book/listings/ch18-patterns-and-matching/listing-18-08/output.txt

$ cargo run
   Compiling patterns v0.1.0 (file:///projects/patterns)
error[E0005]: refutable pattern in local binding: `None` not covered
 --> src/main.rs:3:9
  |
3 |     let Some(x) = some_option_value;
  |         ^^^^^^^ pattern `None` 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/ch18-02-refutability.html
note: `Option<i32>` defined here
 --> /rustc/d5a82bbd26e1ad8b7401f6a718a9c57c96905483/library/core/src/option.rs:518:1
  |
  = note: 
/rustc/d5a82bbd26e1ad8b7401f6a718a9c57c96905483/library/core/src/option.rs:522:5: not covered
  = note: the matched value is of type `Option<i32>`
help: you might want to use `if let` to ignore the variant that isn't matched
  |
3 |     let x = if let Some(x) = some_option_value { x } else { todo!() };
  |     ++++++++++                                 ++++++++++++++++++++++
help: alternatively, you might want to use let else to handle the variant that isn't matched
  |
3 |     let Some(x) = some_option_value else { todo!() };
  |                                     ++++++++++++++++

For more information about this error, try `rustc --explain E0005`.
error: could not compile `patterns` due to previous error