error[E0004]: non-exhaustive patterns: `Ok(_)` not covered
  --> $DIR/uninhabited-patterns.rs:34:11
   |
LL |     match x {
   |           ^ pattern `Ok(_)` not covered
   |
note: `Result<Box<NotSoSecretlyEmpty>, &[Result<!, !>]>` defined here
  --> $SRC_DIR/core/src/result.rs:LL:COL
  ::: $SRC_DIR/core/src/result.rs:LL:COL
   |
   = note: not covered
   = note: the matched value is of type `Result<Box<NotSoSecretlyEmpty>, &[Result<!, !>]>`
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
   |
LL ~         Err(&[..]) => (),
LL ~         Ok(_) => todo!(),
   |

error: unreachable pattern
  --> $DIR/uninhabited-patterns.rs:43:9
   |
LL |         Err(Ok(_y)) => (),
   |         ^^^^^^^^^^^-------
   |         |
   |         matches no values because `NotSoSecretlyEmpty` is uninhabited
   |         help: remove the match arm
   |
   = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
note: the lint level is defined here
  --> $DIR/uninhabited-patterns.rs:4:9
   |
LL | #![deny(unreachable_patterns)]
   |         ^^^^^^^^^^^^^^^^^^^^

error: unreachable pattern
  --> $DIR/uninhabited-patterns.rs:46:15
   |
LL |     while let Some(_y) = foo() {
   |               ^^^^^^^^ matches no values because `NotSoSecretlyEmpty` is uninhabited
   |
   = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types

error: aborting due to 3 previous errors

For more information about this error, try `rustc --explain E0004`.