LWG3483 transform_view::iterator's difference is overconstrained

Author: burblebee

source/ranges.tex

@@ -3814,7 +3814,7 @@
     friend constexpr @\exposid{iterator}@ operator-(@\exposid{iterator}@ i, difference_type n)
       requires @\libconcept{random_access_range}@<@\exposid{Base}@>;
     friend constexpr difference_type operator-(const @\exposid{iterator}@& x, const @\exposid{iterator}@& y)
-      requires @\libconcept{random_access_range}@<@\exposid{Base}@>;
+      requires @\libconcept{sized_sentinel_for}@<iterator_t<@\exposid{Base}@>, iterator_t<@\exposid{Base}@>>;
 
     friend constexpr decltype(auto) iter_move(const @\exposid{iterator}@& i)
       noexcept(noexcept(invoke(*i.@\exposid{parent_}@->@\exposid{fun_}@, *i.@\exposid{current_}@)))
@@ -4123,7 +4123,7 @@
 \indexlibrarymember{operator-}{transform_view::iterator}%
 \begin{itemdecl}
 friend constexpr difference_type operator-(const @\exposid{iterator}@& x, const @\exposid{iterator}@& y)
-  requires @\libconcept{random_access_range}@<@\exposid{Base}@>;
+  requires @\libconcept{sized_sentinel_for}@<iterator_t<@\exposid{Base}@>, iterator_t<@\exposid{Base}@>>;
 \end{itemdecl}
 
 \begin{itemdescr}
@@ -6441,7 +6441,7 @@
     friend constexpr @\exposid{iterator}@ operator-(const @\exposid{iterator}@& x, difference_type y)
       requires @\libconcept{random_access_range}@<@\exposid{Base}@>;
     friend constexpr difference_type operator-(const @\exposid{iterator}@& x, const @\exposid{iterator}@& y)
-      requires @\libconcept{random_access_range}@<@\exposid{Base}@>;
+      requires @\libconcept{sized_sentinel_for}@<iterator_t<@\exposid{Base}@>, iterator_t<@\exposid{Base}@>>;
   };
 }
 \end{codeblock}
@@ -6708,7 +6708,7 @@
 \indexlibrarymember{operator-}{elements_view::iterator}%
 \begin{itemdecl}
 friend constexpr difference_type operator-(const @\exposid{iterator}@& x, const @\exposid{iterator}@& y)
-  requires @\libconcept{random_access_range}@<@\exposid{Base}@>;
+  requires @\libconcept{sized_sentinel_for}@<iterator_t<@\exposid{Base}@>, iterator_t<@\exposid{Base}@>>;
 \end{itemdecl}
 
 \begin{itemdescr}