Anonymous links to sections create extra labels in LaTeX output

[cpitclaudel]

Describe the bug

Using a target in an anonymous link causes sphinx to define the target twice:

This is a test:

- `xyz`__, this is an anonymous link

__ target_

Some text

.. _target:

Some more text

Output with Sphinx:

This is a test:
\begin{itemize}
\item {} 
{\hyperref[\detokenize{index:target}]{\sphinxcrossref{xyz}}}, this is an anonymous link

\end{itemize}
\phantomsection\label{\detokenize{index:target}}\phantomsection\label{\detokenize{index:id1}}
Some text

\phantomsection\label{\detokenize{index:target}}
Some more text

Output with rst2latex:

This is a test:

\begin{itemize}
\item \hyperref[target]{xyz}, this is an anonymous link
\end{itemize}

Some text

\phantomsection\label{target}
Some more text

The Sphinx one has Label `index:target' multiply defined

Expected behavior

Sphinx shouldn't define the label twice.

Environment info

• OS: GNU/Linux
• Python version: 3.6.9
• Sphinx version: 2.3.1
• Sphinx extensions: none
• Extra tools: LaTeX

Btw, could there be a sphinx command to get all this info? Like sphinx-build --version could print the OS, python version, and sphinx version, and even installed extensions.

Thanks!