diff --git a/include/boost/regex/concepts.hpp b/include/boost/regex/concepts.hpp
index 864bed24..7a3a8470 100644
--- a/include/boost/regex/concepts.hpp
+++ b/include/boost/regex/concepts.hpp
@@ -205,6 +205,8 @@ struct RegexTraitsConcept
    const traits m_ctraits;
    const char_type* m_pointer;
    char_type m_char;
+private:
+   RegexTraitsConcept& operator=(RegexTraitsConcept&);
 };
 
 //
@@ -403,6 +405,8 @@ struct BaseRegexConcept
       match_results_type m3(m1);
       m1 = m2;
 
+      int ival = 0;
+
       mr_size_type mrs = m_cresults.size();
       ignore_unused_variable_warning(mrs);
       mrs = m_cresults.max_size();
@@ -411,14 +415,14 @@ struct BaseRegexConcept
       ignore_unused_variable_warning(b);
       mr_difference_type mrd = m_cresults.length();
       ignore_unused_variable_warning(mrd);
-      mrd = m_cresults.length(mrs);
+      mrd = m_cresults.length(ival);
       ignore_unused_variable_warning(mrd);
       mrd = m_cresults.position();
       ignore_unused_variable_warning(mrd);
       mrd = m_cresults.position(mrs);
       ignore_unused_variable_warning(mrd);
 
-      mr_const_reference mrcr = m_cresults[m_size];
+      mr_const_reference mrcr = m_cresults[ival];
       ignore_unused_variable_warning(mrcr);
       mr_const_reference mrcr2 = m_cresults.prefix();
       ignore_unused_variable_warning(mrcr2);
@@ -778,6 +782,8 @@ struct BoostRegexConcept
          | global_regex_namespace::regex_constants::format_no_copy
          | global_regex_namespace::regex_constants::format_first_only;
 
+      (void)mopts;
+
       function_requires<RegexConcept<Regex> >();
       const global_regex_namespace::regex_error except(global_regex_namespace::regex_constants::error_collate);
       std::ptrdiff_t pt = except.position();
diff --git a/include/boost/regex/v4/basic_regex_creator.hpp b/include/boost/regex/v4/basic_regex_creator.hpp
index c3b93e63..ac0408ab 100644
--- a/include/boost/regex/v4/basic_regex_creator.hpp
+++ b/include/boost/regex/v4/basic_regex_creator.hpp
@@ -572,7 +572,7 @@ re_syntax_base* basic_regex_creator<charT, traits>::append_set(
             // Oops error:
             return 0;
          }
-		 BOOST_ASSERT(c3[1] == 0);
+         BOOST_ASSERT(c3[1] == charT(0));
          for(unsigned i = 0; i < (1u << CHAR_BIT); ++i)
          {
             c3[0] = static_cast<charT>(i);
diff --git a/include/boost/regex/v4/match_results.hpp b/include/boost/regex/v4/match_results.hpp
index 72538fc0..024cd03c 100644
--- a/include/boost/regex/v4/match_results.hpp
+++ b/include/boost/regex/v4/match_results.hpp
@@ -88,7 +88,7 @@ public:
          return m_subs[sub].length();
       return 0;
    }
-   difference_type position(unsigned int sub = 0) const
+   difference_type position(size_type sub = 0) const
    {
       sub += 2;
       if(sub < m_subs.size())
diff --git a/include/boost/regex/v4/regex_replace.hpp b/include/boost/regex/v4/regex_replace.hpp
index a852ffec..0dabba16 100644
--- a/include/boost/regex/v4/regex_replace.hpp
+++ b/include/boost/regex/v4/regex_replace.hpp
@@ -45,7 +45,7 @@ OutputIterator regex_replace(OutputIterator out,
    }
    else
    {
-      BidirectionalIterator last_m = first;
+      BidirectionalIterator last_m(first);
       while(i != j)
       {
          if(!(flags & regex_constants::format_no_copy))