Hello everyone,

I recently noticed that there is no way to attach C++ attributes to concepts introduced in C++20. More precisely, the C++ grammar doesn't have any placeholder for starting an attribute specifier sequence. In practice, this means that you cannot deprecate a concept using the [[deprecated]] attribute introduced in C++14 for instance. It also means that you cannot really extend that new C++ feature using custom attributes. Apparently this limitation of the language has been discovered by other people and it feels that this could have been an oversight from the committee when integrating concepts to the language.

I was considering to report this problem as a standard issue but I would like to seek
advice here first:

I would really appreciate some help here.

Sincerely,
Jean Guegant