Kotlin language features and proposals

Edit pageLast modified: 18 March 2025

JetBrains evolves the Kotlin language according to the Kotlin language evolution principles, guided by pragmatic design.

note

Language feature proposals are listed from Kotlin 1.7.0.

See the explanation of language feature statuses in the Kotlin evolution principles documentation.

Exploration and design

Kotlin statics and static extensions

Exploration and design

Collection literals

  • KEEP proposal: Not defined

  • YouTrack issue: KT-43871

Exploration and design

Union types for errors and exceptions

  • KEEP proposal: Not defined

  • YouTrack issue: KT-68296

Exploration and design

Name-based destructuring

  • KEEP proposal: Not defined

  • YouTrack issue: KT-19627

Exploration and design

Support immutability

KEEP discussion

KMP Kotlin-to-Java direct actualization

KEEP discussion

kotlin.time.Instant

KEEP discussion

Common Atomics and Atomic Arrays

KEEP discussion

Improvements to annotation use-site targets on properties

KEEP discussion

Nested (non-capturing) type aliases

KEEP discussion

Streamline KDoc ambiguity links

KEEP discussion

Resolution of links to extensions in KDoc

KEEP discussion

Uuid

KEEP discussion

Improve resolution using expected type

KEEP discussion

Expose boxed inline value classes in JVM

KEEP discussion

Explicit backing fields: both public and private type for the same property

KEEP discussion

Context parameters: support for context-dependent declarations

KEEP discussion

Java synthetic property references

In preview

Guard conditions in when-with-subject

Stable

Stabilized @SubclassOptInRequired

In preview

Multidollar interpolation: improved handling of $ in string literals

In preview

Non-local break and continue

Stable

Enum.entries: performant replacement of the Enum.values()

Stable

Data objects

Stable

RangeUntil operator ..<

Stable

Definitely non-nullable types

Revoked

Context receivers