P3923R0: Re NB US 227-346 and US 229-347 (C++26 CD)

Fixes NB US 227-346 and US 229-347 (C++26 CD).

Author: eisenwave

source/exec.tex

@@ -5385,17 +5385,18 @@
     void @\exposid{abandon}@() noexcept;                                                // \expos
 
   private:
-    using @\exposid{alloc-t}@ =                                                         // \expos
-      allocator_traits<Alloc>::template rebind_alloc<@\exposid{spawn-future-state}@>;
-
-    @\exposid{alloc-t}@ @\exposid{alloc}@;                                                          // \expos
+    Alloc @\exposid{alloc}@;                                                            // \expos
     @\exposid{ssource-t}@ @\exposid{ssource}@;                                                      // \expos
     @\exposid{op-t}@ @\exposid{op}@;                                                                // \expos
     Token @\exposid{token}@;                                                            // \expos
     bool @\exposid{associated}@;                                                        // \expos
 
     void @\exposid{destroy}@() noexcept;                                                // \expos
   };
+
+  template<class Alloc, @\libconcept{scope_token}@ Token, @\libconcept{sender}@ Sender, class Env>        // \expos
+    @\exposid{spawn-future-state}@(Alloc alloc, Sender&& sndr, Token token, Env env)
+      -> @\exposid{spawn-future-state}@<Alloc, Token, Sender, Env>;
 }
 \end{codeblock}
 
@@ -5498,10 +5499,10 @@
 bool associated = this->@\exposid{associated}@;
 
 {
-  auto alloc = std::move(this->@\exposid{alloc}@);
-
-  allocator_traits<@\exposid{alloc-t}@>::destroy(alloc, this);
-  allocator_traits<@\exposid{alloc-t}@>::deallocate(alloc, this, 1);
+  using traits = allocator_traits<Alloc>::template rebind_traits<@\exposid{spawn-future-state}@>;
+  typename traits::allocator_type alloc(std::move(this->@\exposid{alloc}@));
+  traits::destroy(alloc, this);
+  traits::deallocate(alloc, this, 1);
 }
 
 if (associated)
@@ -5559,8 +5560,8 @@
 
 \begin{itemize}
 \item
-Uses \tcode{alloc} to allocate and construct an object \tcode{s} of
-a type that is a specialization of \exposid{spawn-future-\brk{}state}
+Uses \tcode{alloc} to allocate and construct an object \tcode{s} of type
+\tcode{decltype(\exposid{spawn-future-state}(alloc, token.wrap(sndr), token, senv))}
 from \tcode{alloc}, \tcode{token.wrap(sndr)}, \tcode{token}, and \tcode{senv}.
 If an exception is thrown then
 any constructed objects are destroyed and
@@ -5900,10 +5901,7 @@
     void @\exposid{run}@();                                             // \expos
 
   private:
-    using @\exposid{alloc-t}@ =                                         // \expos
-      allocator_traits<Alloc>::template rebind_alloc<@\exposid{spawn-state}@>;
-
-    @\exposid{alloc-t}@ @\exposid{alloc}@;                                          // \expos
+    Alloc @\exposid{alloc}@;                                            // \expos
     @\exposid{op-t}@ @\exposid{op}@;                                                // \expos
     Token @\exposid{token}@;                                            // \expos
 
@@ -5973,10 +5971,10 @@
 \effects
 Equivalent to:
 \begin{codeblock}
-auto alloc = std::move(this->@\exposid{alloc}@);
-
-allocator_traits<@\exposid{alloc-t}@>::destroy(alloc, this);
-allocator_traits<@\exposid{alloc-t}@>::deallocate(alloc, this, 1);
+using traits = allocator_traits<Alloc>::template rebind_traits<@\exposid{spawn-state}@>;
+typename traits::allocator_type alloc(std::move(this->@\exposid{alloc}@));
+traits::destroy(alloc, this);
+traits::deallocate(alloc, this, 1);
 \end{codeblock}
 \end{itemdescr}
 
@@ -6006,9 +6004,9 @@
 %%FIXME: Was this supposed to be more than a single bullet?
 \begin{itemize}
 \item
-Uses \tcode{alloc} to allocate and construct an object \tcode{o} of
-type that is a specialization of \tcode{\exposid{spawn-state}} from
-\tcode{alloc}, \tcode{write_env(token.wrap(sndr), senv)}, and \tcode{token}
+Uses \tcode{alloc} to allocate and construct an object \tcode{o} of type
+\tcode{decltype(\exposid{spawn-state}(alloc, write_env(token.wrap(sndr), senv), token))}
+from \tcode{alloc}, \tcode{write_env(token.wrap(sndr), senv)}, and \tcode{token}
 and then
 invokes \tcode{o.\exposid{run}()}.
 If an exception is thrown then