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Kotlin 2.5.0-Beta1: Separate Compilation to Resolve Inconsistencies Between IDE and Compiler Published on 28 September 2026 by Christ-loisele (2 min read)
The Kotlin 2.5.0 beta version introduces an experimental approach to separate compilation for Kotlin Multiplatform, aiming to eliminate discrepancies between IntelliJ IDEA IDE analysis and the compiler. This feature, disabled by default, could improve the reliability of multiplatform projects by aligning behaviors and more accurately detecting problematic calls.
A Recurring Issue in Kotlin Multiplatform
The current Kotlin Multiplatform (KMP) compilation system generates unexpected behaviors, particularly disagreements between IntelliJ IDEA IDE analysis and the compiler. According to JetBrains, the IDE is often stricter than the compiler: it flags unresolved references that the compiler accepts, creating a source of confusion for developers. For example, code in a source set common (commonTest) may accidentally call platform-specific code, breaking design assumptions. These inconsistencies complicate development and increase the risk of production errors.
Separate compilation ensures compilation results are consistent with IDE analysis, eliminating a major source of frustration for Kotlin Multiplatform developers
Illustration: Lawing Tech Separate Compilation: An Experimental Solution
Kotlin 2.5.0-Beta1 introduces an experimental separate compilation feature to address these issues. According to Aleksey Zamulla, an engineer at JetBrains, this approach makes compilation results consistent with IDE analysis , avoiding behavioral gaps. It also helps better identify problematic calls from common source sets to platform-specific dependencies. A notable advancement is the implementation of incremental compilation for common source sets , reducing build times. However, this feature remains disabled by default and must be manually enabled via a Gradle option.
Compiler Alignment with IDE Expectations
JetBrains emphasizes that the compiler and IDE do not always agree on aspects such as overload resolution or type inference. Separate compilation corrects this divergence by making the compiler stricter , in line with IDE expectations during the compilation of common source sets . This should limit late-stage compilation errors and improve project predictability. The expect/actual declarations, used to explicitly link platform-specific implementations to common declarations, also benefit from this stabilization.
What This Changes Here
For companies and government agencies in Benin and West Africa developing multiplatform applications with Kotlin Multiplatform, this update could reduce bugs related to compilation inconsistencies , particularly in critical projects such as banking systems or government platforms. Teams using Gradle will need to manually configure this experimental option, but it could accelerate development cycles and improve code quality. Local developers working on commonMain solutions will also benefit from better detection of problematic calls, reducing regression risks.
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