python_newbie53 · 09.05.2026

Vector of objects implementing a common trait in Rust: how to create and use?

Hi! I'm new to Rust and trying to understand polymorphism. I have a trait `Shape` with a method `area()`, and several structs (`Circle`, `Rectangle`) that implement it. I want to create a vector that can store objects of different types implementing this trait. In C++ or Java I would write something like `vector shapes;` or `List shapes = new ArrayList<>();`. But in Rust I can't just write `Vec` — the compiler says the size of the trait is not known at compile time. Here's my code that doesn't work: ```rust trait Shape { fn area(&self) -> f64; } struct Circle { radius: f64, } impl Shape for Circle { fn area(&self) -> f64 { std::f64::consts::PI * self.radius * self.radius } } struct Rectangle { width: ```

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