Code
enum Foo {
One,
Two,
}
fn main() {
Foo::One = Foo::One;
}Current output
error[E0005]: refutable pattern in local binding
--> src/main.rs:7:5
|
7 | Foo::One = Foo::One;
| ^^^^^^^^ pattern `Foo::Two` not covered
|
= note: `let` bindings require an "irrefutable pattern", like a `struct` or an `enum` with only one variant
= note: for more information, visit https://doc.rust-lang.org/book/ch19-02-refutability.html
note: `Foo` defined here
--> src/main.rs:1:6
|
1 | enum Foo {
| ^^^
2 | One,
3 | Two,
| --- not covered
= note: the matched value is of type `Foo`
help: you might want to use `if let` to ignore the variant that isn't matched
|
7 | if Foo::One = Foo::One { todo!() };
| ++ +++++++++++
For more information about this error, try `rustc --explain E0005`.Desired output
Rationale and extra context
Foo::One on the left of the = here isn't actually a pattern. It's an (invalid?) assignee expression.- The diagnostic says "
let bindings require...", but this isn't a let binding.
- The suggested
if Foo::One = Foo::One { todo!() }; is invalid code, since there's no let.
See also rust-lang/reference#2280
Other cases
Rust Version
Reproducible on the playground with version 1.98.0-nightly (2026-06-05 8954863c81df429ebf96)
Anything else?
No response
Code
Current output
Desired output
Rationale and extra context
Foo::Oneon the left of the=here isn't actually a pattern. It's an (invalid?) assignee expression.letbindings require...", but this isn't aletbinding.if Foo::One = Foo::One { todo!() };is invalid code, since there's nolet.See also rust-lang/reference#2280
Other cases
Rust Version
Anything else?
No response