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# Error code E0061

An invalid number of arguments was passed when calling a function.

Erroneous code example:

    #![allow(unused)]
    fn main() {
    fn f(u: i32) {}

    f(); // error!
    }

The number of arguments passed to a function must match the number of arguments specified in the function signature.

For example, a function like:

    #![allow(unused)]
    fn main() {
    fn f(a: u16, b: &str) {}
    }

Must always be called with exactly two arguments, e.g., `f(2, "test")`.

Note that Rust does not have a notion of optional function arguments or variadic functions (except for its C-FFI).