Empty paragraph passed to '\retval' command [-Werror,-Wdocumentation]

[matetothpal]

Summary

Compiling Mbed TLS with clang >= v15 results in compilation errors.
This is an issue similar to #7146 and #6960 but this time in library/psa_crypto_ffdh.h

System information

Mbed TLS version (current development branch (0b68784)):
Operating system and version: X86_64 Ubuntu 20.04
Configuration (if not default, please attach mbedtls_config.h): default
Compiler and options (if you used a pre-built binary, please indicate how you obtained it): llvm 15.0.6
Additional environment information: -

Expected behavior

Build successfully

Actual behavior

Build error:

In file included from library/psa_crypto.c:38:
library/psa_crypto_ffdh.h:50:41: error: empty paragraph passed to '\retval' command [-Werror,-Wdocumentation]
 * \retval #PSA_ERROR_INSUFFICIENT_MEMORY
   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
library/psa_crypto_ffdh.h:51:41: error: empty paragraph passed to '\retval' command [-Werror,-Wdocumentation]
 * \retval #PSA_ERROR_CORRUPTION_DETECTED
   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
library/psa_crypto_ffdh.h:76:35: error: empty paragraph passed to '\retval' command [-Werror,-Wdocumentation]
 * \retval #PSA_ERROR_NOT_PERMITTED
   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
...

Steps to reproduce

rm -fr build && mkdir build && pushd build && \
cmake -DCMAKE_C_COMPILER=clang .. && \
cmake --build . ; \
popd

[gilles-peskine-arm]

This specific case was fixed in #7805.

With #7968, we do a build with Clang 16 on our CI. We aren't doing a build with -Wdocumentation yet, so we aren't yet checking that other similar cases won't sneak it, but that's planned soon. So I'm closing this issue as resolved.