E0277 — Trait Not Satisfied

What causes this error

A function, struct, or trait bound requires a type to implement a specific trait, but the type does not. This is common with Display, Debug, Clone, and other standard traits. Generic functions often require trait bounds that your type does not satisfy.

How to fix it

Implement the required trait for your type using #[derive(...)] or a manual impl block. Check if the trait can be derived automatically. Use a wrapper type that implements the trait.

fn print_it(x: impl std::fmt::Display) {}
struct Foo;
print_it(Foo);