[ibdknox]

Huh, does MIRI mean that rust is actually doing some form of partial evaluation during compilation? What's the best way to learn more about that?

[steveklabnik]

MIRI is short for "MIR Interpreter"; it can run basically any Rust code. But, in the compiler itself, its interface is restricted a bit; we haven't fully defined what "const fn" will be.

https://github.com/solson/miri is probably the best place to start poking around :)