Microsoft annoints Rust as a 'Tier 1' internal language

When Microsoft's developers and engineers sit down to code, they can now choose to work in Rust, which Redmond has added to its list of canonical languages.

“Rust now is a Tier One language at Microsoft, and that just means that it sits among C++, C# and TypeScript as the best supported languages for internal development in the company,” explained Victor Ciura, Microsoft principal engineer for the Rust tooling team, during a keynote talk today at this year’s annual RustConf, being held this week in Montréal.

Ciura said Microsoft has “paved a path” of tools and processes that support local Rust development across the entire software development lifecycle.

Rust is no stranger at Microsoft and is already present in over 100 Microsoft project repositories.

The company has built Oxidizer, a set of crates to build scalable services in Rust, which have been used to build and refine the Microsoft 365 (M365) core services such as Outlook, Word, Excel, OneDrive, and SharePoint.

The Copilot tech stack also owes quite a bit to Rust.

But the really messy work still lies ahead.

Given the recent Windows Patch Tuesday patch deluge, no doubt one of the largest uses for Rust will be shoring up leaky C/C++ Windows code.

This is the work Rust was made for.

Mozilla developer Graydon Hoare created Rust as a side project in 2006 chiefly as a high-performance language that, unlike C and C++, guarded against memory bugs.

Rewriting programs in Rust to improve performance and minimize bugs has since become a common chore for project leaders, who have Rustified everything from databases to package managers, often with the help of AI.

New digs Redmond has already done considerable work making Rust comfy on Microsoft Visual C++ (MSVC), its native platform for compiling Windows binaries.

Notably, company engineers built rustc_codegen_utc, a custom Rust compiler code-generation backend that wires the rustc compiler directly into MSVC’s internal toolchain for Windows.

“Connecting rustc to that backend lets Rust build on the same platform investment, with perfect compatibility out of the box, rather than requiring a parallel implementation of every Windows-specific capability,” wrote Ciura in a blog post that details Redmond's rusty efforts.