MutableMap.toMap() return mutableMap if size >1. How I should get immutable map from mutable map?

# getting-started

[Konstantin Petrukhnov]

MutableMap.toMap() return mutableMap if size >1. How I should get immutable map from mutable map?

[adam-mcneilly]

Can you post the code you're using? I tried this, and I get an error that it cannot resolve `put`:

val mutableMap = mutableMapOf(1 to 1, 2 to 2)
val immutableMap = mutableMap.toMap()
immutableMap.put(3, 3)

[Andreas Sinz]

There are no immutable collections in stdlib, just read-only views to mutable collections

[Konstantin Petrukhnov]

@adam-mcneilly I'm not trying to modify it. But I got error:
instances of kotlin.Error, kotlin.RuntimeException and subclasses aren't propagated from Kotlin to Objective-C/Swift.
Other exceptions can be propagated as NSError if method has or inherits @Throws annotation.
Uncaught Kotlin exception: konan.worker.InvalidMutabilityException: mutation attempt of frozen {a=[E,S,D], b=[C,F,G]} (hash is 0x45f9e1aa)
at 3 0x00000001027ec278 kfun:kotlin.collections.HashMap.<get-entries>()kotlin.collections.MutableSet<kotlin.collections.MutableMap.MutableEntry<#GENERIC,#GENERIC>> + 1172
at 4 0x000000010278817c kfun:a.b.c.MyService.getStringValue$M(kotlin.Long)kotlin.String? + 424

And it point to line, where I'm trying to get value from map.

[Konstantin Petrukhnov]

And from kotlin sources:
/**
* Returns a new read-only map containing all key-value pairs from the original map.
*
* The returned map preserves the entry iteration order of the original map.
*/
@SinceKotlin("1.1")
public fun <K, V> Map<out K, V>.toMap(): Map<K, V> = when (size) {
0 -> emptyMap()
1 -> toSingletonMap()
else -> toMutableMap()
}

[Andreas Sinz]

thats something for #kotlin-native