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

match — exhaustive pattern matching (must cover all cases). if let — single pattern match.

match:

• Exhaustive — the compiler ensures every variant is handled.
• More verbose but more powerful.
• Supports guards, multiple patterns, and destructuring.
• Returns a value from all branches.

1let value = Some(5);
2match value {
3    Some(x) if x > 10 => println!("Big: {}", x),
4    Some(x) => println!("Small: {}", x),
5    None => println!("Nothing"),
6}
7
8// Can bind and return values
9let description = match value {
10    Some(n) => format!("Got {}", n),
11    None => "Empty".to_string(),
12};

if let:

• Matches only one pattern — simpler syntax.
• Good when you only care about one case.
• Can combine with else for the remaining cases.
• Less boilerplate for simple checks.

1let value = Some(5);
2if let Some(x) = value {
3    println!("Got: {}", x);
4}
5
6// With else
7if let Some(x) = value {
8    println!("Got: {}", x);
9} else {
10    println!("Nothing");
11}

When to use:

• Use match when you need to handle all variants or use complex patterns.
• Use if let when you only care about one specific case.
• Use if let for cleaner code when the other branches are trivial.

Common mistakes:

• Forgetting a variant in match — compiler error (exhaustiveness check).
• Using if let when you need to handle multiple cases — use match.
• Not using else with if let when the fallback matters.