diff --git a/include/boost/parser/detail/text/algorithm.hpp b/include/boost/parser/detail/text/algorithm.hpp
index 9f22affb..058aa584 100644
--- a/include/boost/parser/detail/text/algorithm.hpp
+++ b/include/boost/parser/detail/text/algorithm.hpp
@@ -21,13 +21,13 @@ namespace boost::parser::detail { namespace text {
 
     namespace detail {
         template<typename Iter>
-        std::ptrdiff_t distance(Iter first, Iter last, non_sentinel_tag)
+        std::ptrdiff_t distance(Iter const & first, Iter const & last, non_sentinel_tag)
         {
             return std::distance(first, last);
         }
 
         template<typename Iter, typename Sentinel>
-        std::ptrdiff_t distance(Iter first, Sentinel last, sentinel_tag)
+        std::ptrdiff_t distance(Iter first, Sentinel const & last, sentinel_tag)
         {
             std::ptrdiff_t retval = 0;
             while (first != last) {
@@ -41,7 +41,7 @@ namespace boost::parser::detail { namespace text {
     /** Range-friendly version of `std::distance()`, taking an iterator and a
         sentinel. */
     template<typename Iter, typename Sentinel>
-    std::ptrdiff_t distance(Iter first, Sentinel last)
+    std::ptrdiff_t distance(Iter const & first, Sentinel const & last)
     {
         return detail::distance(
             first,
@@ -55,7 +55,7 @@ namespace boost::parser::detail { namespace text {
     /** Range-friendly version of `std::find()`, taking an iterator and a
         sentinel. */
     template<typename BidiIter, typename Sentinel, typename T>
-    BidiIter find(BidiIter first, Sentinel last, T const & x)
+    BidiIter find(BidiIter first, Sentinel const & last, T const & x)
     {
         while (first != last) {
             if (*first == x)
@@ -68,7 +68,7 @@ namespace boost::parser::detail { namespace text {
     /** A range-friendly compliment to `std::find()`; returns an iterator to
         the first element not equal to `x`. */
     template<typename BidiIter, typename Sentinel, typename T>
-    BidiIter find_not(BidiIter first, Sentinel last, T const & x)
+    BidiIter find_not(BidiIter first, Sentinel const & last, T const & x)
     {
         while (first != last) {
             if (*first != x)
@@ -81,7 +81,7 @@ namespace boost::parser::detail { namespace text {
     /** Range-friendly version of `std::find_if()`, taking an iterator and a
         sentinel. */
     template<typename BidiIter, typename Sentinel, typename Pred>
-    BidiIter find_if(BidiIter first, Sentinel last, Pred p)
+    BidiIter find_if(BidiIter first, Sentinel const & last, Pred p)
     {
         while (first != last) {
             if (p(*first))
@@ -94,7 +94,7 @@ namespace boost::parser::detail { namespace text {
     /** Range-friendly version of `std::find_if_not()`, taking an iterator and
         a sentinel. */
     template<typename BidiIter, typename Sentinel, typename Pred>
-    BidiIter find_if_not(BidiIter first, Sentinel last, Pred p)
+    BidiIter find_if_not(BidiIter first, Sentinel const & last, Pred p)
     {
         while (first != last) {
             if (!p(*first))
@@ -107,7 +107,7 @@ namespace boost::parser::detail { namespace text {
     /** Analogue of `std::find()` that finds the last value in `[first, last)`
         equal to `x`. */
     template<typename BidiIter, typename T>
-    BidiIter find_backward(BidiIter first, BidiIter last, T const & x)
+    BidiIter find_backward(BidiIter const & first, BidiIter const & last, T const & x)
     {
         auto it = last;
         while (it != first) {
@@ -120,7 +120,7 @@ namespace boost::parser::detail { namespace text {
     /** Analogue of `std::find()` that finds the last value in `[first, last)`
         not equal to `x`. */
     template<typename BidiIter, typename T>
-    BidiIter find_not_backward(BidiIter first, BidiIter last, T const & x)
+    BidiIter find_not_backward(BidiIter const & first, BidiIter const & last, T const & x)
     {
         auto it = last;
         while (it != first) {
@@ -133,7 +133,7 @@ namespace boost::parser::detail { namespace text {
     /** Analogue of `std::find()` that finds the last value `v` in `[first,
         last)` for which `p(v)` is true. */
     template<typename BidiIter, typename Pred>
-    BidiIter find_if_backward(BidiIter first, BidiIter last, Pred p)
+    BidiIter find_if_backward(BidiIter const & first, BidiIter const & last, Pred p)
     {
         auto it = last;
         while (it != first) {
@@ -146,7 +146,7 @@ namespace boost::parser::detail { namespace text {
     /** Analogue of `std::find()` that finds the last value `v` in `[first,
         last)` for which `p(v)` is false. */
     template<typename BidiIter, typename Pred>
-    BidiIter find_if_not_backward(BidiIter first, BidiIter last, Pred p)
+    BidiIter find_if_not_backward(BidiIter const & first, BidiIter const & last, Pred p)
     {
         auto it = last;
         while (it != first) {
@@ -166,7 +166,7 @@ namespace boost::parser::detail { namespace text {
         the first element of the subsequence.  Subranges passed to `f` are
         non-overlapping. */
     template<typename FwdIter, typename Sentinel, typename Func>
-    Func foreach_subrange(FwdIter first, Sentinel last, Func f)
+    Func foreach_subrange(FwdIter first, Sentinel const & last, Func f)
     {
         while (first != last) {
             auto const & x = *first;
@@ -185,7 +185,7 @@ namespace boost::parser::detail { namespace text {
         `proj(e)` each compares equal to `proj()` of the first element of the
         subsequence.  Subranges passed to `f` are non-overlapping. */
     template<typename FwdIter, typename Sentinel, typename Func, typename Proj>
-    Func foreach_subrange(FwdIter first, Sentinel last, Func f, Proj proj)
+    Func foreach_subrange(FwdIter first, Sentinel const & last, Func f, Proj proj)
     {
         using value_type = typename std::iterator_traits<FwdIter>::value_type;
         while (first != last) {
@@ -207,7 +207,7 @@ namespace boost::parser::detail { namespace text {
         is a contiguous subsequence of elements, each of which is equal to
         `x`.  Subranges passed to `f` are non-overlapping. */
     template<typename FwdIter, typename Sentinel, typename T, typename Func>
-    Func foreach_subrange_of(FwdIter first, Sentinel last, T const & x, Func f)
+    Func foreach_subrange_of(FwdIter first, Sentinel const & last, T const & x, Func f)
     {
         while (first != last) {
             first = boost::parser::detail::text::find(first, last, x);
@@ -225,7 +225,7 @@ namespace boost::parser::detail { namespace text {
         is a contiguous subsequence of elements `ei` for which `p(ei)` is
         true.  Subranges passed to `f` are non-overlapping. */
     template<typename FwdIter, typename Sentinel, typename Pred, typename Func>
-    Func foreach_subrange_if(FwdIter first, Sentinel last, Pred p, Func f)
+    Func foreach_subrange_if(FwdIter first, Sentinel const & last, Pred p, Func f)
     {
         while (first != last) {
             first = boost::parser::detail::text::find_if(first, last, p);
@@ -241,7 +241,7 @@ namespace boost::parser::detail { namespace text {
 
