Merge 2022-07 LWG Motion 15

Author: tkoeppe

source/support.tex

@@ -591,6 +591,7 @@
 #define @\defnlibxname{cpp_lib_complex_udls}@                      201309L // also in \libheader{complex}
 #define @\defnlibxname{cpp_lib_concepts}@                          202002L // also in \libheader{concepts}
 #define @\defnlibxname{cpp_lib_constexpr_algorithms}@              201806L // also in \libheader{algorithm}
+#define @\defnlibxname{cpp_lib_constexpr_charconv}@                202207L // also in \libheader{charconv}
 #define @\defnlibxname{cpp_lib_constexpr_cmath}@                   202202L // also in \libheader{cmath}, \libheader{cstdlib}
 #define @\defnlibxname{cpp_lib_constexpr_complex}@                 201711L // also in \libheader{complex}
 #define @\defnlibxname{cpp_lib_constexpr_dynamic_alloc}@           201907L // also in \libheader{memory}

source/utilities.tex

@@ -13401,7 +13401,7 @@
     friend bool operator==(const to_chars_result&, const to_chars_result&) = default;
   };
 
-  to_chars_result to_chars(char* first, char* last, @\placeholder{integer-type}@ value, int base = 10);
+  constexpr to_chars_result to_chars(char* first, char* last, @\placeholder{integer-type}@ value, int base = 10);
   to_chars_result to_chars(char* first, char* last, bool value, int base = 10) = delete;
 
   to_chars_result to_chars(char* first, char* last, @\placeholder{floating-point-type}@ value);
@@ -13420,8 +13420,8 @@
     friend bool operator==(const from_chars_result&, const from_chars_result&) = default;
   };
 
-  from_chars_result from_chars(const char* first, const char* last,
-                               @\placeholder{integer-type}@& value, int base = 10);
+  constexpr from_chars_result from_chars(const char* first, const char* last,
+                                         @\placeholder{integer-type}@& value, int base = 10);
 
   from_chars_result from_chars(const char* first, const char* last, @\placeholder{floating-point-type}@& value,
                                chars_format fmt = chars_format::general);
@@ -13490,7 +13490,7 @@
 
 \indexlibraryglobal{to_chars}%
 \begin{itemdecl}
-to_chars_result to_chars(char* first, char* last, @\placeholder{integer-type}@ value, int base = 10);
+constexpr to_chars_result to_chars(char* first, char* last, @\placeholder{integer-type}@ value, int base = 10);
 \end{itemdecl}
 
 \begin{itemdescr}
@@ -13621,8 +13621,8 @@
 
 \indexlibraryglobal{from_chars}%
 \begin{itemdecl}
-from_chars_result from_chars(const char* first, const char* last,
-                             @\placeholder{integer-type}@&@\itcorr[-1]@ value, int base = 10);
+constexpr from_chars_result from_chars(const char* first, const char* last,
+                                       @\placeholder{integer-type}@&@\itcorr[-1]@ value, int base = 10);
 \end{itemdecl}
 
 \begin{itemdescr}