CWG2586 Explicit object parameter for assignment and comparison

Author: burblebee

source/classes.tex

@@ -1678,7 +1678,7 @@
 \indextext{operator!move assignment|see{assignment operator, move}}%
 A user-declared \term{copy} assignment operator \tcode{X::operator=} is a
 non-static non-template member function of class \tcode{X} with exactly one
-parameter of type \tcode{X}, \tcode{X\&}, \tcode{const X\&},
+non-object parameter of type \tcode{X}, \tcode{X\&}, \tcode{const X\&},
 \tcode{volatile X\&}, or \tcode{const volatile X\&}.
 \begin{footnote}
 Because
@@ -1763,7 +1763,7 @@
 \pnum
 A user-declared move assignment operator \tcode{X::operator=} is
 a non-static non-template member function of class \tcode{X} with exactly
-one parameter of type \tcode{X\&\&}, \tcode{const X\&\&}, \tcode{volatile X\&\&}, or
+one non-object parameter of type \tcode{X\&\&}, \tcode{const X\&\&}, \tcode{volatile X\&\&}, or
 \tcode{const volatile X\&\&}.
 \begin{note}
 An overloaded assignment operator must be
@@ -6457,15 +6457,14 @@
 that is
 \begin{itemize}
 \item
-a non-static const non-volatile member of \tcode{C} having
-one parameter of type \tcode{const C\&} and either
-no \grammarterm{ref-qualifier} or
-the \grammarterm{ref-qualifier} \tcode{\&}, or
+a non-static member or friend of \tcode{C} and
 
 \item
-a friend of \tcode{C} having either
+either has
 two parameters of type \tcode{const C\&} or
-two parameters of type \tcode{C}.
+two parameters of type \tcode{C},
+where the implicit object parameter (if any) is considered to be
+the first parameter.
 \end{itemize}
 A comparison operator function for class \tcode{C} that
 is defaulted on its first declaration and

source/declarations.tex

@@ -6211,28 +6211,38 @@
 \end{itemize}
 
 \pnum
-The type \tcode{T}$_1$ of an explicitly defaulted special member function \tcode{F}
-is allowed to differ from the type \tcode{T}$_2$ it would have had
-if it were implicitly declared, as follows:
+An explicitly defaulted special member function $\tcode{F}_1$
+with type $\tcode{T}_1$
+is allowed to differ from
+the corresponding special member function $\tcode{F}_2$
+with type $\tcode{T}_2$
+that would have been implicitly declared, as follows:
 \begin{itemize}
 \item
-  \tcode{T}$_1$ and \tcode{T}$_2$ may have differing \grammarterm{ref-qualifier}{s};
+  $\tcode{T}_1$ and $\tcode{T}_2$ may have differing \grammarterm{ref-qualifier}{s};
 \item
-  \tcode{T}$_1$ and \tcode{T}$_2$ may have differing exception specifications; and
+  if $\tcode{F}_2$ has an implicit object parameter of
+  type ``reference to \tcode{C}'',
+  $\tcode{F}_1$ may be an explicit object member function whose
+  explicit object parameter is of type ``reference to \tcode{C}'';
 \item
-  if \tcode{T}$_2$ has a parameter of type \tcode{const C\&},
-  the corresponding parameter of \tcode{T}$_1$ may be of type \tcode{C\&}.
+  $\tcode{T}_1$ and $\tcode{T}_2$ may have differing exception specifications; and
+\item
+  if $\tcode{F}_2$ has a non-object parameter of type \tcode{const C\&},
+  the corresponding non-object parameter of $\tcode{F}_1$ may be of
+  type \tcode{C\&}.
 \end{itemize}
-If \tcode{T}$_1$ differs from \tcode{T}$_2$ in any other way, then:
+If $\tcode{T}_1$ differs from $\tcode{T}_2$ in a way
+other than as allowed by the preceding rules, then:
 \begin{itemize}
 \item
-  if \tcode{F} is an assignment operator, and
-  the return type of \tcode{T}$_1$ differs from
-  the return type of \tcode{T}$_2$ or
-  \tcode{T}$_1${'s} parameter type is not a reference,
+  if $\tcode{F}_1$ is an assignment operator, and
+  the return type of $\tcode{T}_1$ differs from
+  the return type of $\tcode{T}_2$ or
+  $\tcode{F}_1${'s} non-object parameter type is not a reference,
   the program is ill-formed;
 \item
-  otherwise, if \tcode{F} is explicitly defaulted on its first declaration,
+  otherwise, if $\tcode{F}_1$ is explicitly defaulted on its first declaration,
   it is defined as deleted;
 \item
   otherwise, the program is ill-formed.