P0758R1 Implicit conversion traits and utility functions

Author: jensmaurer

source/utilities.tex

@@ -15321,6 +15321,7 @@
 
 \rSec2[meta.type.synop]{Header \tcode{<type_traits>} synopsis}
 
+\indexlibrary{\idxcode{is_nothrow_convertible_v}}%
 \indexhdr{type_traits}%
 \begin{codeblock}
 namespace std {
@@ -15423,6 +15424,7 @@
   template<class T, class U> struct is_same;
   template<class Base, class Derived> struct is_base_of;
   template<class From, class To> struct is_convertible;
+  template<class From, class To> struct is_nothrow_convertible;
 
   template<class Fn, class... ArgTypes> struct is_invocable;
   template<class R, class Fn, class... ArgTypes> struct is_invocable_r;
@@ -15693,6 +15695,8 @@
     inline constexpr bool is_base_of_v = is_base_of<Base, Derived>::value;
   template<class From, class To>
     inline constexpr bool is_convertible_v = is_convertible<From, To>::value;
+  template<class From, class To>
+    inline constexpr bool is_nothrow_convertible_v = is_nothrow_convertible<From, To>::value;
   template<class Fn, class... ArgTypes>
     inline constexpr bool is_invocable_v = is_invocable<Fn, ArgTypes...>::value;
   template<class R, class Fn, class... ArgTypes>
@@ -16500,6 +16504,16 @@
  types, arrays of unknown
  bound, or \cv{}~\tcode{void} types.                \\ \rowsep
 
+\indexlibrary{\idxcode{is_nothrow_convertible}}%
+\tcode{template<class From, class To>}\br
+ \tcode{struct is_nothrow_convertible;}     &
+ \tcode{is_convertible_v<From, To>} is \tcode{true} and
+ the conversion, as defined by \tcode{is_convertible},
+ is known not to throw any exceptions\iref{expr.unary.noexcept} &
+ \tcode{From} and \tcode{To} shall be complete
+ types, arrays of unknown
+ bound, or \cv{}~\tcode{void} types.                \\ \rowsep
+
 \indexlibrary{\idxcode{is_invocable}}%
 \tcode{template<class Fn, class... ArgTypes>}\br
  \tcode{struct is_invocable;}                      &