diff --git a/library/core/src/num/int_sqrt.rs b/library/core/src/num/int_sqrt.rs
index 7d02d456a4c02..5755294623f40 100644
--- a/library/core/src/num/int_sqrt.rs
+++ b/library/core/src/num/int_sqrt.rs
@@ -159,6 +159,10 @@ macro_rules! unsigned_fn {
 }
 
 /// Generates the first stage of the computation after normalization.
+///
+/// # Safety
+///
+/// `$n` must be nonzero.
 macro_rules! first_stage {
     ($original_bits:literal, $n:ident) => {{
         const N_SHIFT: u32 = $original_bits - 8;
@@ -169,6 +173,10 @@ macro_rules! first_stage {
 }
 
 /// Generates a middle stage of the computation.
+///
+/// # Safety
+///
+/// `$s` must be nonzero.
 macro_rules! middle_stage {
     ($original_bits:literal, $ty:ty, $n:ident, $s:ident, $r:ident) => {{
         // Inform the optimizer that `$s` is nonzero. This will allow it to
@@ -219,6 +227,10 @@ macro_rules! middle_stage {
 }
 
 /// Generates the last stage of the computation before denormalization.
+///
+/// # Safety
+///
+/// `$s` must be nonzero.
 macro_rules! last_stage {
     ($ty:ty, $n:ident, $s:ident, $r:ident) => {{
         // Inform the optimizer that `$s` is nonzero. This will allow it to
@@ -226,7 +238,7 @@ macro_rules! last_stage {
         // division below.
         //
         // SAFETY: See the proof in the `middle_stage` macro above.
-        unsafe { core::hint::assert_unchecked($s != 0) };
+        unsafe { crate::hint::assert_unchecked($s != 0) };
 
         const HALF_BITS: u32 = <$ty>::BITS >> 1;
         const QUARTER_BITS: u32 = <$ty>::BITS >> 2;
@@ -248,6 +260,10 @@ macro_rules! last_stage {
 
 /// Generates the stages of the computation between normalization and
 /// denormalization for [`u16`](prim@u16).
+///
+/// # Safety
+///
+/// `$n` must be nonzero.
 macro_rules! u16_stages {
     ($n:ident) => {{
         let (s, r) = first_stage!(16, $n);
@@ -257,6 +273,10 @@ macro_rules! u16_stages {
 
 /// Generates the stages of the computation between normalization and
 /// denormalization for [`u32`](prim@u32).
+///
+/// # Safety
+///
+/// `$n` must be nonzero.
 macro_rules! u32_stages {
     ($n:ident) => {{
         let (s, r) = first_stage!(32, $n);
@@ -267,6 +287,10 @@ macro_rules! u32_stages {
 
 /// Generates the stages of the computation between normalization and
 /// denormalization for [`u64`](prim@u64).
+///
+/// # Safety
+///
+/// `$n` must be nonzero.
 macro_rules! u64_stages {
     ($n:ident) => {{
         let (s, r) = first_stage!(64, $n);
@@ -278,6 +302,10 @@ macro_rules! u64_stages {
 
 /// Generates the stages of the computation between normalization and
 /// denormalization for [`u128`](prim@u128).
+///
+/// # Safety
+///
+/// `$n` must be nonzero.
 macro_rules! u128_stages {
     ($n:ident) => {{
         let (s, r) = first_stage!(128, $n);