diff --git a/include/boost/fixed_string/fixed_string.hpp b/include/boost/fixed_string/fixed_string.hpp
index 0163181..0d8a3ce 100644
--- a/include/boost/fixed_string/fixed_string.hpp
+++ b/include/boost/fixed_string/fixed_string.hpp
@@ -1340,7 +1340,6 @@ public:
       return replace(pos1, n1, sv.substr(pos2, n2));
     }
 
-    // impl
     fixed_string&
     replace(
         size_type pos,
@@ -1357,7 +1356,6 @@ public:
       return replace(pos, n1, s, Traits::length(s));
     }
 
-    // impl 
     fixed_string&
     replace(
         size_type pos,
@@ -1422,7 +1420,13 @@ public:
     }
 
     template<typename InputIterator>
+#if GENERATING_DOCUMENTATION
     fixed_string&
+#else
+    typename std::enable_if<
+        detail::is_input_iterator<InputIterator>::value,
+            fixed_string&>::type
+#endif
     replace(
         const_iterator i1,
         const_iterator i2,
@@ -1568,7 +1572,7 @@ public:
     {
       return string_view_type(
         *this).rfind(
-          s, pos);
+          s, pos, n);
     }
 
     /** Finds the last substring equal to the character
diff --git a/include/boost/fixed_string/impl/fixed_string.hpp b/include/boost/fixed_string/impl/fixed_string.hpp
index cf8f982..9d50195 100644
--- a/include/boost/fixed_string/impl/fixed_string.hpp
+++ b/include/boost/fixed_string/impl/fixed_string.hpp
@@ -317,10 +317,28 @@ insert(
     if(size() + count > max_size())
         BOOST_THROW_EXCEPTION(std::length_error{
             "size() + count > max_size()"});
-    Traits::move(
-        &s_[index + count], &s_[index], size() - index);
+    const bool inside = s <= &s_[size()] && s >= &s_[0];
+    if (!inside || (inside && (&s[count - 1] < &s_[index])))
+    {
+      Traits::move(&s_[index + count], &s_[index], size() - index);
+      Traits::copy(&s_[index], s, count);
+    }
+    else
+    {
+      const size_type offset = s - &s_[0];
+      Traits::move(&s_[index + count], &s_[index], size() - index);
+      if (offset < index)
+      {
+        const size_type diff = index - offset;
+        Traits::copy(&s_[index], &s_[offset], diff);
+        Traits::copy(&s_[index + diff], &s_[index + count], count - diff);
+      }
+      else
+      {
+        Traits::copy(&s_[index], &s_[index + count + offset], count);
+      }
+    }
     n_ += count;
-    Traits::copy(&s_[index], s, count);
     term();
     return *this;
 }
@@ -363,12 +381,13 @@ insert(
         BOOST_THROW_EXCEPTION(std::length_error{
             "size() + count > max_size()"});
     std::size_t const index = pos - begin();
-    Traits::move(
-        &s_[index + count], &s_[index], size() - index);
-    n_ += count;
+    if (&*first <= &s_[size()] && &*first >= &s_[0])
+      return insert(index, &*first, count).begin() + index;
+    Traits::move(&s_[index + count], &s_[index], size() - index);
     for(auto it = begin() + index;
             first != last; ++it, ++first)
         Traits::assign(*it, *first);
+    n_ += count;
     term();
     return begin() + index;
 }