Index: boost/xpressive/detail/dynamic/parse_charset.hpp
===================================================================
--- boost/xpressive/detail/dynamic/parse_charset.hpp	(revision 84007)
+++ boost/xpressive/detail/dynamic/parse_charset.hpp	(working copy)
@@ -246,6 +246,7 @@
             case token_charset_hyphen:
             case token_charset_invert:
                 begin = iprev2; // un-get these tokens and fall through
+                BOOST_FALLTHROUGH;
             case token_literal:
                 ch_next = *begin++;
                 BOOST_XPR_ENSURE_(ch_prev <= ch_next, error_range, "invalid charset range");
@@ -264,7 +265,8 @@
                     chset.set_range(ch_prev, esc.ch_, rxtraits, icase);
                     continue;
                 }
-            case token_charset_end: // fall through
+                BOOST_FALLTHROUGH;
+            case token_charset_end:
             default:                // not a range.
                 begin = iprev;      // backup to hyphen token
                 chset.set_char(ch_prev, rxtraits, icase);
Index: boost/xpressive/detail/dynamic/parser_traits.hpp
===================================================================
--- boost/xpressive/detail/dynamic/parser_traits.hpp	(revision 84007)
+++ boost/xpressive/detail/dynamic/parser_traits.hpp	(working copy)
@@ -394,9 +394,9 @@
         case BOOST_XPR_CHAR_(char_type, 'm'): this->flag_(!set, single_line); break;
         case BOOST_XPR_CHAR_(char_type, 's'): this->flag_(!set, not_dot_newline); break;
         case BOOST_XPR_CHAR_(char_type, 'x'): this->flag_(set, ignore_white_space); break;
-        case BOOST_XPR_CHAR_(char_type, ':'): ++begin; // fall-through
+        case BOOST_XPR_CHAR_(char_type, ':'): ++begin; BOOST_FALLTHROUGH;
         case BOOST_XPR_CHAR_(char_type, ')'): return token_no_mark;
-        case BOOST_XPR_CHAR_(char_type, '-'): if(false == (set = !set)) break; // else fall-through
+        case BOOST_XPR_CHAR_(char_type, '-'): if(false == (set = !set)) break; BOOST_FALLTHROUGH;
         default: BOOST_THROW_EXCEPTION(regex_error(error_paren, "unknown pattern modifier"));
         }
         while(BOOST_XPR_ENSURE_(++begin != end, error_paren, "incomplete extension"));
Index: boost/xpressive/match_results.hpp
===================================================================
--- boost/xpressive/match_results.hpp	(revision 84007)
+++ boost/xpressive/match_results.hpp	(working copy)
@@ -1096,11 +1096,12 @@
             case BOOST_XPR_CHAR_(char_type, ':'):
                 if(metacolon)
                 {
+                    BOOST_FALLTHROUGH;
             case BOOST_XPR_CHAR_(char_type, ')'):
                     ++cur;
                     return out;
                 }
-                // else fall-through
+                BOOST_FALLTHROUGH;
 
             default:
                 *out++ = *cur++;
Index: boost/xpressive/regex_compiler.hpp
===================================================================
--- boost/xpressive/regex_compiler.hpp	(revision 84007)
+++ boost/xpressive/regex_compiler.hpp	(working copy)
@@ -282,7 +282,7 @@
             break;
         case 2:
             seq = detail::make_dynamic<BidiIter>(alternate_matcher()) | seq;
-            // fall-through
+            BOOST_FALLTHROUGH;
         default:
             seq |= this->parse_sequence(tmp, end);
         }
@@ -322,13 +322,15 @@
             break;
 
         case token_negative_lookahead:
-            negative = true; // fall-through
+            negative = true;
+            BOOST_FALLTHROUGH;
         case token_positive_lookahead:
             lookahead = true;
             break;
 
         case token_negative_lookbehind:
-            negative = true; // fall-through
+            negative = true;
+            BOOST_FALLTHROUGH;
         case token_positive_lookbehind:
             lookbehind = true;
             break;
@@ -342,10 +344,16 @@
             {
                 switch(this->traits_.get_token(begin, end))
                 {
-                case token_group_end: return this->parse_atom(begin, end);
-                case token_escape: BOOST_XPR_ENSURE_(begin != end, error_escape, "incomplete escape sequence");
-                case token_literal: ++begin;
-                default:;
+                case token_group_end:
+                    return this->parse_atom(begin, end);
+                case token_escape:
+                    BOOST_XPR_ENSURE_(begin != end, error_escape, "incomplete escape sequence");
+                    BOOST_FALLTHROUGH;
+                case token_literal:
+                    ++begin;
+                    break;
+                default:
+                    break;
                 }
             }
             break;
@@ -688,11 +696,17 @@
         {
             switch(this->traits_.get_token(begin, end))
             {
-            case token_quote_meta_end: return string_type(old_begin, old_end);
-            case token_escape: BOOST_XPR_ENSURE_(begin != end, error_escape, "incomplete escape sequence");
+            case token_quote_meta_end:
+                return string_type(old_begin, old_end);
+            case token_escape:
+                BOOST_XPR_ENSURE_(begin != end, error_escape, "incomplete escape sequence");
+                BOOST_FALLTHROUGH;
             case token_invalid_quantifier:
-            case token_literal: ++begin;
-            default:;
+            case token_literal:
+                ++begin;
+                BOOST_FALLTHROUGH;
+            default:
+                break;
             }
         }
         return string_type(old_begin, begin);