Turing Complete Type Systems
Rust’s type system is Turing complete:
It is impossible to determine if a program written in a generally
Turing complete system will ever stop. That is, it is impossible to
write a program f that determines if a program
g, where g is written in a Turing complete
programming language, will ever halt. The Halting Problem
is in fact, an undecidable
problem.
How is any of this relevant?
Rust performs compile-time type inference. The type checker, in turn,
compiles and infers types, I would describe it as a compiler inside a
compiler. It is possible that rustc may never finish
compiling your Rust program! I lied, rustc stops after a
while, after hitting the recursion limit.
I understand that this post lacks content.
I'm Akshay, programmer and pixel-artist. I write open-source stuff. I also design fonts: scientifica, curie.
Reach out at oppili@irc.rizon.net.