>For example, Go uses a non-copying GC because Google wanted it to work with their existing C++ code more easily. Copying GCs are hard to get 100% correct when you're dealing with an outside runtime that doesn't expect things to be moved around in memory.

Do you have a source for this?

C# has a copying GC, and easy interop with C has always been one of its strengths. From the perspective of the user, all you need to do is to "pin" a pointer to a GC-allocated object before you access it from C so that the collector avoids moving it.

I always thought it had more to do with making the implementation simpler during the early stages of development, with the possibility of making it a copying GC some time in the feature (mentioned somewhere in stdlib's sources I think) but it never came to fruition because Go's non-copying GC was fast enough and a lot of code has since been written with the assumption that memory never moves. Adding a copying GC today would probaby break a lot of existing code.