     /** Sentinel-friendly version of `std::all_of()`. */
     template<typename Iter, typename Sentinel, typename Pred>
-    bool all_of(Iter first, Sentinel last, Pred p)
+    bool all_of(Iter first, Sentinel const & last, Pred p)
     {
         for (; first != last; ++first) {
             if (!p(*first))
@@ -256,7 +256,7 @@ namespace boost::parser::detail { namespace text {
         typename Sentinel1,
         typename Iter2,
         typename Sentinel2>
-    bool equal(Iter1 first1, Sentinel1 last1, Iter2 first2, Sentinel2 last2)
+    bool equal(Iter1 first1, Sentinel1 const & last1, Iter2 first2, Sentinel2 const & last2)
     {
         for (; first1 != last1 && first2 != last2; ++first1, ++first2) {
             if (*first1 != *first2)
@@ -272,7 +272,7 @@ namespace boost::parser::detail { namespace text {
         typename Iter2,
         typename Sentinel2>
     std::pair<Iter1, Iter2>
-    mismatch(Iter1 first1, Sentinel1 last1, Iter2 first2, Sentinel2 last2)
+    mismatch(Iter1 first1, Sentinel1 const & last1, Iter2 first2, Sentinel2 const & last2)
     {
         for (; first1 != last1 && first2 != last2; ++first1, ++first2) {
             if (*first1 != *first2)
@@ -290,7 +290,10 @@ namespace boost::parser::detail { namespace text {
         typename Iter2,
         typename Sentinel2>
     int lexicographical_compare_three_way(
-        Iter1 first1, Sentinel1 last1, Iter2 first2, Sentinel2 last2)
+        Iter1 const & first1,
+        Sentinel1 const & last1,
+        Iter2 const & first2,
+        Sentinel2 const & last2)
     {
         auto const iters = boost::parser::detail::text::mismatch(first1, last1, first2, last2);
         if (iters.first == last1) {
diff --git a/include/boost/parser/detail/text/transcode_algorithm.hpp b/include/boost/parser/detail/text/transcode_algorithm.hpp
index a8b869c0..b65276be 100644
--- a/include/boost/parser/detail/text/transcode_algorithm.hpp
+++ b/include/boost/parser/detail/text/transcode_algorithm.hpp
@@ -81,7 +81,7 @@ namespace boost::parser::detail { namespace text {
             typename OutIter>
         transcode_result<InputIter, OutIter> transcode_utf_8_to_16(
             InputIter first,
-            Sentinel last,
+            Sentinel const & last,
             std::ptrdiff_t n,
             OutIter out,
             std::input_iterator_tag)
@@ -103,7 +103,7 @@ namespace boost::parser::detail { namespace text {
         template<bool UseN, typename Iter, typename OutIter>
         transcode_result<Iter, OutIter> transcode_utf_8_to_16(
             Iter first,
-            Iter last,
+            Iter const & last,
             std::ptrdiff_t n,
             OutIter out,
             std::random_access_iterator_tag)
@@ -119,7 +119,7 @@ namespace boost::parser::detail { namespace text {
             typename OutIter>
         transcode_result<InputIter, OutIter> transcode_utf_8_to_32(
             InputIter first,
-            Sentinel last,
+            Sentinel const & last,
             std::ptrdiff_t n,
             OutIter out,
             std::input_iterator_tag)
@@ -141,7 +141,7 @@ namespace boost::parser::detail { namespace text {
         template<bool UseN, typename Iter, typename OutIter>
         transcode_result<Iter, OutIter> transcode_utf_8_to_32(
             Iter first,
-            Iter last,
+            Iter const & last,
             std::ptrdiff_t n,
             OutIter out,
             std::random_access_iterator_tag)
@@ -158,7 +158,7 @@ namespace boost::parser::detail { namespace text {
         transcode_result<Iter, OutIter> transcode_to_8(
             tag_t<format::utf8>,
             Iter first,
-            Sentinel last,
+            Sentinel const & last,
             std::ptrdiff_t n,
             OutIter out)
         {
@@ -173,7 +173,7 @@ namespace boost::parser::detail { namespace text {
         transcode_result<Iter, OutIter> transcode_to_16(
             tag_t<format::utf8>,
             Iter first,
-            Sentinel last,
+            Sentinel const & last,
             std::ptrdiff_t n,
             OutIter out)
         {
@@ -189,7 +189,7 @@ namespace boost::parser::detail { namespace text {
         transcode_result<Iter, OutIter> transcode_to_32(
             tag_t<format::utf8>,
             Iter first,
-            Sentinel last,
+            Sentinel const & last,
             std::ptrdiff_t n,
             OutIter out)
         {
@@ -205,7 +205,7 @@ namespace boost::parser::detail { namespace text {
         transcode_result<Iter, OutIter> transcode_to_8(
             tag_t<format::utf16>,
             Iter first,
-            Sentinel last,
+            Sentinel const & last,
             std::ptrdiff_t n,
             OutIter out)
         {
@@ -247,7 +247,7 @@ namespace boost::parser::detail { namespace text {
         transcode_result<Iter, OutIter> transcode_to_16(
             tag_t<format::utf16>,
             Iter first,
-            Sentinel last,
+            Sentinel const & last,
             std::ptrdiff_t n,
             OutIter out)
         {
@@ -261,7 +261,7 @@ namespace boost::parser::detail { namespace text {
         transcode_result<Iter, OutIter> transcode_to_32(
             tag_t<format::utf16>,
             Iter first,
-            Sentinel last,
+            Sentinel const & last,
             std::ptrdiff_t n,
             OutIter out)
         {
@@ -304,7 +304,7 @@ namespace boost::parser::detail { namespace text {
         transcode_result<Iter, OutIter> transcode_to_8(
             tag_t<format::utf32>,
             Iter first,
-            Sentinel last,
+            Sentinel const & last,
             std::ptrdiff_t n,
             OutIter out)
         {
@@ -318,7 +318,7 @@ namespace boost::parser::detail { namespace text {
         transcode_result<Iter, OutIter> transcode_to_16(
             tag_t<format::utf32>,
             Iter first,
-            Sentinel last,
+            Sentinel const & last,
             std::ptrdiff_t n,
             OutIter out)
         {
@@ -332,7 +332,7 @@ namespace boost::parser::detail { namespace text {
         transcode_result<Iter, OutIter> transcode_to_32(
             tag_t<format::utf32>,
             Iter first,
-            Sentinel last,
+            Sentinel const & last,
             std::ptrdiff_t n,
             OutIter out)
         {
diff --git a/include/boost/parser/parser.hpp b/include/boost/parser/parser.hpp
index 1f833da7..578473ce 100644
--- a/include/boost/parser/parser.hpp
+++ b/include/boost/parser/parser.hpp
@@ -455,8 +455,8 @@ namespace boost { namespace parser {
             static constexpr bool do_trace = DoTrace;
             static constexpr bool use_callbacks = UseCallbacks;
 
