> **PR stack (1 of 3)**
> 1. **#24739 (this PR)**
> 2. #24742
> 3. #24712
>
> Review and merge in this order.
The `oxc_ecmascript` crate currently compiles constant evaluation and side-effect analysis for every consumer, even when a consumer only needs the small shared ECMAScript value primitives. This makes optional analysis code and its dependencies part of unrelated builds.
This introduces two explicit features:
- `side_effects` enables side-effect analysis and its RegExp support.
- `constant_evaluation` enables constant evaluation and implies `side_effects`, because side-effect analysis uses constant folding for several purity decisions.
`ConstantValue`, `ValueType`, and `DetermineValueType` move to feature-independent root modules so `GlobalContext` remains available without either analysis feature. Existing paths through `constant_evaluation` remain re-exported when that feature is enabled.
This is a prerequisite for #24742, which exposes engine targets to side-effect analysis without making compatibility data part of every `oxc_ecmascript` consumer.
This is a breaking Cargo feature change for direct consumers of `oxc_ecmascript`: code using side-effect analysis or constant evaluation must enable the corresponding feature.
Verified locally with the no-feature, `side_effects`, and `constant_evaluation` configurations, crate tests, dependent linter and minifier tests, rustdoc with warnings denied, and `just ready`. The release oxlint binary on this commit is 13,350,096 bytes.
Implemented with AI assistance (OpenAI Codex and Claude). The contributor remains responsible for reviewing, understanding, and maintaining these changes.
Dunqing