Microsoft annoints Rust as a 'Tier 1' internal language

Microsoft has designated Rust as a Tier 1 internal language, placing it alongside C++, C#, and TypeScript in terms of support for internal development, according to Victor Ciura, a principal engineer for the Rust tooling team. Rust has already been incorporated into over 100 Microsoft project repositories and is used in various Microsoft services, including Microsoft 365 core services like Outlook, Word, Excel, OneDrive, and SharePoint.

The company recently built Oxidizer, a set of crates to build scalable services in Rust, to help refine these services. However, there is still significant work to be done to ensure seamless integration of Rust with existing C/C++ Windows code, particularly in light of the recent Windows Patch Tuesday patch deluge. Microsoft has made considerable progress in making Rust compatible with Microsoft Visual C++ (MSVC) by building rustc_codegen_utc, a custom Rust compiler code-generation backend that integrates the rustc compiler directly into MSVC's internal toolchain for Windows.

This allows Rust to build on the same platform with perfect compatibility, eliminating the need for a parallel implementation of every Windows-specific capability. Despite these efforts, Microsoft engineers will face challenges when mixing Rust and C++ code, especially in the "unsafe" territory where Rust's memory error flags do not cover C++ memory allocations.

Microsoft Azure CTO Mark Russinovich highlighted that about 70% of Windows CVEs are memory issues, emphasizing the importance of Rust's inherent memory safety features.