-            I first_;
-            S last_;
+            I const & first_;
+            S const & last_;
             bool * pass_ = nullptr;
             int * trace_indent_ = nullptr;
             symbol_table_tries_t * symbol_table_tries_ = nullptr;
@@ -524,8 +524,8 @@ namespace boost { namespace parser {
             parse_context(
                 std::bool_constant<DoTrace>,
                 std::bool_constant<UseCallbacks>,
-                I & first,
-                S last,
+                I const & first,
+                S const & last,
                 bool & success,
                 int & indent,
                 ErrorHandler const & error_handler,
@@ -547,8 +547,8 @@ namespace boost { namespace parser {
             parse_context(
                 std::bool_constant<DoTrace>,
                 std::bool_constant<UseCallbacks>,
-                I & first,
-                S last,
+                I const & first,
+                S const & last,
                 bool & success,
                 int & indent,
                 ErrorHandler const & error_handler,
@@ -565,8 +565,8 @@ namespace boost { namespace parser {
             parse_context(
                 std::bool_constant<DoTrace>,
                 std::bool_constant<UseCallbacks>,
-                I & first,
-                S last,
+                I const & first,
+                S const & last,
                 bool & success,
                 int & indent,
                 ErrorHandler const & error_handler,
@@ -852,7 +852,7 @@ namespace boost { namespace parser {
             typename ErrorHandler>
         auto make_context(
             Iter first,
-            Sentinel last,
+            Sentinel const & last,
             bool & success,
             int & indent,
             ErrorHandler const & error_handler,
@@ -882,7 +882,7 @@ namespace boost { namespace parser {
             typename ErrorHandler>
         auto make_context(
             Iter first,
-            Sentinel last,
+            Sentinel const & last,
             bool & success,
             int & indent,
             ErrorHandler const & error_handler,
@@ -910,7 +910,7 @@ namespace boost { namespace parser {
             typename GlobalState>
         auto make_context(
             Iter first,
-            Sentinel last,
+            Sentinel const & last,
             bool & success,
             int & indent,
             ErrorHandler const & error_handler,
@@ -941,7 +941,7 @@ namespace boost { namespace parser {
             typename Callbacks>
         auto make_context(
             Iter first,
-            Sentinel last,
+            Sentinel const & last,
             bool & success,
             int & indent,
             ErrorHandler const & error_handler,
@@ -975,7 +975,7 @@ namespace boost { namespace parser {
             typename GlobalState>
         auto make_context(
             Iter first,
-            Sentinel last,
+            Sentinel const & last,
             bool & success,
             int & indent,
             ErrorHandler const & error_handler,
@@ -1520,7 +1520,7 @@ namespace boost { namespace parser {
         inline void append(nope &, nope &&, bool) {}
 
