TIL RUST #12: if let Pattern Matching and debug_assert!

if let Pattern Matching

if let statements provide a concise way to pattern match on enums and extract values, especially useful for Option types. They combine conditional checking with destructuring in a single expression.

fn main(){
    let number = Some(7);

    // if let destructures Option and binds the inner value
    if let Some(i) = number {
        println!("Matched {:?}!", i);
    }
}

• if let Some(i) = number destructures Option types. When number is Some(7), the pattern Some(i) matches and binds 7 to i.
• Unlike full match statements, if let only handles the cases you specify, making it ideal for concise Option handling.

The debug_assert! macro

Unlike in C++, Rust’s assert! macro is always checked. However, we can use the debug_assert! macro for assertions that are skipped in optimized builds.

• Use assert! for uncompromisable safety nets (e.g., bounds in unsafe blocks).
• Opt for debug_assert! for developer-time validations.