Replace use of newer C++ library feature with older equivalent #3638
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When compiling something like the following bit of code:
on an environment that uses the older C++11 standard library with C++17 language features enabled, you get this error (significantly shortened):
The error comes from the usage of
std::is_default_constructible_v
, a template that was not added until C++17. This usage is gated by a check for__cpp_if_constexpr
, another C++17 feature, but the compiler I am using does have support forif constexpr
and defines the macro.Unfortunately, having modern C++ features like
if constexpr
does not imply that a modern C++ standard library is available.This replacement fixes the error for me and has equivalent behavior to the previous code. Judging by the surrounding bits of code, a standard library version of at least C++11 was already assumed so this is hopefully all good.