Is there any progress on this topic, now that we have Fortran 2023 as the standard for quite a while and compilers have started to support its features? I made a quick search and did not find anything newer than 2022.
My Fortran code list has a Compiler Tests section that could be helpful in creating such a list. I agree it would be nice to have. John Reid has written The new features of Fortran 2023 and similar papers for earlier standards. The code snippets there could be made compilable and tested with compilers.
Missed this list somehow. Have some of my own but not public but recently I found the best code I got out of AI so far was asking it to create unit tests for Intrinsics. Perhaps because many of the intrinsic functions are common in multiple languages and mathematical references it did a good job, but in several they seem to need reminded to test various kinds and complex types. Seems to work best just asking for one at a time.
A related issue here is the list of features to be tested. Surely one go through John Reid’s documents (up-to-date) or start with @cmaapic’s Standard Conformance Tables (AFAIU ending on F2018 and not including recent versions of gfortran). I am also considering the great LLVM Flang list of Fortran features, version by version, starting from IBM FORTRAN 704, also ending on F2018.
Do we have such a list anywhere in Fortran Wiki or Fortran Lang pages? If not, could it be added and updated?
Then we could probably start preparing the tests. I’d vote to do it backwards, as the most recent features are more likely not supported yet.
That looks like a nice project 
I still have a fairly large set of test programs at flibs - a collection of Fortran modules / SVN / [r429] /trunk/chkfeatures. I have not worked on them for some years now, as other things drew my attention, so the latest standard is definitely not covered. Perhaps I should revive it via github …