There was previously another post demonstrating a way to bypass trait bounds. That one was a bit too unreadable. Here’s my take on it. trait Super { type Assoc; } trait Sub: Super<Assoc: std::fmt::Debug> {} fn do_debug<O: Sub + ?Sized>(x: O::Assoc) { println!("{x:?}"); } // Doesn't need …

And by adding a struct NotDebug and debug(NotDebug), we actually can turn this example into an ICE.

and that's why existence of each and every type should be demonstrated /j

Maybe silly question... What's an ICE in this context?

It's an "Internal Compilation Error" (or "internal compiler error"), where the compiler itself panics.

Playground link with the ICE , for reference

Cheat-code for bypassing trait bounds!

robofinch February 20, 2026, 5:28am 3

This is actually just Rust adding support for C++-style duck-typed templates, and the long and mostly-irrelevant information contained in the ICE message is part of the experience.

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Cheat-code for bypassing trait bounds!

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