How to fix Rust E0061 this function takes N arguments but M were supplied

Compiler Errors

2026-04-17T12:05:42+00:00

Fix Rust E0061 by ensuring the number of arguments in your function call matches the number of parameters defined in the function signature.

The error E0061 occurs because you called a function with the wrong number of arguments. Check the function definition to see how many parameters it expects, then update your function call to match that count exactly.

fn add(a: i32, b: i32) -> i32 {
    a + b
}

fn main() {
    // Correct: 2 arguments match the 2 parameters
    let result = add(1, 2);
    
    // Incorrect: E0061 - 1 argument supplied, 2 expected
    // let result = add(1); 
}