diff --git a/include/boost/core/noinit_adaptor.hpp b/include/boost/core/noinit_adaptor.hpp
index 13ce4c8..962b6e4 100644
--- a/include/boost/core/noinit_adaptor.hpp
+++ b/include/boost/core/noinit_adaptor.hpp
@@ -56,6 +56,7 @@ struct noinit_adaptor
     template<class U>
     void destroy(U* p) {
         p->~U();
+        (void)p;
     }
 };
 
diff --git a/include/boost/core/span.hpp b/include/boost/core/span.hpp
index 39f5cef..c44af84 100644
--- a/include/boost/core/span.hpp
+++ b/include/boost/core/span.hpp
@@ -146,8 +146,12 @@ struct span_store<T, boost::dynamic_extent> {
 
 template<class T, std::size_t E>
 struct span_bytes {
-    static constexpr std::size_t value = E == boost::dynamic_extent ?
-        boost::dynamic_extent : sizeof(T) * E;
+    static constexpr std::size_t value = sizeof(T) * E;
+};
+
+template<class T>
+struct span_bytes<T, boost::dynamic_extent> {
+    static constexpr std::size_t value = boost::dynamic_extent;
 };
 
 } /* detail */