[UPDATE: Chris Lattner has tweeted his reaction to the BI piece, calling it “fabricated or speculating”.]

The surprise decision of Swift creator and long-time Xcode lead Chris Lattner to leave Apple was in large part driven by his frustration with the culture of secrecy at the company, say developer friends.

Lattner, who was Apple’s head of developer tools and widely respected as the voice of developers within the company, left the company after more than a decade to lead Tesla’s Autopilot software efforts …

Business Insider reports that Lattner had found Apple’s extreme approach to secrecy wearing, especially as his role was to create open-source developer tools, including Swift.

The conflict between Apple’s tight-lipped approach to secrecy and the desire of developers and researchers to be open with their peers outside the company has caused issues before. Academics said back in October that Apple’s ‘off the scale’ approach to secrecy was one of the reasons behind the high-profile problems with Apple Maps, as the company’s researchers were cut off from other work being done in the field.

“He always felt constrained at Apple in terms of what he could discuss publicly — resorting to off-the-record chats, surprise presentations, and the like,” [a friend] told us. “Similarly, I know he was constrained in recruiting and other areas. Eventually I know that can really wear people down.”

Fear of being isolated from the wider scientific community was also said to be hampering Apple’s hiring efforts within the AI field, a claim the company seemingly acknowledged a couple of months later when it announced that it’s AI researchers would, after all, be allowed to publish papers on their work. The first such published paper appeared shortly after the announcement.

BI also pointed to an incident in 2015 when Apple’s entire networking team quit over Apple’s refusal to allow them to participate in an industry-wide network security forum known as the Open Compute Product. The resignations led to Apple changing its mind and joining the OCP.

Keeping even very general roadmaps secret from customers can also cause frustration when trying to plan ahead.

Swift 4 is currently in development under the leadership of Ted Kremenek, with details expected to be announced at next year’s WWDC. Swift 3.1 will be released ahead of this, sometime in Spring.