Even then, you still need ABI consistency between compilers if you want to link together codebases written in different languages (e.g. C and Rust).

In practice this almost always 'just works' because most cross-language calls simply don't use the kinds of complicated types discussed in the blog post. They tend to stick to simple integer and pointer types, where ABI consistency is usually a given.

Though you can still get into trouble when passing function pointers, especially when combined with some modern control-flow integrity systems.