The session that they did together with AdaCore presenting which languages they went through and why they picked Ada in the end.
Rust syntax was one of the factors that played against it.
"Securing the Future of Safety and Security of Embedded Software"
https://www.adacore.com/webinars/securing-future-of-embedded...
Page 35,
https://www.slideshare.net/AdaCore/securing-the-future-of-sa...