error[E0005]: refutable pattern in local binding: `Err(_)` not covered
  --> $DIR/recursive-types-are-not-uninhabited.rs:6:9
   |
LL |     let Ok(x) = res;
   |         ^^^^^ pattern `Err(_)` 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
help: you might want to use `if let` to ignore the variant that isn't matched
   |
LL |     if let Ok(x) = res { /* */ }
   |

error[E0381]: use of possibly-uninitialized variable: `x`
  --> $DIR/recursive-types-are-not-uninhabited.rs:8:5
   |
LL |     x
   |     ^ use of possibly-uninitialized `x`

error: aborting due to 2 previous errors

Some errors have detailed explanations: E0005, E0381.
For more information about an error, try `rustc --explain E0005`.