RRust By Example

Rust Generics Anti-patterns

Practical generics guide for type parameters and constraints with runnable examples and review-ready checklists.

Topic: Generics

Search intent: High-intent search: "rust anti patterns"

Rust Generics Anti-patterns

Problem

Teams often struggle with type parameters and constraints when code grows quickly and review cycles shorten. This guide turns that into a repeatable process.

Diagnostic checklist

  • Define one concrete failure mode before changing code.
  • Reduce to a minimal example first.
  • Validate assumptions around ownership, mutability, and API boundaries.
  • Keep fix scope small and testable.

Runnable example

rust
fn main() {
    let data = vec![1, 2, 3, 4];
    let sum: i32 = data.iter().sum();
    println!("sum={}", sum);
}

Counterexample

rust
fn main() {
    let s = String::from("hello");
    let moved = s;
    println!("{}", s); // moved value
}

How to decide in production

1. Start with correctness and explicit ownership.

2. Add instrumentation before optimizing.

3. Keep interfaces small and typed.

4. Record tradeoffs directly in code and PR description.

Related reading

Related Guides

Rust Generics Debug Checklist

Practical generics guide for type parameters and constraints with runnable examples and review-ready checklists.

Rust Generics Production Guide

Practical generics guide for type parameters and constraints with runnable examples and review-ready checklists.

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