VS2017 won't compile without Conformance Mode

[simonask]

VS2017 won't compile without Conformance Mode

[Trass3r]

You mean /permissive-?

[tkozybski]

Yes

[simonask]

I'm confused: Does it work with or without /permissive-? We build the tests and benchmarks with /permissive-, and I would be rather surprised to see something compile in non-permissive mode that does compile in permissive mode. Still, would not be the first time MSVC surprised me...

@tkozybski Can you check if this is still a problem in the version 2.0 branch (#10)?

[tkozybski]

I'm confused: Does it work with or without /permissive-? We build the tests and benchmarks with /permissive-, and I would be rather surprised to see something compile in non-permissive mode that does compile in permissive mode. Still, would not be the first time MSVC surprised me...

@tkozybski Can you check if this is still a problem in the version 2.0 branch (#10)?

@simonask IIt doesn't compile if Conformance Mode is set to "No", with 2.0 as well. It does compile with VS2019 though (platform toolset v142, doesn't work on v141).

[simonask]

Ah, now I see. I'll take a look at it. :-)

[simonask]

Ok, the issue seems to be that VS2017 does not parse C++17 fold expressions correctly. Microsoft claims that the latest versions of VS2017 had a number of bugs fixed related to fold expressions, but apparently not enough, which is unfortunate.

@tkozybski Is using VS2019 not an option for you?

I am closing this for now, since supporting buggy compilers is not a goal.

[Trass3r]

It fails without that mode too: https://godbolt.org/z/N8T5n5

@tkozybski Is using VS2019 not an option for you?

Yep, since they are binary compatible there's no good reason not to.

[Kijewski]

Version 2.0 works in MSVC 19.20 and higher: https://godbolt.org/z/ryyBvJ