How to identify trailing types in the XML output? #11568

ilg-ul · 2025-05-12T08:51:33Z

ilg-ul
May 12, 2025

I have the following definition:

template <class T>
[[nodiscard]] constexpr auto
mut (const T& t) noexcept -> T&
{
  return const_cast<T&> (t);
}

It is correctly rendered as:

The generated xml is:

      <memberdef kind="function" id="namespacemicro__os__plus_1_1micro__test__plus_1a00ea8f3dfb7cb0ef39919065321cf62f" prot="public" static="no" nodiscard="yes" constexpr="yes" const="no" explicit="no" inline="no" noexcept="yes" virt="non-virtual">
        <templateparamlist>
          <param>
            <type>class T</type>
          </param>
        </templateparamlist>
        <type>T &amp;</type>
        <definition>T &amp; micro_os_plus::micro_test_plus::mut</definition>
        <argsstring>(const T &amp;t) noexcept</argsstring>
        <name>mut</name>
        <qualifiedname>micro_os_plus::micro_test_plus::mut</qualifiedname>
        <param>
          <type>const T &amp;</type>
          <declname>t</declname>
        </param>
        <briefdescription>
<para>Generic mutator, to remove const from any type. </para>
        </briefdescription>
        <detaileddescription>
        </detaileddescription>
        <inbodydescription>
        </inbodydescription>
        <location file="/Users/ilg/MyProjects/micro-os-plus.github/xPacks/micro-test-plus-xpack.git/include/micro-os-plus/micro-test-plus.h" line="483" column="3" bodyfile="/Users/ilg/MyProjects/micro-os-plus.github/xPacks/micro-test-plus-xpack.git/include/micro-os-plus/micro-test-plus.h" bodystart="483" bodyend="486"/>
      </memberdef>

The question is how to identify in the XML output that this is a trailing type and render it correctly?

I guess we need an additional attribute, like trailingtype="yes".

albert-github · 2025-05-12T12:18:12Z

albert-github
May 12, 2025
Collaborator

To be able to say more the small code snippet as not enough, as I don't see e.g. the word mut at all in the code.

Can you please attach a, small, self contained example (source+configuration file in a, compressed, tar or zip file!) that allows us to reproduce the question?
Please don't add external links as they might not be persistent (also references to GitHub repositories are considered non persistent).
Please also specify the full doxygen version used (doxygen -v). It looks like you are using doxygen 1.13.2

2 replies

ilg-ul May 12, 2025
Author

as I don't see e.g. the word mut at all in the code

oops! a small copy/paste issue. I added it.

I can prepare an archive, but the point is not to reproduce any bug. It is a question related to rendering definitions with trailing types (the auto before the name and the -> T& following the arguments).

More specifically, a notice that the information defining a type as trailing is not passed in the XML.

Unless I missed something, the XML fragment above should be enough to confirm this. I could not find any attribute or element to indicate that the type is trailing. Without this information, a third party post-processor which gets the input from the XML, would render this as:

template <class T>
[[nodiscard]] constexpr T&
mut (const T& t) noexcept
{
  return const_cast<T&> (t);
}

i.e. no auto and no ->.

Is this information enough to confirm the problem?

It looks like you are using doxygen 1.13.2

That's correct.

albert-github May 12, 2025
Collaborator

I know it is about a question, but as it looks like there is some information missing in the XML result it would be good that we could reproduce the situation and when it is not intended we can make advise to make an issue or straight away fix it.
Sp all in all yes please create an archive with the relevant information as indicated before.

ilg-ul · 2025-05-12T13:34:03Z

ilg-ul
May 12, 2025
Author

please create an archive

Here it is:

trailing-type-issue.zip

Please let me know if you need further information.

0 replies

albert-github · 2025-05-12T14:45:11Z

albert-github
May 12, 2025
Collaborator

Indeed the information that it is a trailing type doesn't look like to be present in the xml file. In the HTML output we see for mut:

<tr>
          <td class="memname">auto mut </td>
          <td>(</td>
          <td class="paramtype">const T &amp;</td>          <td class="paramname"><span class="paramname"><em>t</em></span></td><td>)</td>
          <td> -&gt; T&amp;
</td>
        </tr>

so here it looks like there is some information present in the doxygen internal information.
@doxygen how to proceed?

2 replies

ilg-ul May 12, 2025
Author

From my point of view, adding a new attribute to <memberdef> would be enough to render these cases correctly.

ilg-ul Jun 25, 2025
Author

Any progress on this?

Provide feedback

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