Don't turn your brain off

Summary

Chris Lattner created some of the most influential programming languages and compiled technologies of the past 20 years. He is the creator of LLVM, used by languages like Swift, Rust, and C++, created the Swift programming language, worked on TensorFlow, and now works on the Mojo programming language. In this conversation, they cover the origin story of LLVM and how Chris managed to convince Apple to move all major Apple dev tools over to support this new technology, how Chris created Swift at Apple, including how they worked on this new language in secrecy for a year and a half, and why Mojo is a language Chris expects to help build efficient AI programs easier and faster, how Chris uses AI tools, and what productivity improvements he sees as a very experienced programmer, and many more. If you’d like to understand how a truly standout software engineer like Chris thinks and gets things done, and how he’s designing a language that could be a very important part of AI engineering, then this episode is for you. Chris Lattner encourages his team to use AI coding tools like Claude Code and Cursor. For experienced programmers like himself, these tools provide about 10% productivity gains, mainly by handling mechanical rewrites and reducing tedious work, which increases both productivity and coding enjoyment.However, the impact varies significantly by use case. For PMs and prototypers building wireframes, AI tools are transformative—enabling 10x productivity improvements on tasks that might not otherwise get done. But for production coding, results are mixed. Sometimes AI agents spend excessive time and tokens on problems a human could solve faster directly.His key concern: programmers must keep their brains engaged. AI should be a “human assist, not a human replacement.” For production applications, developers need to review code, understand architecture, and maintain deep system knowledge. What he cares about most is keeping production architecture clean and well-curat...