How to do properly TemplateArgument and TemplateParameter matching?

[harsszegi]

Hi,

I can't get my head around the following issue. Assume I have something like this:

"
#include

void function1(std::variant<char, int, double, long> input);
"

when I parse it, I have obviously different amount of TemplateParameters and TemplateArguments, like
an std::variant contains 2 parameters (_Void and _Types) and they should be resolved to 4 arguments (char, int, double, long).

I have absolutely no idea how can I figure out which set of arguments are resolving which template parameter?
Is there any documentation on it? Or how shall it be done?
Thanks,