Merge 2020-11 CWG Motion 3

P2096R2 Generalized wording for partial specializations

Author: tkoeppe

source/classes.tex

@@ -60,7 +60,7 @@
 A class declaration where the \grammarterm{class-name}
 in the \grammarterm{class-head-name} is a \grammarterm{simple-template-id}
 shall be an explicit specialization\iref{temp.expl.spec} or
-a partial specialization\iref{temp.class.spec}.
+a partial specialization\iref{temp.spec.partial}.
 A \grammarterm{class-specifier} whose
 \grammarterm{class-head} omits the
 \grammarterm{class-head-name} defines an unnamed class.

source/declarations.tex

@@ -7192,7 +7192,7 @@
 namespace is implicitly inserted into the enclosing namespace as for an unnamed
 namespace\iref{namespace.unnamed}. Furthermore, each
 member of the inline namespace can subsequently be partially
-specialized\iref{temp.class.spec}, explicitly
+specialized\iref{temp.spec.partial}, explicitly
 instantiated\iref{temp.explicit}, or explicitly specialized\iref{temp.expl.spec} as
 though it were a member of the enclosing namespace. Finally, looking up a name in the
 enclosing namespace via explicit qualification\iref{namespace.qual} will include
@@ -7893,7 +7893,7 @@
 considered when a use of the name is made. Thus, additional
 overloads added after the \grammarterm{using-declaration} are ignored, but
 default function arguments\iref{dcl.fct.default}, default template
-arguments\iref{temp.param}, and template specializations~(\ref{temp.class.spec},
+arguments\iref{temp.param}, and template specializations~(\ref{temp.spec.partial},
 \ref{temp.expl.spec}) are considered.
 \end{note}
 \begin{example}
@@ -7920,12 +7920,12 @@
 
 \pnum
 \begin{note}
-Partial specializations of class templates are found by looking up the
-primary class template and then considering all partial specializations
-of that template. If a \grammarterm{using-declaration} names a class
+Partial specializations of templates are found by looking up the
+primary template and then considering all partial specializations
+of that template. If a \grammarterm{using-declaration} names a
 template, partial specializations introduced after the
 \grammarterm{using-declaration} are effectively visible because the primary
-template is visible\iref{temp.class.spec}.
+template is visible\iref{temp.spec.partial}.
 \end{note}
 
 \pnum

source/templates.tex

@@ -119,11 +119,11 @@
 \begin{note}
 That last component can be an \grammarterm{identifier}, an \grammarterm{operator-function-id},
 a \grammarterm{conversion-function-id}, or a \grammarterm{literal-operator-id}. In
-a class template declaration, if the
-class name
+a class or variable template declaration, if the
+declared name
 is a
 \grammarterm{simple-template-id},
-the declaration declares a class template partial specialization\iref{temp.class.spec}.
+the declaration declares a partial specialization\iref{temp.spec.partial}.
 \end{note}
 
 \pnum
@@ -142,8 +142,8 @@
 a template that has internal linkage are
 distinct from all specializations in other translation
 units.
-A template, a template explicit specialization\iref{temp.expl.spec}, and a class
-template partial specialization shall not have C linkage. Use of a linkage specification
+A template, an explicit specialization\iref{temp.expl.spec}, and a
+partial specialization shall not have C linkage. Use of a linkage specification
 other than \tcode{"C"} or \tcode{"C++"} with any of these constructs is
 conditionally-supported, with
 \impldef{semantics of linkage specification on templates} semantics.
@@ -157,7 +157,7 @@
 \pnum
 A class template shall not have the same name as any other
 template, class, function, variable, enumeration, enumerator, namespace, or
-type in the same scope\iref{basic.scope}, except as specified in~\ref{temp.class.spec}.
+type in the same scope\iref{basic.scope}, except as specified in~\ref{temp.spec.partial}.
 Except that a function template can be overloaded either by non-template
 functions\iref{dcl.fct} with the same name or by other function templates
 with the same name\iref{temp.over},
@@ -1315,15 +1315,14 @@
 \grammarterm{template-parameter}
 shall be the name of a class template or an alias template, expressed as
 \grammarterm{id-expression}.
-When the \grammarterm{template-argument} names a class
-template, only primary class templates are considered when matching the template template
+Only primary templates are considered when matching the template template
 argument with the corresponding parameter; partial specializations are not
 considered even if their parameter lists match that of the template template
 parameter.
 
