From the Rust Media guide, under "Uses that do not require explicit approval": * Stating accurately that software is written in the Rust programming language,

From the Rust Media guide, under "Uses that do not require explicit approval": * Stating accurately that software is written in the Rust programming language, that it is compatible with the Rust programming language, or that it contains the Rust programming language, is allowed. In those cases, you may use the Rust trademarks to indicate this, without prior approval. This is true both for non-commercial and commercial uses. I would call a compiler that compiles Rust, but does not name itself "rustc" falling under that explicit approval. (Full disclosure: I'm part of the Rust community and core team and often handle trademark decisions)