Silence unreachable code warnings in MSVC when FMT_USE_EXCEPTIONS are…

[mattiasljungstrom]

Removes warnings about unreachable code in VS 2022, 17.14.12 when exceptions are disabled.

[vitaut]

Please post the full warning.

[vitaut]

I wonder if this can be

if (const_check(true)) {

[mattiasljungstrom]

Tried this version and it unfortunately doesn't stop the warnings:

FMT_FUNC void report_error(const char* message) {
#if FMT_USE_EXCEPTIONS
  // Use FMT_THROW instead of throw to avoid bogus unreachable code warnings
  // from MSVC.
  FMT_THROW(format_error(message));
#else
  if (detail::const_check(true)) {
    fputs(message, stderr);
    abort();
  }
#endif
}

[mattiasljungstrom]

Please post the full warning.

Basically every return that happens after the call to report_error():

fmt\include\fmt\format.h(3522): warning C4702: unreachable code
fmt\include\fmt\format.h(2192): warning C4702: unreachable code
fmt\include\fmt\base.h(901): warning C4702: unreachable code
fmt\include\fmt\base.h(901): warning C4702: unreachable code
fmt\include\fmt\format.h(3439): warning C4702: unreachable code
fmt\include\fmt\base.h(1433): warning C4702: unreachable code
fmt\include\fmt\base.h(1563): warning C4702: unreachable code
fmt\include\fmt\base.h(1567): warning C4702: unreachable code
fmt\include\fmt\base.h(1349): warning C4702: unreachable code
fmt\include\fmt\base.h(1590): warning C4702: unreachable code
fmt\include\fmt\base.h(1618): warning C4702: unreachable code
fmt\include\fmt\base.h(1625): warning C4702: unreachable code

[vitaut]

Could you provide a gobolt repro? I tried to repro in https://www.godbolt.org/z/Mjb6xY4vT but to no avail.

[mattiasljungstrom]

Could you provide a gobolt repro? I tried to repro in https://www.godbolt.org/z/Mjb6xY4vT but to no avail.

It seems to only trigger in release mode, and with /W4 /O2

https://www.godbolt.org/z/YfPYK6334

[vitaut]

In general we only care about /W3 but I guess this one is trivial to fix so let's merge.

[vitaut]

Merged, thanks.