P0702R1 Language support for Constructor Template Argument Deduction

Reverse order of "For each constructor of C, if C is defined," to
"If C is defined, for each constructor of C," for clarity and to
parallel adjacent "If C is not defined" bullet.

Author: Dawn Perchik

source/overloading.tex

@@ -1387,33 +1387,31 @@
 \indextext{deduction!class template arguments}%
 
 \pnum
-A set of functions and function templates is formed comprising:
-
+When resolving a placeholder for a deduced class type~(\ref{dcl.type.class.deduct})
+where the \grammarterm{template-name} names a primary class template \tcode{C},
+a set of functions and function templates is formed comprising:
 \begin{itemize}
 \item
-For each constructor
-of the primary class template
-designated by the \grammarterm{template-name},
-if the template is defined,
+If \tcode{C} is defined,
+for each constructor of \tcode{C},
 a function template with the following properties:
 \begin{itemize}
 \item
-The template parameters are the template parameters of the class template
+The template parameters are the template parameters of \tcode{C}
 followed
 by the template parameters (including default template arguments) of the constructor,
 if any.
 \item
 The types of the function parameters are those of the constructor.
 \item
 The return type is the class template specialization
-designated by the \grammarterm{template-name}
+designated by \tcode{C}
 and template arguments
-corresponding to the template parameters
-obtained from the class template.
+corresponding to the template parameters of \tcode{C}.
 \end{itemize}
 
 \item
-If the primary class template \tcode{C}
+If \tcode{C}
 is not defined or does not declare any constructors,
 an additional function template derived as above
 from a hypothetical constructor \tcode{C()}.
@@ -1448,7 +1446,14 @@
 the selected functions and function templates are considered to be the
 constructors of that class type for the purpose of forming an overload
 set, and the initializer is provided by the context in which class
-template argument deduction was performed. Each such notional constructor
+template argument deduction was performed.
+As an exception, the first phase in \ref{over.match.list}
+(considering initializer-list constructors)
+is omitted if the initializer list consists of
+a single expression of type \cv{}~\tcode{U},
+where \tcode{U} is a specialization of \tcode{C} or
+a class derived from a specialization of \tcode{C}.
+Each such notional constructor
 is considered to be explicit if the function or function template was
 generated from a constructor or \grammarterm{deduction-guide} that was
 declared \tcode{explicit}.