

2. Setter body is a block with a single statement assigning the parameter to the backing field.

   
     var prop: Int = 0
         set(value) { // redundant
             field = value
         }