I don’t know if similar topics have been discussed...

# language-proposals

[Ayla]

I don’t know if similar topics have been discussed: const class and const collection
const class restricts all field types to be immutable (non-read-only), which can bring more optimization possibilities for hashcode (caching, just like string) and copy (reusing immutable fields instead of full copy), and this helps ensure multi-thread safety.

const data class A(
  val int:Int,
  var mutableField:String,//error: fields of a const class should be immutable
  val list:List<String>
)
const val instance= A(1,"",const ["1","2","3"])

const collection can ensure that the collection is immutable, which can be combined with collection literals to eliminate the copy overhead of varargs

fun simpleFunction(const list:List<String>){}
fun varargsFunction(vararg item:String){}

var str=""
const val c1=const ["",str]//error:The elements of a const collection should be immutable
const val c2=const [""]

simpleFunction(list2)
varargsFunction(c2)