Rust Error E0754: Non-ASCII Identifier in Invalid Context

Understanding Rust Error E0754

Rust Error E0754 occurs when a non-ASCII (non-American Standard Code for Information Interchange) identifier is used in an invalid context. An identifier is a sequence of characters that signifies a user-defined variable, function, or other program element, and it must follow certain lexical rules.

Erroneous code examples

mod řųśť; // error!

#[no_mangle]
fn řųśť() {} // error!

fn main() {}

Possible Solutions

To resolve Rust Error E0754, you can use non-ASCII identifiers in specific contexts only, such as inlined module names or with a #[path] attribute. The following example shows proper usage:

mod řųśť { // ok!
    const IS_GREAT: bool = true;
}

fn main() {}

In this case, the non-ASCII identifier 'řųśť' can be used as a module name since it is inlined within the code. If you need to use a non-ASCII identifier in another context, you can specify the #[path] attribute like so:

#[path = "řųśť"]
mod rust_module;

fn main() {}

Conclusion

Rust Error E0754 is related to the use of non-ASCII identifier names in an invalid context. To fix this error, you need to ensure that non-ASCII identifiers are used only in acceptable scenarios, such as inlined module names or with the #[path] attribute. By following these rules and using valid constructs in your code, you can easily resolve Rust Error E0754 and focus on writing efficient and maintainable Rust programs.