Understanding Rust Generics

Rust’s type system is one of its most powerful features. Generics let you write code that works with many types without sacrificing type safety or runtime performance.

Why Generics Matter

Without generics you’d write the same logic over and over for different types. With generics, the compiler stamps out specialised versions at compile time—zero runtime overhead.

fn largest<T: PartialOrd>(list: &[T]) -> &T {
    let mut largest = &list[0];
    for item in list.iter() {
        if item > largest {
            largest = item;
        }
    }
    largest
}

Generic Structs

struct Point<T> {
    x: T,
    y: T,
}

impl<T> Point<T> {
    fn x(&self) -> &T {
        &self.x
    }
}

Trait Bounds

Trait bounds constrain what types are valid for a generic parameter:

use std::fmt::Display;

fn print_largest<T: PartialOrd + Display>(list: &[T]) {
    let result = largest(list);
    println!("The largest member is {result}");
}

Conclusion

Generics are a fundamental Rust feature that eliminate duplication while preserving full type safety. Master them early and your codebase will thank you.