 \pnum
-Any partial specializations\iref{temp.class.spec} associated with the
-primary class template or primary variable template are considered when a
+Any partial specializations\iref{temp.spec.partial} associated with the
+primary template are considered when a
 specialization based on the template
 \grammarterm{template-parameter}
 is instantiated.
@@ -1992,7 +1991,7 @@
 \item the best viable candidate of non-template functions\iref{over.match.best},
 \item the address of a non-template function\iref{over.over},
 \item the matching of template template arguments\iref{temp.arg.template},
-\item the partial ordering of class template specializations\iref{temp.class.order}, and
+\item the partial ordering of class template specializations\iref{temp.spec.partial.order}, and
 \item the partial ordering of function templates\iref{temp.func.order}.
 \end{itemize}
 \end{note}
@@ -2163,21 +2162,10 @@
 \rSec2[temp.decls.general]{General}
 
 \pnum
-A
-\grammarterm{template-id},
-that is, the
-\grammarterm{template-name}
-followed by a
-\grammarterm{template-argument-list}
-shall not be specified in the declaration of a primary template declaration.
-\begin{example}
-\begin{codeblock}
-template<class T1, class T2, int I> class A<T1, T2, I> { };     // error
-template<class T1, int I> void sort<T1, I>(T1 data[I]);         // error
-\end{codeblock}
-\end{example}
 \begin{note}
-However, this syntax is allowed in class template partial specializations\iref{temp.class.spec}.
+A \grammarterm{template-id}
+cannot be the declared name of a primary template declaration.
+However, this syntax is allowed in partial specializations\iref{temp.spec.partial}.
 \end{note}
 
 \pnum
@@ -3079,7 +3067,7 @@
 \pnum
 A template friend declaration specifies that all specializations of that
 template, whether they are implicitly instantiated\iref{temp.inst}, partially
-specialized\iref{temp.class.spec} or explicitly specialized\iref{temp.expl.spec},
+specialized\iref{temp.spec.partial} or explicitly specialized\iref{temp.expl.spec},
 are friends of the class containing the template friend declaration.
 \begin{example}
 \begin{codeblock}
@@ -3183,38 +3171,34 @@
 Such a constrained friend function or function template declaration
 does not declare the same function or function template as a declaration in any other scope.
 
-\rSec2[temp.class.spec]{Class template partial specializations}
+\rSec2[temp.spec.partial]{Partial specialization}
 
-\rSec3[temp.class.spec.general]{General}
+\rSec3[temp.spec.partial.general]{General}
 
 \pnum
 \indextext{specialization!class template partial}%
 \indextext{primary class template|see{template, primary}}%
-A
-\defnx{primary class template}{template!primary}
-declaration is one in which the class template name is an
-identifier.
-A template declaration in which the class template name is a
+A \defnadj{primary}{template} declaration
+is one in which the name of the template
+is not followed by a \grammarterm{template-argument-list}.
+A template declaration in which the template name is a
 \grammarterm{simple-template-id}
-is a
-\defnx{partial specialization}{specialization!class template partial}
-of the class template named in the
-\grammarterm{simple-template-id}.
-A partial specialization of a class template provides an alternative definition
+is a \defnadj{partial}{specialization}
+of the template named in the \grammarterm{simple-template-id},
+which shall be a class or variable template.
+A partial specialization of a template provides an alternative definition
 of the template that is used instead of the primary definition when the
 arguments in a specialization match those given in the partial
-specialization\iref{temp.class.spec.match}.
-The primary template shall be declared before any specializations of
+specialization\iref{temp.spec.partial.match}.
+The primary template shall be declared before any partial specializations of
 that template.
-A partial specialization shall be declared before the first use of a class template
+A partial specialization shall be declared before the first use of a template
 specialization that would make use of the partial specialization as the result of
 an implicit or explicit instantiation in every translation unit in which such a use
 occurs; no diagnostic is required.
 
 \pnum
-Each class template partial specialization is a distinct template and
-definitions shall be provided for the members of a template partial
-specialization\iref{temp.class.spec.mfunc}.
+Each partial specialization is a distinct template.
 
 \pnum
 \begin{example}
@@ -3232,7 +3216,7 @@
 \end{example}
 
 \pnum
-A class template partial specialization may be constrained\iref{temp.pre}.
+A partial specialization may be constrained\iref{temp.constr}.
 \begin{example}
 \begin{codeblock}
 template<typename T> concept C = true;
@@ -3250,15 +3234,12 @@
 \end{example}
 
 \pnum
-The template parameters are specified in the angle bracket enclosed list
-that immediately follows the keyword
-\keyword{template}.
+The template parameters of a template are specified in the angle bracket enclosed list
+that immediately follows the keyword \keyword{template}.
 For partial specializations, the template argument list is explicitly
-written immediately following the class template name.
+written immediately following the template name.
 For primary templates, this list is implicitly described by the
-template parameter list.
-Specifically, the order of the template arguments is the sequence in
-which they appear in the template parameter list.
+template parameter list\iref{temp.dep.type}.
 \begin{example}
 The template argument list for the primary template in the example
 above is
@@ -3278,7 +3259,7 @@
 \end{note}
 
 \pnum
-A class template partial specialization may be declared in any
+A partial specialization may be declared in any
 scope in which the corresponding primary template
 may be defined~(\ref{namespace.memdef}, \ref{class.mem}, \ref{temp.mem}).
 \begin{example}
@@ -3302,12 +3283,12 @@
 Partial specialization declarations themselves are not found by name lookup.
 Rather, when the primary template name is used, any previously-declared partial
 specializations of the primary template are also considered.
+\begin{note}
 One consequence is
-that a
-\grammarterm{using-declaration}
+that a \grammarterm{using-declaration}
 which refers to a class template does not restrict the set of partial specializations
-which may be found through the
-\grammarterm{using-declaration}.
+that are found through the \grammarterm{using-declaration}.
+\end{note}
 \begin{example}
 \begin{codeblock}
 namespace N {
@@ -3331,13 +3312,13 @@
 All other non-type arguments are specialized.
 