         template<typename Container, typename Iter, typename Sentinel>
-        void append(Container & c, Iter first, Sentinel last, bool gen_attrs)
+        void append(Container & c, Iter first, Sentinel const & last, bool gen_attrs)
         {
             if (!gen_attrs)
                 return;
@@ -1539,7 +1539,7 @@ namespace boost { namespace parser {
         void append(
             std::optional<Container> & c,
             Iter first,
-            Sentinel last,
+            Sentinel const & last,
             bool gen_attrs)
         {
             if (!gen_attrs)
@@ -1550,7 +1550,7 @@ namespace boost { namespace parser {
         }
 
         template<typename Iter, typename Sentinel>
-        void append(nope &, Iter first, Sentinel last, bool gen_attrs)
+        void append(nope &, Iter first, Sentinel const & last, bool gen_attrs)
         {}
 
         constexpr inline flags default_flags()
@@ -1611,7 +1611,7 @@ namespace boost { namespace parser {
                 typename SkipParser>
             nope operator()(
                 Iter & first,
-                Sentinel last,
+                Sentinel const & last,
                 Context const & context,
                 SkipParser const & skip,
                 flags flags,
@@ -1628,7 +1628,7 @@ namespace boost { namespace parser {
                 typename Attribute>
             void operator()(
                 Iter & first,
-                Sentinel last,
+                Sentinel const & last,
                 Context const & context,
                 SkipParser const & skip,
                 flags flags,
@@ -1639,12 +1639,12 @@ namespace boost { namespace parser {
 
         template<typename Iter, typename Sentinel>
         void
-        skip(Iter & first, Sentinel last, null_parser const & skip_, flags f)
+        skip(Iter & first, Sentinel const & last, null_parser const & skip_, flags f)
         {}
 
         template<typename Iter, typename Sentinel, typename SkipParser>
         void
-        skip(Iter & first, Sentinel last, SkipParser const & skip_, flags f)
+        skip(Iter & first, Sentinel const & last, SkipParser const & skip_, flags f)
         {
             if (!detail::use_skip(f))
                 return;
@@ -1953,7 +1953,7 @@ namespace boost { namespace parser {
         };
 
         template<bool SortedUTF32, typename Iter, typename Sentinel>
-        constexpr auto make_char_range(Iter first, Sentinel last)
+        constexpr auto make_char_range(Iter first, Sentinel const & last)
         {
             return char_range<Iter, Sentinel, SortedUTF32>{
                 BOOST_PARSER_SUBRANGE<Iter, Sentinel>{first, last}};
@@ -2276,7 +2276,7 @@ namespace boost { namespace parser {
         void apply_parser(
             Parser const & parser,
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             flags flags,
@@ -2309,7 +2309,7 @@ namespace boost { namespace parser {
         void apply_parser(
             Parser const & parser,
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             flags flags,
@@ -2331,7 +2331,7 @@ namespace boost { namespace parser {
         void apply_parser(
             Parser const & parser,
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             flags flags,
@@ -2353,7 +2353,7 @@ namespace boost { namespace parser {
         void apply_parser(
             Parser const & parser,
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             flags flags,
@@ -2368,7 +2368,7 @@ namespace boost { namespace parser {
         // API implementations
 
         template<typename Iter, typename Sentinel, typename Parser>
-        auto has_attribute(Iter first, Sentinel last, Parser parser);
+        auto has_attribute(Iter first, Sentinel const & last, Parser parser);
 
         template<typename BaseIter, typename Iter>
         struct scoped_base_assign
@@ -2422,7 +2422,7 @@ namespace boost { namespace parser {
             typename ErrorHandler>
         bool parse_impl(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Parser const & parser,
             ErrorHandler const & error_handler,
             Attr & attr)
@@ -2475,7 +2475,7 @@ namespace boost { namespace parser {
             typename ErrorHandler>
         auto parse_impl(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Parser const & parser,
             ErrorHandler const & error_handler)
         {
@@ -2531,7 +2531,7 @@ namespace boost { namespace parser {
             typename Callbacks>
         bool callback_parse_impl(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Parser const & parser,
             ErrorHandler const & error_handler,
             Callbacks const & callbacks)
@@ -2586,7 +2586,7 @@ namespace boost { namespace parser {
             typename ErrorHandler>
         bool skip_parse_impl(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Parser const & parser,
             SkipParser const & skip,
             ErrorHandler const & error_handler,
@@ -2636,7 +2636,7 @@ namespace boost { namespace parser {
             typename ErrorHandler>
         auto skip_parse_impl(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Parser const & parser,
             SkipParser const & skip,
             ErrorHandler const & error_handler)
@@ -2691,7 +2691,7 @@ namespace boost { namespace parser {
             typename Callbacks>
         bool callback_skip_parse_impl(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Parser const & parser,
             SkipParser const & skip,
             ErrorHandler const & error_handler,
@@ -2841,7 +2841,7 @@ namespace boost { namespace parser {
         T if_full_parse(
             I initial_first,
             I & first,
-            S last,
+            S const & last,
             ErrorHandler const & error_handler,
             T retval)
         {
@@ -3149,7 +3149,7 @@ namespace boost { namespace parser {
             typename SkipParser>
         auto call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -3170,7 +3170,7 @@ namespace boost { namespace parser {
             typename Attribute>
         void call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -3310,7 +3310,7 @@ namespace boost { namespace parser {
             typename SkipParser>
         auto call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -3333,7 +3333,7 @@ namespace boost { namespace parser {
             typename Attribute>
         void call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -3417,7 +3417,7 @@ namespace boost { namespace parser {
             }
 
