Error code E0137

Note: this error code is no longer emitted by the compiler.

More than one function was declared with the #[main] attribute.

Erroneous code example:

#![allow(unused)]
#![feature(main)]

fn main() {
#[main]
fn foo() {}

#[main]
fn f() {} // error: multiple functions with a `#[main]` attribute
}

This error indicates that the compiler found multiple functions with the #[main] attribute. This is an error because there must be a unique entry point into a Rust program. Example:

#![allow(unused)]
#![feature(main)]

fn main() {
#[main]
fn f() {} // ok!
}