RFC 256, 2014-09. https://rust-lang.github.io/rfcs/0256-remove-refcounting-gc-...
Includes « I (and I think the majority of the Rust core team) still believe that there are use cases that would be well handled by a proper tracing garbage collector. »
https://news.ycombinator.com/item?id=8312327 A core developer says
« I wouldn't be so quick to give up on GC support yet! "We have a plan!" But I don't think we'll have it in for Rust 1.0. And it's true that, even if we never do get it to work in a satisfactory way, the language works just fine without it. »
By 2015-04 ("Fearless Concurrency"), "Memory safety without garbage collection." is a "key value proposition" (this isn't quite the same as saying "we never want Garbage Collection", of course).
2016-08 https://manishearth.github.io/blog/2016/08/18/gc-support-in-... « Recently we (Felix, Niko, and I) have been working on getting compiler-level GC support for Rust. »
2018-10 withoutboats has a research garbage collector as a library: https://boats.gitlab.io/blog/post/shifgrethor-i/ The intro post includes « I do not expect we will ever “add GC to Rust” ».
2021 summary of options: https://manishearth.github.io/blog/2021/04/05/a-tour-of-safe...