             Iter & first_;
-            Sentinel last_;
+            Sentinel const & last_;
             Context const & context_;
             SkipParser const & skip_;
             detail::flags flags_;
@@ -3433,7 +3433,7 @@ namespace boost { namespace parser {
             typename SkipParser>
         auto call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -3498,7 +3498,7 @@ namespace boost { namespace parser {
             typename Attribute>
         void call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -3599,7 +3599,7 @@ namespace boost { namespace parser {
             }
 
             Iter & first_;
-            Sentinel last_;
+            Sentinel const & last_;
             Context const & context_;
             SkipParser const & skip_;
             detail::flags flags_;
@@ -3615,7 +3615,7 @@ namespace boost { namespace parser {
             typename SkipParser>
         auto call(
             Iter & first_,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -3658,7 +3658,7 @@ namespace boost { namespace parser {
             typename Attribute>
         void call(
             Iter & first_,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -3761,7 +3761,7 @@ namespace boost { namespace parser {
             int... Is>
         void call_impl(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -3857,7 +3857,7 @@ namespace boost { namespace parser {
         {
             dummy_use_parser_t(
                 Iter & first,
-                Sentinel last,
+                Sentinel const & last,
                 Context const & context,
                 SkipParser const & skip,
                 detail::flags flags,
@@ -3881,7 +3881,7 @@ namespace boost { namespace parser {
                     success_);
             }
             Iter & first_;
-            Sentinel last_;
+            Sentinel const & last_;
             Context const & context_;
             SkipParser const & skip_;
             detail::flags flags_;
@@ -4215,7 +4215,7 @@ namespace boost { namespace parser {
             typename SkipParser>
         auto make_temp_result(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -4284,7 +4284,7 @@ namespace boost { namespace parser {
             typename SkipParser>
         auto call(
             Iter & first_,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -4342,7 +4342,7 @@ namespace boost { namespace parser {
             typename Attribute>
         void call(
             Iter & first_,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -4458,7 +4458,7 @@ namespace boost { namespace parser {
             typename Merged>
         void call_impl(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -4475,7 +4475,7 @@ namespace boost { namespace parser {
                 "");
 
