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Merged
merged 7 commits into from
Feb 16, 2022
Merged

P2533R0 Core Language Working Group "ready" #5287

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e7fb089
CWG1726 Declarator operators and conversion function
jensmaurer Feb 10, 2022
a53083b
CWG2494 Multiple definitions of non-odr-used entities
jensmaurer Feb 15, 2022
bd7606c
CWG2499 Inconsistency in definition of pointer-interconvertibility
jensmaurer Feb 10, 2022
d2c8bd8
CWG2502 Unintended declaration conflicts in nested statement scopes
jensmaurer Feb 10, 2022
dc697e5
CWG2506 Structured bindings and array cv-qualifiers
jensmaurer Feb 10, 2022
0fbb2f2
CWG2509 decl-specifier-seq in lambda-specifiers
jensmaurer Feb 10, 2022
e941a31
CWG2511 cv-qualified bit-fields
jensmaurer Feb 10, 2022
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55 changes: 29 additions & 26 deletions source/basic.tex
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Expand Up @@ -329,11 +329,22 @@
\indextext{enumerator!definition}%
\indextext{one-definition rule|(}%

\pnum
Each of the following is termed a \defnadj{definable}{item}:
\begin{itemize}
\item a class type\iref{class},
\item an enumeration type\iref{dcl.enum},
\item a function\iref{dcl.fct},
\item a variable\iref{basic.pre},
\item a templated entity\iref{temp.pre},
\item a default argument for a parameter
(for a function in a given scope)\iref{dcl.fct.default}, or
\item a default template argument\iref{temp.param}.
\end{itemize}

\pnum
No translation unit shall contain more than one definition of any
variable, function, class type, enumeration type, template,
default argument for a parameter (for a function in a given scope), or
default template argument.
definable item.

\pnum
\indextext{expression!potentially evaluated}%
Expand Down Expand Up @@ -527,7 +538,7 @@
\end{example}

\pnum
Every program shall contain exactly one definition of every non-inline
Every program shall contain at least one definition of every
function or variable that is odr-used in that program
outside of a discarded statement\iref{stmt.if}; no diagnostic required.
The definition can appear explicitly in the program, it can be found in
Expand Down Expand Up @@ -611,20 +622,19 @@
\end{note}

\pnum
There can be more than one definition of a
For any definable item \tcode{D} with definitions in multiple translation units,
\begin{itemize}
\item class type\iref{class},
\item enumeration type\iref{dcl.enum},
\item inline function or variable\iref{dcl.inline},
\item templated entity\iref{temp.pre},
\item default argument for a parameter (for a function in a given scope)%
\iref{dcl.fct.default}, or
\item default template argument\iref{temp.param}
\item
if \tcode{D} is a non-inline non-templated function or variable, or
\item
if the definitions in different translation units
do not satisfy the following requirements,
\end{itemize}
in a program provided that
each definition appears in a different translation unit and
the definitions satisfy the following requirements.
Given such an entity \tcode{D} defined in more than one translation unit,
the program is ill-formed;
a diagnostic is required only
if the definable item is attached to a named module and
a prior definition is reachable at the point where a later definition occurs.
Given such an item,
for all definitions of \tcode{D}, or,
if \tcode{D} is an unnamed enumeration,
for all definitions of \tcode{D} that are reachable at any given program point,
Expand Down Expand Up @@ -745,13 +755,6 @@
might still denote different types in different translation units.
\end{note}

\pnum
If these definitions do not satisfy these requirements,
then the program is ill-formed;
a diagnostic is required only if
the entity is attached to a named module and
a prior definition is reachable at the point where a later definition occurs.

\pnum
\begin{example}
\begin{codeblock}
Expand Down Expand Up @@ -1222,7 +1225,8 @@
\grammarterm{compound-statement} of a \grammarterm{lambda-expression},
\grammarterm{function-body}, or \grammarterm{function-try-block},
\item
substatement of a selection or iteration statement, or
substatement of a selection or iteration statement
that is not itself a selection or iteration statement, or
\item
\grammarterm{handler} of a \grammarterm{function-try-block}
\end{itemize}
Expand Down Expand Up @@ -5179,8 +5183,7 @@
the other is a non-static data member of that object\iref{class.union}, or
\item
one is a standard-layout class object and
the other is the first non-static data member of that object, or,
if the object has no non-static data members,
the other is the first non-static data member of that object or
any base class subobject of that object\iref{class.mem}, or
\item
there exists an object \placeholder{c} such that
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54 changes: 43 additions & 11 deletions source/classes.tex
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Expand Up @@ -2472,8 +2472,6 @@
\indextext{fundamental type conversion|see{conversion, user-defined}}%
\indextext{conversion!user-defined}%

\pnum
A member function of a class \tcode{X} with a name of the form
\begin{bnf}
\nontermdef{conversion-function-id}\br
\keyword{operator} conversion-type-id
Expand All @@ -2488,18 +2486,52 @@
\nontermdef{conversion-declarator}\br
ptr-operator \opt{conversion-declarator}
\end{bnf}
shall have no non-object parameters and
specifies a conversion from \tcode{X} to

