Argus: An Interactive Debugger for Demystifying Complex Rust Trait Errors

Rust's powerful type system is renowned, but complex type errors can be frustrating for developers. This article introduces Argus, an interactive debugger that visualizes the Rust trait inference tree in a graphical interface, helping developers understand complex trait errors step by step. Argus offers both bottom-up and top-down views, along with interactive expansion of long types and paths, significantly improving error localization efficiency. A user study showed a 3.3x speedup in locating trait errors using Argus. Argus is available as a VSCode extension and the source code is open-sourced.