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 | help: consider assigning a value | LL | let v: isize = 0; | +++ error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0381`.