Merge 2019-07 CWG Motion 24

P1703R1 Recognizing header unit imports requires full preprocessing

Fixes #3003.

Author: zygoloid

source/basic.tex

@@ -815,9 +815,12 @@
 
 \rSec2[basic.scope.pdecl]{Point of declaration}
 
+\indextext{declaration!point of|(}%
+
 \pnum
-\indextext{name!point of declaration}%
-The \defn{point of declaration} for a name is immediately after its
+\indextext{name!point of declaration|see{declaration, point of}}%
+\indextext{point of!declaration|see{declaration, point of}}%
+The \defnx{point of declaration}{declaration!point of} for a name is immediately after its
 complete declarator\iref{dcl.decl} and before its
 \grammarterm{initializer} (if any), except as noted below. \begin{example}
 
@@ -963,9 +966,11 @@
 \end{note}
 
 \pnum
-\begin{note} For point of instantiation of a template,
-see~\ref{temp.point}.\end{note}%
+\begin{note}
+For point of instantiation of a template, see~\ref{temp.point}.
+\end{note}
 \indextext{scope!declarations and|)}
+\indextext{declaration!point of|)}
 
 \rSec2[basic.scope.block]{Block scope}
 
@@ -2590,8 +2595,7 @@
 
 \pnum
 A token sequence beginning with
-\opt{\tcode{export}} \tcode{module} or
-\opt{\tcode{export}} \tcode{import}
+\opt{\tcode{export}} \tcode{module}
 and not immediately followed by \tcode{::}
 is never interpreted as the \grammarterm{declaration}
 of a \grammarterm{top-level-declaration}.

source/lex.tex

@@ -273,6 +273,7 @@
 \begin{bnf}
 \nontermdef{preprocessing-token}\br
     header-name\br
+    import-keyword\br
     identifier\br
     pp-number\br
     character-literal\br
@@ -338,17 +339,13 @@
 except that a \grammarterm{header-name}\iref{lex.header} is only formed
 \begin{itemize}
 \item
-within a \tcode{\#include} directive\iref{cpp.include},
+after the \tcode{include} or \tcode{import} preprocessing token in an
+\tcode{\#include}\iref{cpp.include} or
+\tcode{import}\iref{cpp.import} directive, or
 
 \item
-within a \grammarterm{has-include-expression}, or
+within a \grammarterm{has-include-expression}.
 
-\item
-outside of any preprocessing directive,
-if applying phase 4 of translation to the sequence
-of preprocessing tokens produced thus far
-is valid and
-results in an \grammarterm{import-seq}\iref{cpp.module}.
 \end{itemize}
 \end{itemize}
 
@@ -359,6 +356,11 @@
 \end{codeblock}
 \end{example}
 
+\pnum
+The \grammarterm{import-keyword} is produced
+by processing an \tcode{import} directive\iref{cpp.import} and
+has no associated grammar productions.
+
 \pnum
 \begin{example} The program fragment \tcode{0xe+foo} is parsed as a
 preprocessing number token (one that is not a valid floating or integer

source/modules.tex

@@ -411,9 +411,9 @@
 
 \begin{bnf}
 \nontermdef{module-import-declaration}\br
-    \opt{\keyword{export}} \keyword{import} module-name \opt{attribute-specifier-seq} \terminal{;}\br
-    \opt{\keyword{export}} \keyword{import} module-partition \opt{attribute-specifier-seq} \terminal{;}\br
-    \opt{\keyword{export}} \keyword{import} header-name \opt{attribute-specifier-seq} \terminal{;}
+    \opt{\keyword{export}} import-keyword module-name \opt{attribute-specifier-seq} \terminal{;}\br
+    \opt{\keyword{export}} import-keyword module-partition \opt{attribute-specifier-seq} \terminal{;}\br
+    \opt{\keyword{export}} import-keyword header-name \opt{attribute-specifier-seq} \terminal{;}
 \end{bnf}
 
 \pnum
@@ -478,7 +478,7 @@
 a \grammarterm{header-name} is also recognized by the
 preprocessor, and results in macros defined at the
 end of phase 4 of translation of the header unit
-being made visible as described in \ref{cpp.module}.
+being made visible as described in \ref{cpp.import}.
 \end{note}
 A declaration of a name with internal linkage is
 permitted within a header unit despite all