Merge 2022-07 LWG Motion 36

P2549R1 std::unexpected<E> should have error() as member accessor

Author: tkoeppe

source/utilities.tex

@@ -6929,10 +6929,10 @@
     constexpr unexpected& operator=(const unexpected&) = default;
     constexpr unexpected& operator=(unexpected&&) = default;
 
-    constexpr const E& value() const & noexcept;
-    constexpr E& value() & noexcept;
-    constexpr const E&& value() const && noexcept;
-    constexpr E&& value() && noexcept;
+    constexpr const E& error() const & noexcept;
+    constexpr E& error() & noexcept;
+    constexpr const E&& error() const && noexcept;
+    constexpr E&& error() && noexcept;
 
     constexpr void swap(unexpected& other) noexcept(@\seebelow@);
 
@@ -6942,7 +6942,7 @@
     friend constexpr void swap(unexpected& x, unexpected& y) noexcept(noexcept(x.swap(y)));
 
   private:
-    E @\exposid{val}@;               // \expos
+    E @\exposidnc{unex}@;             // \expos
   };
 
   template<class E> unexpected(E) -> unexpected<E>;
@@ -6979,11 +6979,11 @@
 
 \pnum
 \effects
-Direct-non-list-initializes \exposid{val} with \tcode{std::forward<Err>(e)}.
+Direct-non-list-initializes \exposid{unex} with \tcode{std::forward<Err>(e)}.
 
 \pnum
 \throws
-Any exception thrown by the initialization of \exposid{val}.
+Any exception thrown by the initialization of \exposid{unex}.
 \end{itemdescr}
 
 \indexlibraryctor{unexpected}%
@@ -7000,11 +7000,11 @@
 \pnum
 \effects
 Direct-non-list-initializes
-\exposid{val} with \tcode{std::forward<Args>(args)...}.
+\exposid{unex} with \tcode{std::forward<Args>(args)...}.
 
 \pnum
 \throws
-Any exception thrown by the initialization of \exposid{val}.
+Any exception thrown by the initialization of \exposid{unex}.
 \end{itemdescr}
 
 \indexlibraryctor{unexpected}%
@@ -7021,37 +7021,37 @@
 \pnum
 \effects
 Direct-non-list-initializes
-\exposid{val} with \tcode{il, std::forward<Args>(args)...}.
+\exposid{unex} with \tcode{il, std::forward<Args>(args)...}.
 
 \pnum
 \throws
-Any exception thrown by the initialization of \exposid{val}.
+Any exception thrown by the initialization of \exposid{unex}.
 \end{itemdescr}
 
 \rSec3[expected.un.obs]{Observers}
 
-\indexlibrarymember{value}{unexpected}%
+\indexlibrarymember{error}{unexpected}%
 \begin{itemdecl}
-constexpr const E& value() const & noexcept;
-constexpr E& value() & noexcept;
+constexpr const E& error() const & noexcept;
+constexpr E& error() & noexcept;
 \end{itemdecl}
 
 \begin{itemdescr}
 \pnum
 \returns
-\exposid{val}.
+\exposid{unex}.
 \end{itemdescr}
 
-\indexlibrarymember{value}{unexpected}%
+\indexlibrarymember{error}{unexpected}%
 \begin{itemdecl}
-constexpr E&& value() && noexcept;
-constexpr const E&& value() const && noexcept;
+constexpr E&& error() && noexcept;
+constexpr const E&& error() const && noexcept;
 \end{itemdecl}
 
 \begin{itemdescr}
 \pnum
 \returns
-\tcode{std::move(\exposid{val})}.
+\tcode{std::move(\exposid{unex})}.
 \end{itemdescr}
 
 \rSec3[expected.un.swap]{Swap}
@@ -7069,7 +7069,7 @@
 \pnum
 \effects
 Equivalent to:
-\tcode{using std::swap; swap(\exposid{val}, other.\exposid{val});}
+\tcode{using std::swap; swap(\exposid{unex}, other.\exposid{unex});}
 \end{itemdescr}
 
 \begin{itemdecl}
@@ -7097,12 +7097,12 @@
 \begin{itemdescr}
 \pnum
 \mandates
-The expression \tcode{x.value() == y.value()} is well-formed and
+The expression \tcode{x.error() == y.error()} is well-formed and
 its result is convertible to \tcode{bool}.
 
