diff --git a/include/boost/static_string/detail/static_string.hpp b/include/boost/static_string/detail/static_string.hpp
index 9bd4b1f..ed54831 100644
--- a/include/boost/static_string/detail/static_string.hpp
+++ b/include/boost/static_string/detail/static_string.hpp
@@ -45,7 +45,7 @@ using smallest_width =
 template<typename To>
 void is_nothrow_convertible_helper(To) noexcept;
 
-// MSVC is unable to parse this inline, so a helper is needed
+// MSVC is unable to parse this as a single expression, so a helper is needed
 template<typename From, typename To, typename = 
     decltype(is_nothrow_convertible_helper<To>(std::declval<From>()))>
 struct is_nothrow_convertible_msvc_helper
diff --git a/include/boost/static_string/static_string.hpp b/include/boost/static_string/static_string.hpp
index b555542..037ac15 100644
--- a/include/boost/static_string/static_string.hpp
+++ b/include/boost/static_string/static_string.hpp
@@ -953,6 +953,9 @@ public:
         size_type index_str,
         size_type count = npos) BOOST_STATIC_STRING_NO_EXCEPTIONS_NOEXCEPT
     {
+        BOOST_STATIC_STRING_THROW_IF(
+          index_str > str.size(), std::out_of_range{"index_str > str.size()"}
+        );
         return insert(index, str.data() + index_str, (std::min)(count, str.size() - index_str));
     }
 
@@ -1967,6 +1970,9 @@ public:
         size_type pos2,
         size_type n2 = npos) BOOST_STATIC_STRING_NO_EXCEPTIONS_NOEXCEPT
     {
+      BOOST_STATIC_STRING_THROW_IF(
+        pos2 > str.size(), std::out_of_range{"pos2 > str.size()"}
+      );
       return replace(pos1, n1, str.data() + pos2, (std::min)(n2, str.size() - pos2));
     }
 
@@ -2010,6 +2016,9 @@ public:
         size_type pos2,
         size_type n2 = npos) BOOST_STATIC_STRING_NO_EXCEPTIONS_NOEXCEPT
     {
+      BOOST_STATIC_STRING_THROW_IF(
+        pos2 > str.size(), std::out_of_range{"pos2 > str.size()"}
+      );
       return replace_unchecked(pos1, n1, str.data() + pos2, (std::min)(n2, str.size() - pos2));
     }