add testfile for phantom issue

required/latex-lab/math-tagging-issues/phantom.tex

@@ -0,0 +1,67 @@
+\DocumentMetadata{uncompress,testphase=latest,pdfversion=2.0}
+\documentclass{article}
+\usepackage{unicode-math}
+\tagpdfsetup{math/mathml/structelem}
+\begin{document}
+
+% lots of warning about structures without parent,
+% wrong output
+%abc $x_1^2 \mathstrut_1^2 \vphantom{\int}_1^2  $
+
+
+\makeatletter\ExplSyntaxOn
+\sys_if_engine_luatex:T
+{
+\def\ph@nt#1{%
+  \ifmmode
+    \ifcase\mathstyle
+      \mathph@nt\displaystyle{#1}\or
+      \mathph@nt\displaystyle{#1}\or
+      \mathph@nt\textstyle{#1}\or
+      \mathph@nt\textstyle{#1}\or
+      \mathph@nt\scriptstyle{#1}\or
+      \mathph@nt\scriptstyle{#1}\or
+      \mathph@nt\scriptscriptstyle{#1}\or
+      \mathph@nt\scriptscriptstyle{#1}\or
+    \fi 
+  \else
+    \expandafter\makeph@nt
+  \fi}
+
+\cs_set:Npn \mathph@nt #1 #2 {%
+ %
+  \setbox \z@ = \hbox {
+    $
+    \m@th
+    #1
+    {\SuspendTagging{phantom}#2}
+    \luamml_save:nNn {mathphant} #1 {mphantom}
+    $
+  } 
+  \luamml_annotate:nen {1} {
+    nucleus = true,
+    core = {[0] = 'mpadded',
+      \ifh@\else
+        width = 0,
+      \fi
+      \ifv@\else
+        height = 0, depth = 0,
+      \fi
+      consume_label'mathphant',
+    }
+  } {
+    \finph@nt
+  }
+   % 
+}
+}
+\ExplSyntaxOff
+
+abc $x_1^2 \mathstrut_1^2 \vphantom{\int}_1^2  $
+
+%$ \vphantom{x\mathstrut} $ gives
+% Package tagpdf Warning: structure with label 20 has already been used
+% and faulty structure
+
+
+\end{document}