cppdialect is not set for Xcode project

[cos-public]

What seems to be the problem?
cppdialect c++latest is not set for Xcode project.
Setting c++20 or c++2a fails with:
Error: invalid value 'c++20' for cppdialect

What have you tried so far?
Setting C++ Language Dialect from Xcode IDE works fine

How can we reproduce this?
Run premake5 xcode4 on any project with cppdialect property and look for grep -e "CLANG_CXX_LANGUAGE_STANDARD" project.pbxproj

What version of Premake are you using?
premake5 (Premake Build Script Generator) 5.0.0-alpha15
Xcode Version 11.7 (11E801a)

[cos-public]

And a follow-up documentation issue: https://github.com/premake/premake-core/wiki/cppdialect seems outdated since #1460 was merged

[cos-public]

It seems that #1460 is not included in the recent release on github (though it was merged 3 months ago), so probably the issue can be closed for now.
However I still cannot set anything higher than c++17 on macos even on latest trunk.

[samsinsane]

though it was merged 3 months ago

I don't understand what point you're trying to make here? Latest release was 5 months ago, so it's impossible to have those changes in it?

However I still cannot set anything higher than c++17 on macos even on latest trunk.

Sounds like you're on a commit before that PR, can you confirm that you're on 670935a?

[cos-public]

though it was merged 3 months ago

I don't understand what point you're trying to make here? Latest release was 5 months ago, so it's impossible to have those changes in it?

Sorry, no implications there. I just wish to have some kind of nightly builds to use recent important features.

However I still cannot set anything higher than c++17 on macos even on latest trunk.

Sounds like you're on a commit before that PR, can you confirm that you're on 670935a?

I've did my best to check that I'm on the latest version of master. And the behaviour is different from alpha15 version. premake5 is no longer gives an error about unrecognised c++2a or c++20 option. It just doesn't set any 'C++ Language Dialect' value. Hope someone could check this independently.

[samsinsane]

I just wish to have some kind of nightly builds to use recent important features.

Here is the latest master build, with the artifacts uploaded. You'll need to keep track of the version information, or keep up with master, if you're going to report issues about it though as we don't embed any build info into the binary.

It just doesn't set any 'C++ Language Dialect' value. Hope someone could check this independently.

Using latest, I get the following in the project file output:

CLANG_CXX_LANGUAGE_STANDARD = "c++2a";

Without seeing your script there's not much help I can provide here, you'll just need to check that you're not calling cppdialect again afterwards, or calling removeflags { "C++11" } or removeflags { "C++14" } as both of these will call cppdialect "Default", or check that it's not within a filter or within the right filter and that you've spelt everything correctly in the filter. I can't really think of anything else that would cause this to happen.

[cos-public]

Here is the latest master build, with the artifacts uploaded. You'll need to keep track of the version information, or keep up with master, if you're going to report issues about it though as we don't embed any build info into the binary.
Thank you.
Using latest, I get the following in the project file output:

CLANG_CXX_LANGUAGE_STANDARD = "c++2a";

That was my fault. The option c++20 works indeed and sets the flag /std:c++2a for clang using current nightly build.
However I would like to kindly ask you to support c++2a option for Xcode as well to avoid such pitfall. As c++2a is currently supported (according to #1460) but silently ignored for Xcode. But option c++20 sets c++2a compiler flag.

[nickclark2016]

I'll handle this one