Struct PendingShiftCheck 

struct PendingShiftCheck {
    block: BlockId,
    amount: Operand,
    cond_local: LocalId,
    cast_local: Option<LocalId>,
}

A shift overflow check whose shift operation is not in the same block: rustc evaluates the shift operands (which is when it emits the overflow check) before computing the destination place, so when that computation involves a function call (e.g. out[i] = x >> y through an overloaded IndexMut), the check ends up separated from the shift by the call terminator. See issue #1041. These asserts are only ever emitted by the compiler, so instead of following the control flow we record the check and find the matching shift over the whole body in resolve_pending_shift_check.

Fields

block: BlockId

The block containing the check.

amount: Operand

The checked shift amount; used to find the shift.

cond_local: LocalId

The comparison result asserted by the check. Identifies the check’s statements to remove.

cast_local: Option<LocalId>

The y as uN cast temporary, when the amount is cast before the comparison; also removed.