 \pnum
-Within the argument list of a class template partial specialization,
+Within the argument list of a partial specialization,
 the following restrictions apply:
 
 \begin{itemize}
 \item
 The type of a template parameter corresponding to a specialized non-type argument
-shall not be dependent on a parameter of the specialization.
+shall not be dependent on a parameter of the partial specialization.
 \begin{example}
 \begin{codeblock}
 template <class T, T t> struct C {};
@@ -3350,11 +3331,11 @@
 
 \end{example}
 \item
-The specialization shall be more specialized than the primary
-template\iref{temp.class.order}.
+The partial specialization shall be more specialized than the primary
+template\iref{temp.spec.partial.order}.
 
 \item
-The template parameter list of a specialization shall not contain default
+The template parameter list of a partial specialization shall not contain default
 template argument values.
 \begin{footnote}
 There is no context in which they would be used.
@@ -3376,29 +3357,29 @@
 but will be checked when substituting into the partial specialization.
 \end{note}
 
-\rSec3[temp.class.spec.match]{Matching of class template partial specializations}
+\rSec3[temp.spec.partial.match]{Matching of partial specializations}
 
 \pnum
-When a class template is used in a context that requires an instantiation of
-the class,
+When a template is used in a context that requires an instantiation of
+the template,
 it is necessary to determine whether the instantiation is to be generated
 using the primary template or one of the partial specializations.
-This is done by matching the template arguments of the class template
+This is done by matching the template arguments of the template
 specialization with the template argument lists of the partial
 specializations.
 
 \begin{itemize}
 \item
-If exactly one matching specialization is found, the instantiation is
-generated from that specialization.
+If exactly one matching partial specialization is found, the instantiation is
+generated from that partial specialization.
 \item
-If more than one matching specialization is found,
-the partial order rules\iref{temp.class.order} are used to determine
-whether one of the specializations is more specialized than the
+If more than one matching partial specialization is found,
+the partial order rules\iref{temp.spec.partial.order} are used to determine
+whether one of the partial specializations is more specialized than the
 others.
-If none of the specializations is more specialized than all of the
-other matching specializations, then the use of the class template
-is ambiguous and the program is ill-formed.
+If such a partial specialization exists,
+the instantiation is generated from that partial specialization;
+otherwise, the use of the template is ambiguous and the program is ill-formed.
 \item
 If no matches are found, the instantiation is generated from the
 primary template.
@@ -3457,18 +3438,18 @@
 \end{example}
 
 \pnum
-In a type name that refers to a class template specialization, (e.g.,
-\tcode{A<int, int, 1>})
+In a name that refers to a specialization of a class or variable template
+(e.g., \tcode{A<int, int, 1>}),
 the argument list shall match the template parameter list of the primary
 template.
-The template arguments of a specialization are deduced from the arguments
+The template arguments of a partial specialization are deduced from the arguments
 of the primary template.
 
-\rSec3[temp.class.order]{Partial ordering of class template specializations}
+\rSec3[temp.spec.partial.order]{Partial ordering of partial specializations}
 
 \pnum
 \indextext{more specialized!class template}%
-For two class template partial specializations,
+For two partial specializations,
 the first is \defn{more specialized} than the second if, given the following
 rewrite to two function templates, the first function template is more
 specialized than the second according to the ordering rules for function
@@ -3540,7 +3521,7 @@
 because \tcode{B} is more specialized than \tcode{A}.
 \end{example}
 
-\rSec3[temp.class.spec.mfunc]{Members of class template specializations}
+\rSec3[temp.spec.partial.member]{Members of class template partial specializations}
 
 \pnum
 The template parameter list of a member of a class template partial
@@ -3549,7 +3530,6 @@
 The template argument list of a member of a class template partial
 specialization shall match the template argument list of the class template
 partial specialization.
-A class template partial specialization is a distinct template.
 The members of the class template partial specialization are
 unrelated to the members of the primary template.
 Class template partial specialization members that are used in a way that
@@ -3558,7 +3538,7 @@
 template partial specialization.
 An explicit specialization of a member of a class template partial
 specialization is declared in the same way as an explicit specialization of
-the primary template.
+a member of the primary template.
 \begin{example}
 \begin{codeblock}
 // primary class template
@@ -4289,7 +4269,7 @@
 A concept cannot be
 explicitly instantiated\iref{temp.explicit},
 explicitly specialized\iref{temp.expl.spec},
-or partially specialized.
+or partially specialized\iref{temp.spec.partial}.
 \end{note}
 
 \pnum
@@ -5072,8 +5052,8 @@
 the name of the nested class referenced as a member of the
 current instantiation, or
 \item
-in the definition of a partial specialization
-or a member of a partial specialization, the name of
+in the definition of a class template partial specialization
+or a member of a class template partial specialization, the name of
 the class template followed by the template argument list of
 the partial specialization enclosed in
 \tcode{<>} (or an equivalent template alias specialization).