error[E0381]: used binding `x` isn't initialized
  --> $DIR/borrowck-storage-dead.rs:16:17
   |
LL |         let x: i32;
   |             - binding declared here but left uninitialized
LL |         let _ = x + 1;
   |                 ^ `x` used here but it isn't initialized
   |
help: consider assigning a value
   |
LL |         let x: i32 = 42;
   |                    ++++

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0381`.