# rust-lang/rust · RepoSense Release & Migration Intelligence

> library: fix missing symbol `wcslen` on UEFI and embedded. Drop-in upgrade. Migration: None.

## Metadata
- **Repository URL**: https://github.com/rust-lang/rust
- **Primary Package**: `@rust-lang/rust` (NPM)
- **Categories**: `LANGUAGE`
- **Latest Version**: `v1.99.1`
- **Semantic Status**: `COMPATIBLE`
- **Bundle Size Impact (unavailable)**: `Size Unavailable`
- **Atom Ingestion Feed**: https://github.com/rust-lang/rust/releases.atom

## The Human Context (Plain-English Pitch)
@rust-lang/rust is an open-source library and developer tool in the rust-lang/rust ecosystem. It saves developers from writing repetitive low-level boilerplate from scratch by providing a battle-tested, open-source implementation ready for production.

## Stage 1 Executive Summary ([Core Change] + [Required Action] + [Migration Effort])
library: fix missing symbol `wcslen` on UEFI and embedded. Drop-in upgrade. Migration: None.

## Breaking Changes & Required Actions
- library: fix missing symbol `wcslen` on UEFI and embedded targets
- rustc: fix miscompilation of FFI `bool` return values on x86_64
- rust-lld: add the rpath for `libLLVM` on macOS

## Migration Snippet
```ts
npm install @rust-lang/rust@1.99.1
```

## Ecosystem Compatibility Matrix & Graph Warnings
- **TypeScript 5.x** [`COMPATIBLE`]: Ships standard TypeScript declaration files without type regressions.

## Zero-Noise Release Timeline
- **v1.99.1** (2026-10-16) [COMPATIBLE]: library: fix missing symbol `wcslen` on UEFI and embedded. Drop-in upgrade. Migration: None.

## Upgrade & Migration Q&A (GEO Direct Answers)
### Is rust-lang/rust v1.99.1 safe to upgrade in production?
rust-lang/rust v1.99.1 is classified as COMPATIBLE (PATCH release). library: fix missing symbol `wcslen` on UEFI and embedded. Drop-in upgrade. Migration: None.

### What breaking changes or compatibility risks exist in rust-lang/rust v1.99.1?
No breaking API changes or peer dependency conflicts are recorded for rust-lang/rust v1.99.1 in the RepoSense compatibility graph.

### What is the bundle size impact of @rust-lang/rust v1.99.1?
Measured bundle size telemetry is currently unavailable for @rust-lang/rust v1.99.1; verify build output locally before deploying.

### How do I upgrade @rust-lang/rust to v1.99.1?
Upgrade @rust-lang/rust to v1.99.1 by running "npm install @rust-lang/rust@1.99.1" and applying the migration steps: npm install @rust-lang/rust@1.99.1