1 error[E0005]: refutable pattern in local binding: `Err(_)` not covered
2 --> $DIR/feature-gate-exhaustive-patterns.rs:8:9
4 LL | let Ok(_x) = foo();
5 | ^^^^^^ pattern `Err(_)` not covered
7 = note: `let` bindings require an "irrefutable pattern", like a `struct` or an `enum` with only one variant
8 = note: for more information, visit https://doc.rust-lang.org/book/ch18-02-refutability.html
9 note: `Result<u32, !>` defined here
10 --> $SRC_DIR/core/src/result.rs:LL:COL
12 LL | pub enum Result<T, E> {
13 | ---------------------
15 LL | Err(#[stable(feature = "rust1", since = "1.0.0")] E),
17 = note: the matched value is of type `Result<u32, !>`
18 help: you might want to use `if let` to ignore the variant that isn't matched
20 LL | let _x = if let Ok(_x) = foo() { _x } else { todo!() };
21 | +++++++++++ +++++++++++++++++++++++
22 help: alternatively, you might want to use let else to handle the variant that isn't matched
24 LL | let Ok(_x) = foo() else { todo!() };
27 error: aborting due to previous error
29 For more information about this error, try `rustc --explain E0005`.