             auto use_parser = [&first,
-                               last,
+                               &last,
                                &context,
                                &skip,
                                flags_ = flags,
@@ -4677,7 +4677,7 @@ namespace boost { namespace parser {
             typename SkipParser>
         detail::nope call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -4696,7 +4696,7 @@ namespace boost { namespace parser {
             typename Attribute>
         void call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -4763,7 +4763,7 @@ namespace boost { namespace parser {
             typename SkipParser>
         auto call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -4787,7 +4787,7 @@ namespace boost { namespace parser {
             typename Attribute>
         void call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -4816,7 +4816,7 @@ namespace boost { namespace parser {
             typename SkipParser>
         detail::nope call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -4843,7 +4843,7 @@ namespace boost { namespace parser {
             typename Attribute>
         void call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -4875,7 +4875,7 @@ namespace boost { namespace parser {
             typename SkipParser>
         BOOST_PARSER_SUBRANGE<Iter> call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -4894,7 +4894,7 @@ namespace boost { namespace parser {
             typename Attribute>
         void call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -4931,7 +4931,7 @@ namespace boost { namespace parser {
             typename SkipParser>
         auto call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -4959,7 +4959,7 @@ namespace boost { namespace parser {
             typename Attribute>
         void call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -5014,7 +5014,7 @@ namespace boost { namespace parser {
             typename SkipParser>
         auto call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -5035,7 +5035,7 @@ namespace boost { namespace parser {
             typename Attribute>
         void call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -5068,7 +5068,7 @@ namespace boost { namespace parser {
             typename SkipParser>
         auto call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context_,
             SkipParser const & skip,
             detail::flags flags,
@@ -5092,7 +5092,7 @@ namespace boost { namespace parser {
             typename Attribute>
         void call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context_,
             SkipParser const & skip,
             detail::flags flags,
@@ -5121,7 +5121,7 @@ namespace boost { namespace parser {
             typename SkipParser_>
         auto call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser_ const & skip,
             detail::flags flags,
@@ -5142,7 +5142,7 @@ namespace boost { namespace parser {
             typename Attribute>
         void call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser_ const & skip,
             detail::flags flags,
@@ -5187,7 +5187,7 @@ namespace boost { namespace parser {
             typename SkipParser>
         detail::nope call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -5206,7 +5206,7 @@ namespace boost { namespace parser {
             typename Attribute>
         void call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -5354,7 +5354,7 @@ namespace boost { namespace parser {
             typename SkipParser>
         T call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -5373,7 +5373,7 @@ namespace boost { namespace parser {
             typename Attribute>
         void call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -5437,7 +5437,7 @@ namespace boost { namespace parser {
             attr_type>
         call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -5536,7 +5536,7 @@ namespace boost { namespace parser {
             typename Attribute_>
         void call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -5930,7 +5930,7 @@ namespace boost { namespace parser {
             typename SkipParserType>
         auto operator()(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParserType const & skip,
             detail::flags flags,
@@ -5949,7 +5949,7 @@ namespace boost { namespace parser {
             typename Attribute>
         void operator()(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParserType const & skip,
             detail::flags flags,
@@ -6263,7 +6263,7 @@ namespace boost { namespace parser {
     decltype(rule_name_)::parser_type::attr_type parse_rule(                   \
         decltype(rule_name_)::parser_type::tag_type *,                         \
         Iter & first,                                                          \
-        Sentinel last,                                                         \
+        Sentinel const & last,                                                         \
         Context const & context,                                               \
         SkipParser const & skip,                                               \
         boost::parser::detail::flags flags,                                    \
@@ -6299,7 +6299,7 @@ namespace boost { namespace parser {
     void parse_rule(                                                           \
         decltype(rule_name_)::parser_type::tag_type *,                         \
         Iter & first,                                                          \
-        Sentinel last,                                                         \
+        Sentinel const & last,                                                         \
         Context const & context,                                               \
         SkipParser const & skip,                                               \
         boost::parser::detail::flags flags,                                    \
@@ -6724,7 +6724,7 @@ namespace boost { namespace parser {
             typename SkipParser>
         detail::nope call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -6751,7 +6751,7 @@ namespace boost { namespace parser {
             typename Attribute>
         void call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -6803,7 +6803,7 @@ namespace boost { namespace parser {
             typename SkipParser>
