diff --git a/include/boost/url/impl/url_base.ipp b/include/boost/url/impl/url_base.ipp
index c65eab0e..cf6b0765 100644
--- a/include/boost/url/impl/url_base.ipp
+++ b/include/boost/url/impl/url_base.ipp
@@ -2242,11 +2242,12 @@ edit_params(
 
 //------------------------------------------------
 
+template<class CharSet>
 void
 url_base::
 normalize_octets_impl(
     int id,
-    grammar::lut_chars const& cs,
+    CharSet const& allowed,
     op_t& op) noexcept
 {
     char* it = s_ + u_.offset(id);
@@ -2270,7 +2271,7 @@ normalize_octets_impl(
             &buf,
             &buf + 1,
             string_view(it, 3));
-        if (cs(buf))
+        if (allowed(buf))
         {
             *dest = buf;
             it += 3;
diff --git a/include/boost/url/url_base.hpp b/include/boost/url/url_base.hpp
index c17b9491..55a9f1ba 100644
--- a/include/boost/url/url_base.hpp
+++ b/include/boost/url/url_base.hpp
@@ -36,9 +36,6 @@ struct any_segments_iter;
 struct params_iter_impl;
 struct segments_iter_impl;
 }
-namespace grammar {
-class lut_chars;
-}
 #endif
 
 /** Common functionality for containers
@@ -2607,8 +2604,9 @@ private:
         url_view_base const& base,
         url_view_base const& ref);
 
+    template<class CharSet>
     void normalize_octets_impl(int,
-        grammar::lut_chars const& cs, op_t&) noexcept;
+        CharSet const& allowed, op_t&) noexcept;
     void decoded_to_lower_impl(int id) noexcept;
     void to_lower_impl(int id) noexcept;
 };