Function body without the value it returns

Built from the repository at commit a8614dc.

A function with a return type must produce a value of that type on every path through its body: as the value of the body's last expression, or with return. A body that ends in a statement such as let, or in nothing, and does not return first, has no value.

Why

The value of a block is the value of its last expression. A caller waits for the function's value, so every path to the end of the body must produce one.

Broken

fn five() -> i64 {
    let n = 5
}

fn main() {
    print(five())
}

What sisu says

error[E0031]: function `five` must return `i64`, but its body has no value
 --> E0031.sisu:3:1
  |
3 | }
  | ^

sisu: 1 error
sisu: for more on a code, run `sisu explain <code>`: E0031

Fixed

fn five() -> i64 {
    let n = 5
    n
}

fn main() {
    print(five())
}