C:\Dev>type repro.cpp

C:\Dev>cl /std:c++latest repro.cpp
Microsoft (R) C/C++ Optimizing Compiler Version 19.43.34808 for x64
Copyright (C) Microsoft Corporation.  All rights reserved.

/std:c++latest is provided as a preview of language features from the latest C++
working draft, and we're eager to hear about bugs and suggestions for improvements.
However, note that these features are provided as-is without support, and subject
to changes or removal as the working draft evolves. See
https://go.microsoft.com/fwlink/?linkid=2045807 for details.

repro.cpp
repro.cpp(7): error C2440: '<function-style-cast>': cannot convert from 'initializer list' to 'std::ispanstream'
repro.cpp(7): note: 'std::basic_ispanstream<char,std::char_traits<char>>::basic_ispanstream': ambiguous call to overloaded function
C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.43.34808\include\spanstream(210): note: could be 'std::basic_ispanstream<char,std::char_traits<char>>::basic_ispanstream(std::span<const _Elem,18446744073709551615>)'
        with
        [
            _Elem=char
        ]
C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.43.34808\include\spanstream(207): note: or       'std::basic_ispanstream<char,std::char_traits<char>>::basic_ispanstream(std::span<_Elem,18446744073709551615>,std::ios_base::openmode)'
        with
        [
            _Elem=char
        ]
repro.cpp(7): note: while trying to match the argument list '(std::string)'