internal compiler error with gcc-7.3.1 about toml11

[ToruNiina]

Hi @patrikhuber , I have a good news, possibly.

I tried Manjaro by using VirtualBox, and reproduced the error you told.

I simplified SFINAE stuffs in toml::get and some other related functions, and now (b1a55b1), the errors disappeared. It compiles fine with gcc-7.3.1, and all the tests passes (at least on my VM).

Please try it.
Thank you for using this product.

[patrikhuber]

Our repo's CI is happy! (clang-5, g++-7 (Ubuntu), Xcode 9.2). Thank you so much again for the quick fix! :>

[patrikhuber]

Hmm, I'm actually not 100% sure about this bug.
It compiles fine on g++-7 (Ubuntu 7.3.0-16ubuntu3~16.04.1) 7.3.0.
But it gives an ICE on c++ (GCC) 7.3.1 20180312 (Manjaro).

So this could be either a regression in g++-7.3.1 or a problem with Manjaro/arch's g++ build...

[patrikhuber]

I've submitted a bug report on the arch bug-tracker https://bugs.archlinux.org/task/58406, let's see.
Edit: It seems like the arch people are not really interested in an ICE bug report, it got closed right away. Doesn't seem the most friendly environment :-/
Maybe you've got some other ideas what we could do :-)

[ToruNiina]

Hi, thank you for telling me about this problem.
I tried to reproduce the error, but I couldn't find gcc 7.3.1 in the release page https://gcc.gnu.org/gcc-7/ . Is it arch-specific version?
I also confirmed that g++-7.3.0 compiles this library without any error.

The error message looks like a problem on SFINAE. I can try some other expression to dispatch toml::get, but I'm not sure whether it will fix the ICE.
Currently, I don't have any good idea to solve this problem.

[patrikhuber]

Thank you for having a look. Yep, it's gcc 7.3.1 from arch (I'm using Manjaro).
I have a sort-of feeling that this is a problem of arch's gcc build, and hopefully not a regression in upstream gcc 7.3.1. So I would say let's close this for now then.

[patrikhuber]

It definitely wasn't my system at least - a user just reported this on my repo as well: patrikhuber/eos#195

[patrikhuber]

Hi @ToruNiina, hey that's awesome, thank you very much!
Unfortunately the latest Windows Update killed my VMWare Player, so I can't currently test it anymore... sorry about that! I updated the GitHub issue that was opened in my repo, and I'll also test it myself as soon as I can get VMWare Player to work again :-)

[patrikhuber]

I think arch/Manjaro fixed their ICE in their latest update - it seems like with gcc-7.3.1 20180406 even the "old" (before the fix) toml11 version is compiling again.
But anyway I think you were able to simplify lots of things while patching this, so that's great :-)