 \pnum
 \returns
-\tcode{x.value() == y.value()}.
+\tcode{x.error() == y.error()}.
 \end{itemdescr}
 
 \rSec2[expected.bad]{Class template \tcode{bad_expected_access}}
@@ -7120,7 +7120,7 @@
     E&& error() && noexcept;
     const E&& error() const && noexcept;
   private:
-    E @\exposid{val}@;              // \expos
+    E @\exposidnc{unex}@;             // \expos
   };
 }
 \end{codeblock}
@@ -7139,7 +7139,7 @@
 \begin{itemdescr}
 \pnum
 \effects
-Initializes \exposid{val} with \tcode{std::move(e)}.
+Initializes \exposid{unex} with \tcode{std::move(e)}.
 \end{itemdescr}
 
 \indexlibrarymember{error}{bad_expected_access}%
@@ -7151,7 +7151,7 @@
 \begin{itemdescr}
 \pnum
 \returns
-\exposid{val}.
+\exposid{unex}.
 \end{itemdescr}
 
 \indexlibrarymember{error}{bad_expected_access}%
@@ -7163,7 +7163,7 @@
 \begin{itemdescr}
 \pnum
 \returns
-\tcode{std::move(\exposid{val})}.
+\tcode{std::move(\exposid{unex})}.
 \end{itemdescr}
 
 \indexlibrarymember{what}{bad_expected_access}%
@@ -7575,7 +7575,7 @@
 
 \pnum
 \effects
-Direct-non-list-initializes \exposid{unex} with \tcode{std::forward<GF>(e.value())}.
+Direct-non-list-initializes \exposid{unex} with \tcode{std::forward<GF>(e.error())}.
 
 \pnum
 \ensures
@@ -7905,12 +7905,12 @@
 \item
 If \tcode{has_value()} is \tcode{true}, equivalent to:
 \begin{codeblock}
-@\exposid{reinit-expected}@(@\exposid{unex}@, @\exposid{val}@, std::forward<GF>(e.value()));
+@\exposid{reinit-expected}@(@\exposid{unex}@, @\exposid{val}@, std::forward<GF>(e.error()));
 @\exposid{has_val}@ = false;
 \end{codeblock}
 \item
 Otherwise, equivalent to:
-\tcode{\exposid{unex} = std::forward<GF>(e.value());}
+\tcode{\exposid{unex} = std::forward<GF>(e.error());}
 \end{itemize}
 
 \pnum
@@ -8270,12 +8270,12 @@
 \begin{itemdescr}
 \pnum
 \mandates
-The expression \tcode{x.error() == e.value()} is well-formed and
+The expression \tcode{x.error() == e.error()} is well-formed and
 its result is convertible to \tcode{bool}.
 
 \pnum
 \returns
-\tcode{!x.has_value() \&\& static_cast<bool>(x.error() == e.value())}.
+\tcode{!x.has_value() \&\& static_cast<bool>(x.error() == e.error())}.
 \end{itemdescr}
 
 \rSec2[expected.void]{Partial specialization of \tcode{expected} for \tcode{void} types}
@@ -8516,7 +8516,7 @@
 \pnum
 \effects
 Direct-non-list-initializes \exposid{unex}
-with \tcode{std::forward<GF>(e.value())}.
+with \tcode{std::forward<GF>(e.error())}.
 
 \pnum
 \ensures
@@ -8703,12 +8703,12 @@
 \item
 If \tcode{has_value()} is \tcode{true}, equivalent to:
 \begin{codeblock}
-construct_at(addressof(@\exposid{unex}@), std::forward<GF>(e.value()));
+construct_at(addressof(@\exposid{unex}@), std::forward<GF>(e.error()));
 @\exposid{has_val}@ = false;
 \end{codeblock}
 \item
 Otherwise, equivalent to:
-\tcode{\exposid{unex} = std::forward<GF>(e.value());}
+\tcode{\exposid{unex} = std::forward<GF>(e.error());}
 \end{itemize}
 
 \pnum
@@ -8897,12 +8897,12 @@
 \begin{itemdescr}
 \pnum
 \mandates
-The expression \tcode{x.error() == e.value()} is well-formed and
+The expression \tcode{x.error() == e.error()} is well-formed and
 its result is convertible to \tcode{bool}.
 
 \pnum
 \returns
-\tcode{!x.has_value() \&\& static_cast<bool>(x.error() == e.value())}.
+\tcode{!x.has_value() \&\& static_cast<bool>(x.error() == e.error())}.
 \end{itemdescr}
 
 \rSec1[bitset]{Bitsets}