"Invalid C++ declaration" with C++ lambda expression

[pitrou]

Describe the bug

When building the Apache Arrow docs, we get the following warning:

/home/antoine/arrow/dev/docs/source/cpp/api/dataset.rst:62: WARNING: Parsing of expression failed. Using fallback parser. Error was:
Error in postfix expression, expected primary expression or type.
If primary expression:
  Invalid C++ declaration: Expected identifier in nested name. [error at 59]
    std::function< Status(FileWriter *)> writer_pre_finish   = [](FileWriter*) {returnStatus::OK();}
    -----------------------------------------------------------^
If type:
  Invalid C++ declaration: Expected identifier in nested name. [error at 59]
    std::function< Status(FileWriter *)> writer_pre_finish   = [](FileWriter*) {returnStatus::OK();}
    -----------------------------------------------------------^

How to Reproduce

The build procedure is a bit too complex to reproduce here. But I don't think that matters since the context is clear from the warning message above.

Expected behavior

Ideally there's a way to silence the warning. I understand that parsing C++ is hard, so I'm not necessarily expecting Sphinx to get it right in all cases :-) But the warning is distracting.

Your project

https://arrow.apache.org/

Screenshots

No response

OS

Ubuntu 20.04

Python version

3.9.7

Sphinx version

4.3.2

Sphinx extensions

breathe 4.31.0

Extra tools

doxygen 1.9.2

Additional context

No response

[drewrisinger]

Bump. Ran into this error today