[variant.variant] Placeholder FUN

Also addresses #693.

Author: tkoeppe

source/utilities.tex

@@ -4281,8 +4281,8 @@
 \begin{itemdescr}
 \pnum
 Let \tcode{T}$_j$ be a type that is determined as follows:
-build an imaginary function \tcode{\textit{FUN}(\tcode{T}$_i$)} for each alternative type \tcode{T}$_i$. The overload \tcode{\textit{FUN}(\tcode{T}$_j$)} selected by overload
-resolution for the expression \tcode{\textit{FUN}(std::forward<T>(\brk{}t))} defines
+build an imaginary function \tcode{\placeholdernc{FUN}(\tcode{T}$_i$)} for each alternative type \tcode{T}$_i$. The overload \tcode{\placeholdernc{FUN}(\tcode{T}$_j$)} selected by overload
+resolution for the expression \tcode{\placeholdernc{FUN}(std::forward<T>(\brk{}t))} defines
 the alternative \tcode{T}$_j$ which is the type of the contained value after
 construction.
 
@@ -4309,7 +4309,7 @@
 nor a specialization of \tcode{in_place_index_t},
 unless \tcode{is_constructible_v<T$_j$, T>} is \tcode{true},
 and unless the expression
-\tcode{\textit{FUN}(}\brk\tcode{std::forward<T>(t))} (with \tcode{\textit{FUN}}
+\tcode{\placeholdernc{FUN}(}\brk\tcode{std::forward<T>(t))} (with \tcode{\placeholdernc{FUN}}
 being the above-mentioned set of imaginary functions) is well formed.
 
 \pnum
@@ -4589,9 +4589,9 @@
 \begin{itemdescr}
 \pnum
 Let \tcode{T}$_j$ be a type that is determined as follows:
-build an imaginary function \tcode{\textit{FUN}(T$_i$)} for each alternative type
-\tcode{T}$_i$. The overload \tcode{\textit{FUN}(T$_j$)} selected by overload
-resolution for the expression \tcode{\textit{FUN}(std::forward<T>(\brk{}t))} defines
+build an imaginary function \tcode{\placeholdernc{FUN}(T$_i$)} for each alternative type
+\tcode{T}$_i$. The overload \tcode{\placeholdernc{FUN}(T$_j$)} selected by overload
+resolution for the expression \tcode{\placeholdernc{FUN}(std::forward<T>(\brk{}t))} defines
 the alternative \tcode{T}$_j$ which is the type of the contained value after
 assignment.
 
@@ -4617,8 +4617,8 @@
 This function shall not participate in overload resolution unless
 \tcode{is_same_v<decay_t<T>, variant>} is \tcode{false}, unless
 \tcode{is_assignable_v<T$_j$\&, T> \&\& is_constructible_v<T$_j$, T>} is \tcode{true},
-and unless the expression \tcode{\textit{FUN}(std::forward<T>(t))} (with
-\tcode{\textit{FUN}} being the above-mentioned set of imaginary functions)
+and unless the expression \tcode{\placeholdernc{FUN}(std::forward<T>(t))} (with
+\tcode{\placeholdernc{FUN}} being the above-mentioned set of imaginary functions)
 is well formed.
 
 \pnum
@@ -4632,7 +4632,9 @@
 
 \pnum
 The expression inside \tcode{noexcept} is equivalent to:
-\tcode{is_nothrow_assignable_v<T$_j$\&, T> \&\& is_nothrow_constructible_v<T$_j$, T>}.
+\begin{codeblock}
+is_nothrow_assignable_v<T@$_j$@&, T> && is_nothrow_constructible_v<T@$_j$@, T>
+\end{codeblock}
 \begin{itemize}
 \item If an exception is thrown during the assignment of \tcode{std::forward<T>(t)}
 to the value contained in \tcode{*this}, the state of the contained value and