Rust Error E0599 — No Method Found

What Does This Error Mean?

Rust error E0599 means you called a method on a type that does not have that method. This can happen because of a typo in the method name, the type does not implement the required trait, or the trait providing the method has not been imported. Fix it by checking the method name spelling, implementing the required trait, or adding a use statement to bring the trait into scope.

Affected Models

Rust 1.0 and later
All Rust editions (2015, 2018, 2021)
cargo build and rustc

Common Causes

Typo in the method name — Rust method names are case-sensitive
The method is defined on a trait that has not been imported with a use statement
Calling an iterator method on a non-iterator type without calling .iter() first
The type does not implement the trait that provides the method
Calling a method on a reference (&T) when the method is defined on the owned type T, or vice versa

How to Fix It

Check the method name in the error for typos. Compare it to the documentation for that type on doc.rust-lang.org.

Rust will sometimes suggest the correct method name if it finds something similar. Look for 'did you mean' in the error output.
If the method comes from a trait (such as an iterator adapter or a Write method), add the trait to your use statement at the top of the file.

Example: use std::io::Write; — methods from traits are only available when the trait is in scope.
If you have a Vec or array and want to call iterator methods like .map() or .filter(), call .iter() first to get an iterator.

Example: my_vec.iter().map(|x| x * 2) — calling .map() directly on a Vec will cause E0599.
If the method requires a trait your type does not implement, implement it. Common examples: add #[derive(Clone)] to use .clone(), or implement Iterator to use .next().

The compiler hint often tells you which trait you need to implement.
If you are calling the method on a reference, try dereferencing first with *, or check if the method takes &self or self.

Rust usually auto-derefs for method calls, but in some cases you may need to adjust whether you pass a reference or owned value.

When to Call a Professional

E0599 is a compile-time error. The compiler tells you the method name and the type it was called on. It sometimes suggests similar method names or missing trait implementations. Read the full compiler hint — Rust is often very specific about what you need to do.

Frequently Asked Questions

Why does Rust require importing traits to use their methods?

Traits in Rust can be implemented by many types, and two different traits could have methods with the same name. By requiring an explicit use statement, Rust makes it clear which trait's method you mean. This avoids ambiguity and keeps code readable — you can always see which traits are in scope.

The method definitely exists in the docs — why does Rust say it is not found?

The most common reason is that the method is part of a trait, not directly on the type. Check the docs page — if the method is listed under an 'impl TraitName for Type' section, you need to import that trait. Add 'use crate::TraitName;' or 'use std::path::TraitName;' to your file.

Rust says the method is not found for &MyStruct but I defined it on MyStruct — what is happening?

Rust usually handles this automatically through auto-deref, but sometimes it does not. Try calling the method through an explicit dereference: (*my_ref).my_method(). Alternatively, make sure your method signature takes &self rather than self so it works on references too.