A virtual machine in the Rust type system

Name: A virtual machine in the Rust type system
Availability: InStock
Author: Aurel300

by Aurel300·Mar 3, 2026·2 points·0 comments

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AI Analysis

●●●BangerWizardryBig BrainRabbit Hole

Rust type system executes a compile-time VM using trait resolution and associated types.

Strengths

•Genuinely novel constraint: leverages Rust's next-gen solver to embed computation into type resolution itself.
•Well-documented with blog post explaining the mechanics; clear architectural insight into how traits execute.
•Transcends practical use case; pure demoscene-grade exploration of language capabilities.

Weaknesses

•Explicitly a POC, not a tool: author warns against using in production; niche audience (type theorists).
•Zero practical applications; exercises compiler but offers no utility beyond demonstrating language features.

Post Description

As a follow-up to a CTF challenge I wrote, I created a small proof-of-concept virtual machine embedded in the Rust type system. Trait resolution and in particular associated types are used to "execute" a program, represented as a type, to its final state. (The "execution" happens during Rust compilation.)

The VM architecture is simple: two 8-bit registers, a stack, a small number of instructions, including conditional control flow. However, other than patience and hitting the recursion limits, more useful/realistic architectures could be embedded as well.

I wrote a blog post that goes into more depth about how this was developed and how it all works: https://www.thenet.sk/blog0011