Matz, the inventor of Ruby, is using Claude Code to build an ahead-of-time compiler for his own language. Spinel performs whole-program type inference, generates C, and produces standalone native executables. This is much more interesting than a generic claim that AI can code: a person with an extremely precise model of the problem is using a machine to pursue a compiler that would otherwise require too much implementation work.
The division of labor matters. Claude did not invent Ruby or decide which kinds of dynamism to sacrifice. It made the language designer’s backlog cheaper.