CWG3093 Missing integration of direct base class relationships

Fixes NB US 27-059 (C++26 CD).

Author: eisenwave

source/basic.tex

@@ -405,8 +405,9 @@
 an array operand, the set contains the potential results of that operand.
 \item If $E$ is a class member access
 expression\iref{expr.ref} of the form
-$E_1$ \tcode{.} \opt{\keyword{template}} $E_2$
-naming a non-static data member,
+$E_1$ \tcode{.} \opt{\keyword{template}} $E_2$,
+where $E_2$ designates a a non-static data member or
+a direct base class relationship,
 the set contains the potential results of $E_1$.
 \item If $E$ is a class member access expression
 naming a static data member,

source/expressions.tex

@@ -147,7 +147,10 @@
 \end{importgraphic}
 
 \begin{itemize}
-\item A \defn{glvalue} is an expression whose evaluation determines the identity of an object, function, or non-static data member.
+\item A \defn{glvalue} is an expression
+whose evaluation determines the identity of
+an object, function, non-static data member, or
+a direct base class relationship.
 \item A \defn{prvalue} is an expression whose evaluation initializes an object
 or computes the value of an operand of an operator,
 as specified by the context in which it appears,
@@ -1487,6 +1490,10 @@
 \end{example}
 \end{itemize}
 
+\pnum
+A \grammarterm{splice-expression} that designates a direct base class relationship
+shall appear only as the second operand of a class member access.
+
 \pnum
 For an \grammarterm{id-expression} that denotes an overload set,
 overload resolution is performed
@@ -3598,6 +3605,10 @@
 does not apply to a \grammarterm{splice-expression}.
 \end{note}
 \item
+Otherwise, if $S$ is a direct base class relationship $(\tcode{D}, \tcode{B})$,
+the expression is an lvalue designating $S$.
+The expression has the type \tcode{B}.
+\item
 Otherwise, if $S$ is a variable or a structured binding,
 $S$ shall either have static or thread storage duration or
 shall inhabit a scope enclosing the expression.
@@ -4362,7 +4373,8 @@
 
 \pnum
 If \tcode{E2} designates a non-static member
-(possibly after overload resolution) and
+(possibly after overload resolution)
+or direct base class relationship and
 the result of \tcode{E1} is an object whose type
 is not similar\iref{conv.qual} to the type of \tcode{E1},
 the behavior is undefined.

source/overloading.tex

@@ -3693,6 +3693,15 @@
 \begin{ncsimplebnf}
 \terminal{(} postfix-expression . \keyword{operator} \terminal{->} \terminal{(}\terminal{)} \terminal{)} \terminal{->} \opt{\keyword{template}} id-expression
 \end{ncsimplebnf}
+Analogously, for an expression of the form
+\begin{ncsimplebnf}
+postfix-expression \terminal{->} splice-expression
+\end{ncsimplebnf}
+the operator function is selected by overload resolution,
+and the expression is interpreted as
+\begin{ncsimplebnf}
+\terminal{(} postfix-expression . \keyword{operator} \terminal{->} \terminal{(}\terminal{)} \terminal{)} \terminal{->} splice-expression
+\end{ncsimplebnf}
 
 \rSec2[over.inc]{Increment and decrement}
 \indextext{increment operator!overloaded|see{overloading, increment operator}}%

source/templates.tex

@@ -5874,9 +5874,15 @@
 \pnum
 A class member access expression\iref{expr.ref} is
 type-dependent if
-the terminal name of its \grammarterm{id-expression}, if any, is dependent or
+\begin{itemize}
+\item
+the terminal name of its \grammarterm{id-expression}, if any, is dependent,
+\item
+its \grammarterm{splice-expression}, if any, is type-dependent, or
+\item
 the expression refers to a member of the current instantiation and
 the type of the referenced member is dependent.
+\end{itemize}
 \begin{note}
 In an expression of the form
 \tcode{x.y}