Chris Lattner, the mind behind compiler infrastructure project LLVM and Apple’s Swift language, has left the Swift core team and the Swift Evolution community – a group dedicated to taking community voices into account when improving the programming language.

Apparently, Lattner hasn’t been part of the core team since autumn 2021, when he tried discussing what he perceived as a toxic meeting environment with project leadership after an especially noteworthy call made him take a break in summer. “[…] after avoiding dealing with it, they made excuses, and made it clear they weren’t planning to do anything about it. As such, I decided not to return” Lattner wrote in his explanation post.

Back then, he planned to keep participating via the Swift Evolution community “but after several discussions generating more heat than light, when my formal proposal review comments and concerns were ignored by the unilateral accepts, and the general challenges with transparency working with core team, I decided that my effort was triggering the same friction with the same people, and thus I was just wasting my time.”

Lattner had been the steering force behind Swift since the language’s inception in 2010. However, after leaving Apple in 2017 and handing over his project lead role, design premises like “single things that compose” seem to have fallen by the wayside, making the decision to move on completely easier for language-creator Lattner.

“Swift has a ton of well meaning and super talented people involved in and driving it. They are trying to be doing the best they can with a complicated situation and many pressures (including lofty goals, fixed schedules, deep bug queues to clear, internal folks that want to review/design things before the public has access to them, and pressures outside their team) that induce odd interactions with the community. By the time things get out to us, the plans are already very far along and sometimes the individuals are attached to the designs they’ve put a lot of energy into. This leads to a challenging dynamic for everyone involved.”

Probably as a consequence of the move, the Swift core team is currently looking to restructure project leadership. According to Swift project lead Ted Kremenek, the coming weeks will see the introduction of a new language workgroup, which is going to focus on the evolution of the Swift language. “The intent is to free the core team to invest more in overall project stewardship and create a larger language workgroup that can incorporate more community members in language decisions.”

Kremenek also used the announcement to thank Lattner for his leadership throughout the formative years of the project, writing “it has been one of the greatest privileges of my life to work with Chris on Swift.”

While appreciative of the plans – after all Lattner knows about the problems of keeping processes transparent from LLVM – they don’t seem to have helped convince the LLVM creator to rethink his decision. He probably wouldn’t have lots of free time anyways, as Lattner is known to always be “very busy”. His latest endeavour is AI infrastructure company Modular.AI.

Chris Lattner isn’t new to the field of machine learning, as he helped bring Google’s Cloud TPUs to market and worked as a senior director and distinguished engineer for the company’s TensorFlow Infrastructure and Technologies division from 2017 to 2020. Before that, he had a brief stint at Tesla, helping out with its autopilot software.