\pnum
A declaration
whose \grammarterm{declarator-id} has
an \grammarterm{unqualified-id} that is a \grammarterm{conversion-function-id}
declares a \defnadj{conversion}{function};
its \grammarterm{declarator} shall be
a function declarator\iref{dcl.fct} of the form
\begin{ncsimplebnf}
ptr-declarator \terminal{(} parameter-declaration-clause \terminal{)} \opt{cv-qualifier-seq}\br
\bnfindent \opt{ref-qualifier-seq} \opt{noexcept-specifier} \opt{attribute-specifier-seq}
\end{ncsimplebnf}
where the \grammarterm{ptr-declarator} consists solely of
an \grammarterm{id-expression},
an optional \grammarterm{attribute-specifier-seq}, and
optional surrounding parentheses, and
the \grammarterm{id-expression} has one of the following forms:
\begin{itemize}
\item
in a \grammarterm{member-declaration} that belongs to
the \grammarterm{member-specification} of a class or class template
but is not a friend declaration\iref{class.friend},
the \grammarterm{id-expression} is a \grammarterm{conversion-function-id};
\item
otherwise, the \grammarterm{id-expression} is a \grammarterm{qualified-id}
whose \grammarterm{unqualified-id} is a \grammarterm{conversion-function-id}.
\end{itemize}

\pnum
A conversion function shall have no non-object parameters and
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The core issue doesn't include "non-object".

I suppose you added it to account for explicit object parameters.

Is that really enough? No need to restrict it to an explicit object parameter, but any amount of non-object parameters is OK? Is there wording elsewhere that make these cases ill-formed, and thus saying "non-object" is enough?

How about the function type specified below? Does it need a revision, too?

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I think the paper misrepresents the status quo? So tihs seems like a "plausible merge".

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A conversion function with an explicit this parameter seems plausible, but there must not be other parameters. Further cleanup (if any) should be in a separate editorial or core issue.

shall be a non-static member function of a class or class template \tcode{X};
it specifies a conversion from \tcode{X} to
the type specified by the \grammarterm{conversion-type-id},
interpreted as a \grammarterm{type-id}\iref{dcl.name}.
Such functions are called \defnx{conversion functions}{conversion function}.
A \grammarterm{decl-specifier} in the \grammarterm{decl-specifier-seq}
of a conversion function (if any) shall be neither
a \grammarterm{defining-type-specifier} nor \keyword{static}.
of a conversion function (if any) shall not be
a \grammarterm{defining-type-specifier}.

\pnum
\indextext{conversion!type of}%
The type of the conversion function\iref{dcl.fct} is
``function taking no parameter returning
\grammarterm{conversion-type-id}''.
The type of the conversion function is
``\opt{\tcode{noexcept}} function taking no parameter
\opt{\grammarterm{cv-qualifier-seq}} \opt{\grammarterm{ref-qualifier}}
returning \grammarterm{conversion-type-id}''.

\pnum
A conversion function is never used to convert a (possibly cv-qualified) object
to the (possibly cv-qualified) same object type (or a reference to it),
to a (possibly cv-qualified) base class of that type (or a reference to it),
Expand Down Expand Up @@ -2783,7 +2815,7 @@
to the entity being declared.
A bit-field shall not be a static member.
\indextext{bit-field!type of}%
A bit-field shall have integral or enumeration type;
A bit-field shall have integral or (possibly cv-qualified) enumeration type;
the bit-field semantic property is not part of the type of the class member.
The \grammarterm{constant-expression} shall be an integral constant expression
with a value greater than or equal to zero and
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2 changes: 1 addition & 1 deletion source/declarations.tex
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Expand Up @@ -6714,7 +6714,7 @@
see~\ref{depr.volatile.type}.
First, a variable with a unique name \exposid{e} is introduced. If the
\grammarterm{assignment-expression} in the \grammarterm{initializer}
has array type \tcode{A} and no \grammarterm{ref-qualifier} is present,
has array type \cvqual{cv1} \tcode{A} and no \grammarterm{ref-qualifier} is present,
\exposid{e} is defined by
\begin{ncbnf}
\opt{attribute-specifier-seq} \placeholder{S} \cv{} \terminal{A} \exposid{e} \terminal{;}
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23 changes: 18 additions & 5 deletions source/expressions.tex
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Expand Up @@ -1690,7 +1690,20 @@

\begin{bnf}
\nontermdef{lambda-specifiers}\br
\opt{decl-specifier-seq} \opt{noexcept-specifier} \opt{attribute-specifier-seq} \opt{trailing-return-type}
\opt{lambda-specifier-seq} \opt{noexcept-specifier} \opt{attribute-specifier-seq} \opt{trailing-return-type}
\end{bnf}

\begin{bnf}
\nontermdef{lambda-specifier}\br
\keyword{consteval}\br
\keyword{constexpr}\br
\keyword{mutable}
\end{bnf}

\begin{bnf}
\nontermdef{lambda-specifier-seq}\br
lambda-specifier\br
lambda-specifier lambda-specifier-seq
\end{bnf}

\pnum
Expand All @@ -1715,12 +1728,12 @@
\end{note}

\pnum
In the \grammarterm{decl-specifier-seq} of the \grammarterm{lambda-declarator},
each \grammarterm{decl-specifier}
shall be one of \keyword{mutable}, \keyword{constexpr}, or \keyword{consteval}.
A \grammarterm{lambda-specifier-seq}
shall contain at most one of each \grammarterm{lambda-specifier} and
shall not contain both \keyword{constexpr} and \keyword{consteval}.
If the \grammarterm{lambda-declarator} contains
an explicit object parameter\iref{dcl.fct},
then no \grammarterm{decl-specifier} in the \grammarterm{decl-specifier-seq}
then no \grammarterm{lambda-specifier} in the \grammarterm{lambda-specifier-seq}
shall be \keyword{mutable}.
\begin{note}
The trailing \grammarterm{requires-clause} is described in \ref{dcl.decl}.
Expand Down