diff --git a/compiler/rustc_data_structures/src/vec_cache.rs b/compiler/rustc_data_structures/src/vec_cache.rs index 3b448c056b748..df83d15b5f943 100644 --- a/compiler/rustc_data_structures/src/vec_cache.rs +++ b/compiler/rustc_data_structures/src/vec_cache.rs @@ -76,8 +76,8 @@ impl SlotIndex { index_in_bucket: idx as usize, }; } - // SAFETY: We already ruled out idx 0, so `checked_ilog2` can't return `None`. - let bucket = unsafe { idx.checked_ilog2().unwrap_unchecked() as usize }; + // We already ruled out idx 0, so this `ilog2` never panics (and the check optimizes away) + let bucket = idx.ilog2() as usize; let entries = 1 << bucket; SlotIndex { bucket_idx: bucket - FIRST_BUCKET_SHIFT + 1,