Kotlin Multiplatform v2.1.20-Beta1 Release Notes & Developer Guide

Kotlin v2.1.20-Beta1 delivers significant Analysis API enhancements with new symbol capabilities and performance optimizations, while advancing K2 compiler maturity through context parameters support and nested type aliases. The release includes critical debugger improvements for Native and Wasm platforms, plus numerous stability fixes addressing false positives and resolution issues across IDE and compilation workflows.

Highlights

• Analysis API: New KaSamConstructorSymbol to find constructed SAM types and isExternal property for KtPropertySymbol
• Analysis API: Added getClassLikeSymbolByClassId API and default imports retrieval capability
• Compiler: Context parameters parsing and resolution with FIR2IR support for improved language feature
• K2: Nested type aliases experimental feature with proper resolution in derived classes
• Performance: Optimized FirReferenceResolveHelper and FileStructureElement to reduce redundant resolve operations
• Debugger: Native debug improvements including DW_AT_trampoline support and better stepping through bridges
• Wasm: Fixed code generation for externals with backquoted identifiers and incremental compilation issues