Variant without its enum

Built from the repository at commit a8614dc.

A variant is named through its enum: Expr.Num(2) and State.Idle, not Num(2) or Idle. This error fires when no function, class, constant or binding takes the name, but an enum has a variant of it.

Why

A variant lives inside its enum, so two enums can each have an Idle, and a class or function can take the name Num beside a variant Expr.Num. Writing the enum's name says which one you mean. When exactly one enum has the variant, the fix inserts its name; when several do, you choose.

Broken

enum Expr {
    Num(i64)
}

fn main() {
    let _ = Num(2)
}

What sisu says

error[E0117]: `Num` is a variant of `Expr`; write `Expr.Num`
 --> E0117.sisu:6:13
  |
6 |     let _ = Num(2)
  |             ^^^
  |
help: write `Expr.Num`
  |
6 |     let _ = Expr.Num(2)
  |             +++++

sisu: 1 error
sisu: for more on a code, run `sisu explain <code>`: E0117

Fixed

enum Expr {
    Num(i64)
}

fn main() {
    let _ = Expr.Num(2)
}