1791958 - (Wanon-enum-enum-conversion) Fix and re-enable C++20 -Wanon-enum-enum-conversion warnings

Status: NEW

(Firefox Build System :: General, task, P3)

Description

[Chris Peterson [:cpeterson]]

C++20 deprecates some operations between anonymous enum types:

  enum { ONE = 1 };
  enum { TWO = 2 };
  ONE | TWO;  // warning: bitwise operation between different enumeration types ('(unnamed enum at a.cpp:8:3)' and '(unnamed enum at a.cpp:9:3)') [-Wanon-enum-enum-conversion]

https://clang.llvm.org/docs/DiagnosticsReference.html#wanon-enum-enum-conversion

Comment 1

[Chris Peterson [:cpeterson]]

These -Wanon-enum-enum-conversion warnings neither block nor depend on updating to C++20 because they were downgraded from errors to warnings in bug 1781001.

Comment 2

[BugBot [:suhaib / :marco/ :calixte]]

The meta keyword is there, the bug doesn't depend on other bugs and there is no activity for 12 months.
:ahochheiden, maybe it's time to close this bug?

Comment 3

[Chris Peterson [:cpeterson]]

I removed the meta keyword for now. This meta bug is a reminder that these C++20 warnings will exist when we eventually compile with -std=c++20.

Comment 4

[Chris Peterson [:cpeterson]]

C++20 introduced these -Wanon-enum-enum-conversion warnings and C++26 made them errors:

https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2023/p2864r2.pdf