Rust: What is the difference between match and if let?

match — exhaustive pattern matching covering all cases. if let — matches a single pattern.

match:

• Exhaustive — compiler ensures every variant is handled.
• Supports guards (if x > 5), multiple patterns, and destructuring.
• Returns a value from all branches (expression).
• More verbose but more powerful.

1let num = Some(42);
2match num {
3    Some(x) if x > 100 => println!("Large: {}", x),
4    Some(x) => println!("Small: {}", x),
5    None => println!("Nothing"),
6}
7
8// Binding in match
9let result = match num {
10    Some(n) => n * 2,
11    None => 0,
12};

if let:

• Matches only one pattern — simpler syntax.
• Good when you only care about one case.
• Can chain with else if let or else.
• Less boilerplate for simple checks.

1if let Some(value) = num {
2    println!("Got: {}", value);
3}
4
5// Multiple patterns
6if let Some(x) = num {
7    println!("Got: {}", x);
8} else if let None = num {
9    println!("Nothing");
10}

When to use:

• Use match for complex pattern matching with multiple cases.
• Use if let when you only care about one specific pattern.
• Use if let for cleaner code when the fallback is trivial.

Common mistakes:

• Forgetting a variant in match — compiler error.
• Using if let when you need multiple cases — use match.
• Not using else with if let when the other case matters.