error[E0381]: used binding `v` isn't initialized --> $DIR/borrowck-init-op-equal.rs:3:5 | LL | let v: isize; | - binding declared here but left uninitialized LL | v += 1; | ^^^^^^ `v` used here but it isn't initialized error: aborting due to previous error For more information about this error, try `rustc --explain E0381`.