GitHub Copilot is now written entirely in Rust, with AI agents doing most of the porting work.
The migration cost about $120,000 in AI token usage plus about three weeks of a developer's time.
The effort updated the runtime module-by-module until the job was completed, spanning over 135 releases across a 14.5-week time period.
430,000 lines of TypeScript were converted into 800,000 lines of Rust.
$120k to port 430,000 loc seems quite expensive. That's dozens of cents per line of code, and equivalent to the all-in cost of a senior engineer in London for a year.
Especially expensive when you take into account the amount of that code which must have been boilerplate & meta-code in nature, meaning it should have been straightforward to move.
Porting this to rust would be a multiyear, multiengineer project normally. And in fact you would almost certainly never do it, because it would be too expensive and you'd have to take engineers off of work building new features for ages.
antonmks · · focus · HN ↗
OtherShrezzing · · focus · HN ↗
Especially expensive when you take into account the amount of that code which must have been boilerplate & meta-code in nature, meaning it should have been straightforward to move.
efficax · · focus · HN ↗