         detail::nope call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -6824,7 +6824,7 @@ namespace boost { namespace parser {
             typename Attribute>
         void call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -6855,7 +6855,7 @@ namespace boost { namespace parser {
             typename SkipParser>
         auto call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const &,
             detail::flags flags,
@@ -6874,7 +6874,7 @@ namespace boost { namespace parser {
             typename Attribute_>
         void call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -6921,7 +6921,7 @@ namespace boost { namespace parser {
             typename SkipParser>
         auto call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -6940,7 +6940,7 @@ namespace boost { namespace parser {
             typename Attribute>
         void call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -7086,7 +7086,7 @@ namespace boost { namespace parser {
             typename SkipParser>
         auto call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -7105,7 +7105,7 @@ namespace boost { namespace parser {
             typename Attribute>
         void call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -7237,7 +7237,7 @@ namespace boost { namespace parser {
             typename SkipParser>
         auto call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -7256,7 +7256,7 @@ namespace boost { namespace parser {
             typename Attribute>
         void call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -7317,7 +7317,7 @@ namespace boost { namespace parser {
             typename SkipParser>
         auto call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -7336,7 +7336,7 @@ namespace boost { namespace parser {
             typename Attribute>
         void call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -7439,7 +7439,7 @@ namespace boost { namespace parser {
             typename SkipParser>
         std::string call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -7458,7 +7458,7 @@ namespace boost { namespace parser {
             typename Attribute>
         void call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -7603,7 +7603,7 @@ namespace boost { namespace parser {
             typename SkipParser>
         std::string call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -7622,7 +7622,7 @@ namespace boost { namespace parser {
             typename Attribute>
         void call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -7924,7 +7924,7 @@ namespace boost { namespace parser {
             typename SkipParser>
         detail::nope call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -7943,7 +7943,7 @@ namespace boost { namespace parser {
             typename Attribute>
         void call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -8091,7 +8091,7 @@ namespace boost { namespace parser {
             typename SkipParser>
         bool call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -8110,7 +8110,7 @@ namespace boost { namespace parser {
             typename Attribute>
         void call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -8180,7 +8180,7 @@ namespace boost { namespace parser {
             typename SkipParser>
         T call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -8199,7 +8199,7 @@ namespace boost { namespace parser {
             typename Attribute>
         void call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -8321,7 +8321,7 @@ namespace boost { namespace parser {
             typename SkipParser>
         T call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -8340,7 +8340,7 @@ namespace boost { namespace parser {
             typename Attribute>
         void call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -8436,7 +8436,7 @@ namespace boost { namespace parser {
             typename SkipParser>
         T call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -8455,7 +8455,7 @@ namespace boost { namespace parser {
             typename Attribute>
         void call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -8542,7 +8542,7 @@ namespace boost { namespace parser {
             typename SkipParser>
         auto call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -8570,7 +8570,7 @@ namespace boost { namespace parser {
             typename Attribute>
         void call(
             Iter & first,
-            Sentinel last,
+            Sentinel const & last,
             Context const & context,
             SkipParser const & skip,
             detail::flags flags,
@@ -9025,7 +9025,7 @@ namespace boost { namespace parser {
 #endif
     bool prefix_parse(
         I & first,
-        S last,
+        S const & last,
         parser_interface<Parser, GlobalState, ErrorHandler> const & parser,
         Attr & attr,
         trace trace_mode = trace::off)
@@ -9158,7 +9158,7 @@ namespace boost { namespace parser {
 #endif
     auto prefix_parse(
         I & first,
-        S last,
+        S const & last,
         parser_interface<Parser, GlobalState, ErrorHandler> const & parser,
         trace trace_mode = trace::off)
     {
@@ -9269,7 +9269,7 @@ namespace boost { namespace parser {
 #endif
     bool prefix_parse(
         I & first,
-        S last,
+        S const & last,
         parser_interface<Parser, GlobalState, ErrorHandler> const & parser,
         parser_interface<SkipParser> const & skip,
         Attr & attr,
@@ -9409,7 +9409,7 @@ namespace boost { namespace parser {
 #endif
     auto prefix_parse(
         I & first,
-        S last,
+        S const & last,
         parser_interface<Parser, GlobalState, ErrorHandler> const & parser,
         parser_interface<SkipParser> const & skip,
         trace trace_mode = trace::off)
@@ -9526,7 +9526,7 @@ namespace boost { namespace parser {
 #endif
     bool callback_prefix_parse(
         I & first,
-        S last,
+        S const & last,
         parser_interface<Parser, GlobalState, ErrorHandler> const & parser,
         Callbacks const & callbacks,
         trace trace_mode = trace::off)
@@ -9650,7 +9650,7 @@ namespace boost { namespace parser {
 #endif
     bool callback_prefix_parse(
         I & first,
-        S last,
+        S const & last,
         parser_interface<Parser, GlobalState, ErrorHandler> const & parser,
         parser_interface<SkipParser> const & skip,
         Callbacks const & callbacks,
@@ -9822,7 +9822,7 @@ namespace boost { namespace parser {
 
