[std] Remove cross-references to the very same subclause

and add an automatic check.

Author: jensmaurer

source/classes.tex

@@ -2347,7 +2347,7 @@
 
 \pnum
 At the point of definition of a virtual destructor (including an implicit
-definition\iref{class.dtor}), the non-array deallocation function is
+definition), the non-array deallocation function is
 determined as if for the expression \tcode{delete this} appearing in a
 non-virtual destructor of the destructor's class (see~\ref{expr.delete}).
 If the lookup fails or if the deallocation function has

source/declarations.tex

@@ -3641,7 +3641,7 @@
 The invented type \grammarterm{template-parameter} is
 a template parameter pack
 if the corresponding \grammarterm{parameter-declaration}
-declares a function parameter pack\iref{dcl.fct}.
+declares a function parameter pack.
 If the placeholder contains \tcode{decltype(auto)},
 the program is ill-formed.
 The adjusted function parameters of an abbreviated function template

source/iostreams.tex

@@ -12054,7 +12054,7 @@
 \item Replace each slash character in the \grammarterm{root-name} with a \grammarterm{preferred-separator}.
 \item Replace each \grammarterm{directory-separator} with a \grammarterm{preferred-separator}.
 \begin{note}
-The generic pathname grammar\iref{fs.path.generic} defines \grammarterm{directory-separator} as one or more slashes and \grammarterm{preferred-separator}{s}.
+The generic pathname grammar defines \grammarterm{directory-separator} as one or more slashes and \grammarterm{preferred-separator}{s}.
 \end{note}
 \item Remove each dot filename and any immediately following \grammarterm{directory-separator}.
 \item As long as any appear, remove a non-dot-dot filename immediately followed by a \grammarterm{directory-separator} and a dot-dot filename, along with any immediately following \grammarterm{directory-separator}.

source/time.tex

@@ -998,7 +998,7 @@
 \pnum
 A type \tcode{TC} meets the \oldconcept{TrivialClock} requirements if:
 \begin{itemize}
-\item \tcode{TC} meets the \oldconcept{Clock} requirements\iref{time.clock.req},
+\item \tcode{TC} meets the \oldconcept{Clock} requirements,
 
 \item the types \tcode{TC::rep}, \tcode{TC::duration}, and \tcode{TC::time_point}
 meet the \oldconcept{EqualityComparable} (\tref{cpp17.equalitycomparable}) and

tools/check.sh

@@ -124,6 +124,13 @@ for f in $texlibdesc; do
     sed 's/$/ <--- \\pnum missing/'
 done | grep . && exit 1
 
+# Cross-references pointing to their own section.
+for f in $texfiles; do
+    sed -n '/^\\rSec/{s/^.rSec.\[/S /;s/\].*$//;=;p};/\\iref{/{s/^.*\\.\?ref{\([-a-z.0-9]\+\)}.*/R \1/g;=;p}' $f |
+    sed '/^[0-9]\+$/{N;s/\n/: /}' | sed "s/.*/$f:&/" |
+    awk '$2 == "S" { seclabel = $3 } $2 == "R" && $3 == seclabel { print $1 " section self-reference to [" $3 "]" }'
+done | grep . && exit 1
+
 # \placeholder before (
 #egrep 'placeholder{[-A-Za-z]*}@?\(' *.tex
 # to fix: sed -i 's/placeholder\({[-A-Za-z]*}@\?(\)/placeholdernc\1/g' *.tex