insert else branch to avoid unreachable code warning

[torsten48]

at least MSC caused warning C4702: unreachable code

[sunmy2019]

lgtm

[vitaut]

Thanks for the PR but could you provide a godbolt repro demonstrating the issue?

[torsten48]

Godbolt seems to currently have a problem using MSC and fmt:
https://godbolt.org/z/x638qzfc9

but here is my max reduced example:

test.cpp
`#pragma warning(3:4702)

#define FMT_HEADER_ONLY
#define FMT_UNICODE 0

#include "fmt/format.h"
#include "fmt/compile.h"

int main()
{
fmt::print(FMT_COMPILE("The answer is {}."), "42");
return 0;
}`

MSC (VS 17.11.1)
`C:\build\tt>cl /W3 /std:c++20 /EHsc test.cpp
Microsoft (R) C/C++ Optimizing Compiler Version 19.41.34120 for x64
Copyright (C) Microsoft Corporation. All rights reserved.

test.cpp
C:\build\tt\fmt\base.h(2162): warning C4267: '=': conversion from 'size_t' to 'unsigned long', possible loss of data
C:\build\tt\fmt\compile.h(147) : warning C4702: unreachable code
Microsoft (R) Incremental Linker Version 14.41.34120.0
Copyright (C) Microsoft Corporation. All rights reserved.

/out:test.exe
test.obj`

Notice the string "42"!

[vitaut]

thanks