1 files changed, 2 insertions, 1 deletions
diff --git a/src/libcore/char/decode.rs b/src/libcore/char/decode.rs
index b71c9c2c40b..ae09251c776 100644
--- a/src/libcore/char/decode.rs
+++ b/src/libcore/char/decode.rs
@@ -87,7 +87,7 @@ impl<I: Iterator<Item = u16>> Iterator for DecodeUtf16<I> {
         };
 
         if u < 0xD800 || 0xDFFF < u {
-            // not a surrogate
+            // SAFETY: not a surrogate
             Some(Ok(unsafe { from_u32_unchecked(u as u32) }))
         } else if u >= 0xDC00 {
             // a trailing surrogate
@@ -107,6 +107,7 @@ impl<I: Iterator<Item = u16>> Iterator for DecodeUtf16<I> {
 
             // all ok, so lets decode it.
             let c = (((u - 0xD800) as u32) << 10 | (u2 - 0xDC00) as u32) + 0x1_0000;
+            // SAFETY: we checked that it's a legal unicode value
             Some(Ok(unsafe { from_u32_unchecked(c) }))
         }
     }