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https://issues.apache.org/jira/browse/MINIFICPP-2254?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Marton Szasz resolved MINIFICPP-2254.
-------------------------------------
Resolution: Fixed
> Simplify template used by log_format_string to make VS2022 understand it
> ------------------------------------------------------------------------
>
> Key: MINIFICPP-2254
> URL: https://issues.apache.org/jira/browse/MINIFICPP-2254
> Project: Apache NiFi MiNiFi C++
> Issue Type: Bug
> Reporter: Ferenc Gerlits
> Assignee: Ferenc Gerlits
> Priority: Minor
> Time Spent: 20m
> Remaining Estimate: 0h
>
> The {{map_args}} class template used by the {{log_format_string}} class
> template in Logger.h uses some tricky template magic so that we can call the
> logger both with invocable objects and plain value objects.
> This template magic compiled fine in VS2019, as well as VS2022 up to version
> 19.35. However, since version 19.36, it no longer compiles.
> {code:java}
> #include <concepts>
> #include <type_traits>
> template<typename... Funcs>
> struct overloaded : Funcs... {
> using Funcs::operator()...;
> };
> // deduction guide. doesn't hurt, but doesn't help either
> //template<typename... Funcs>
> //overloaded(Funcs...) -> overloaded<Funcs...>;
> const auto inline map_args = overloaded {
> [](std::invocable<> auto&& f) { return
> std::invoke(std::forward<decltype(f)>(f)); }, // works in 19.35, fails in
> 19.36
> // [](auto&& f) requires(std::is_invocable_v<decltype(f)>) { return
> std::invoke(std::forward<decltype(f)>(f)); }, // this works in both
> [](auto&& value) { return std::forward<decltype(value)>(value); }
> };
> int main() {
> return map_args(int());
> }
> {code}
> error message in 19.36 (and 19.37):
> {code:java}
> <source>(20): error C2668: '<lambda1>@map_args::operator ()': ambiguous call
> to overloaded function
> <source>(14): note: could be 'auto <lambda1>@map_args::operator ()<int>(_T3
> &&) const'
> with
> [
> _T3=int
> ]
> <source>(16): note: or 'auto <lambda2>@map_args::operator ()<int>(_T4
> &&) const'
> with
> [
> _T4=int
> ]
> <source>(20): note: while trying to match the argument list '(int)'
> Compiler returned: 2 {code}
>
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