diff --git a/source/containers.tex b/source/containers.tex
index da77c7313d..d96979e3b2 100644
--- a/source/containers.tex
+++ b/source/containers.tex
@@ -18315,7 +18315,7 @@
 
     // \ref{span.elem}, element access
     constexpr reference operator[](size_type idx) const;
-    constexpr reference at(size_type idx) const;
+    constexpr reference at(size_type idx) const;                            // freestanding-deleted
     constexpr reference front() const;
     constexpr reference back() const;
     constexpr pointer data() const noexcept;