error[E0580]: `main` function has wrong type --> $DIR/bad-main.rs:1:1 | LL | fn main(x: isize) { } | ^^^^^^^^^^^^^^^^^ incorrect number of function parameters | = note: expected signature `fn()` found signature `fn(isize)` error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0580`.