The project cannot be built in non-release mode with >=C++20 and GCC

[Tomaqa]

In your project, you use deprecated template-ids within constructors:

.../_deps/marabou-src/src/common/Vector.h:36:14:
warning: template-id not allowed for constructor in C++20 [-Wtemplate-id-cdtor]
   36 |     Vector<T>()

Also, your CMakeLists.txt defines for non-Clang non-release mode the following:

set(COMPILE_FLAGS  -Wall -Wextra -Werror -MMD ) #-Wno-deprecated

This causes the warnings to turn into errors.

Since I used your project as a submodule, I have not figured out how to force a different C++ standard just for your project.
What worked out for me was manually modifying the CMakeLists.txt.

I do not know what is the situation with Clang.

I would suggest either fixing these constructors, using -Wno-template-id-cdtor for GCC (which may not fix it for other compilers), or simply dropping -Werror.

[Tomaqa]

With GCC13 I experienced that such constructors are not even considered as warnings but directly as errors, so removing -Werror does not resolve the issue there.

[MatthewDaggitt]

Link to change in standard: http://eel.is/c++draft/diff.cpp17.class#2