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

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

match:

• Exhaustive — compiler checks all variants.
• Supports guards, multiple patterns.
• Returns a value from all branches.
• More verbose but more powerful.

1let x = Some(5);
2match x {
3    Some(n) if n > 10 => println!("Big: {}", n),
4    Some(n) => println!("Small: {}", n),
5    None => println!("Nothing"),
6}
7
8let result = match x {
9    Some(n) => n * 2,
10    None => 0,
11};

if let:

• Matches one pattern only.
• Simpler syntax.
• Can chain with else.
• Reduces boilerplate.

1if let Some(value) = x {
2    println!("Got: {}", value);
3} else {
4    println!("Nothing");
5}

When to use:

• Use match for multi-case pattern matching.
• Use if let for single-case checks.
• Use if let for simple fallbacks.

Common mistakes:

• Missing a variant in match.
• Using if let when multiple cases needed.
• Forgetting else when needed.