             using context = decltype(detail::make_context<false, false>(
                 std::declval<iterator>(),
-                std::declval<sentinel>(),
+                std::declval<sentinel&>(),
                 std::declval<bool &>(),
                 std::declval<int &>(),
                 std::declval<error_handler_type>(),
@@ -9831,7 +9831,7 @@ namespace boost { namespace parser {
                 std::declval<detail::pending_symbol_table_operations_t &>()));
             using type = decltype(std::declval<Parser>()(
                 std::declval<iterator &>(),
-                std::declval<sentinel>(),
+                std::declval<sentinel&>(),
                 std::declval<context>(),
                 SkipParser{},
                 detail::flags::gen_attrs,
@@ -9839,7 +9839,7 @@ namespace boost { namespace parser {
         };
 
         template<typename Iter, typename Sentinel, typename Parser>
-        auto has_attribute(Iter first, Sentinel last, Parser parser)
+        auto has_attribute(Iter first, Sentinel const & last, Parser parser)
         {
             using attr_t = typename attribute_impl<
                 BOOST_PARSER_SUBRANGE<Iter, Sentinel>,
diff --git a/include/boost/parser/parser_fwd.hpp b/include/boost/parser/parser_fwd.hpp
index 44565e88..b475cce3 100644
--- a/include/boost/parser/parser_fwd.hpp
+++ b/include/boost/parser/parser_fwd.hpp
@@ -111,7 +111,7 @@ namespace boost { namespace parser {
             typename ErrorHandler>
         inline auto make_context(
             Iter first,
-            Sentinel last,
+            Sentinel const & last,
             bool & success,
             int & indent,
             ErrorHandler const & error_handler,