[grenoire]

No longer the entirety but still a sizeable chunk of it; it helps with regression detection for them. World's biggest test suite?

[jfkebwjsbx]

It is very common for compilers to be tested using client code. It is a practice that goes back decades.

Nowadays with so many open source projects and so much distributed computer power, it is even easier.

[pornel]

What makes it easy and powerful for Rust is that ~all Rust projects use Cargo as the build system and test runner, so Crater can really test every Rust project in existence, not just code samples hand-picked into compiler's test suite.

[jfkebwjsbx]

Only open source projects, which will not be the majority if Rust ends up taking up speed.