I'd take a language that have built in support for tagged union over having to import a module and rely on templates

I know of sumtype, and i think it is a mistake for D to rely on this for such important language feature

I'm not a language dev, so i can't do much to help, using switch/union/enum is more natural, is cleaner, and is easier to add support for IDEs, everyone on the same page

That's in areas like this where the language falls short, and i can see people instead choosing alternatives

https://github.com/dlang/phobos/blob/master/std/sumtype.d

a mess of templates and imports to std.traits

using this will make your compile speed tank.. another reason to avoid

it's very sad that people recommend this instead of asking for built-in version, makes me sometimes reconsider my choice to use the language

if they expect language improvements to be templates, what atrocity will be added next?

this is on the same level as std::bool from C++