Explicit labels on code blocks are duplicated in LaTeX output

[cpitclaudel]

Problem

The following snippet causes laTeX to complain about multiply-defined labels:

.. _test:

.. code:: python

   pass

This is low-priority, because using a proper :name: annotation works fine:

.. code:: python
   :name: test

   pass

(But it's still an issue when one wants to place an anchor before a list of multiple code samples.)

Error logs / results

Latexmk: List of undefined refs and citations:
  Label `index:test' multiply defined
Latexmk: Summary of warnings:
  Latex found 1 multiply defined reference(s)

Environment info

• OS: GNU/Linux
• Python version: 3.5.2
• Sphinx version: 1.7.4

[tk0miya]

Fixed by #4982.
Thank you for reporting!