I noticed Ubuntu Lunar 23.04 ships with flang-new-16 from the llvm 16.0.0 release as well as the prior flang-new-15 from the llvm 15.0.0 release neither of which appears to compile fortran source code into executables. Is there a schedule yet with a tentative release by which flang will actually be useful to end users?
You could try
As @tschuett pointed out, that flag will let you see it works with your code, but there are still some things not implemented, and of course the occasional bug. You can look at the project board and todo list for a summary of the status.