We're using different senses of "drop in", it's a bit of a vague term. Rust is interoperable with C (it can do C FFI) but it is not compatible with C (C code is

We're using different senses of "drop in", it's a bit of a vague term. Rust is interoperable with C (it can do C FFI) but it is not compatible with C (C code is not Rust code and Rust code is not C code). Compare this to a language like Carbon or C++; that is what I'd call a "drop in replacement", because they are compatible, using the definitions I've provided. If FFI were sufficient, Python would be a "C replacement." It's true that there is a path to integrating Rust into C projects and potentially replacing C in that project, I just see lots of threads on HN derailed by the statement "Rust is a C replacement", and I think using more nuanced language would help.