Rust 1.36.0 pre-release testing

The 1.36.0 pre-release is ready for testing. Rust 1.36.0 is scheduled to be released on Thursday July 4th. Release notes can be found here:

You can try it out locally with:

RUSTUP_DIST_SERVER= rustup update stable

The index is


I have a problem while building firefox-60.7.2esr with rustc-1.36.0, whereas it build fine with rustc-1.35.0.

A bug report has been opened on firefox side: but it has been classified as WONTFIX as it seems it is required to downstream to use rustc-1.24.0 to build it.

But I wonder if the problem (regression from stable to stable) is expected, and where is the origin (change in libstd ? in compiler ? somewhere else ?).

Any hint to help building firefox-esr with up-to-date compiler would be also appreciate.


On FreeBSD we patch firefox-esr and thunderbird like this at the moment:

Here’s the regression on the playground:

Compiles on stable, fails on beta.

It seems that the inferred UnwindSafe conditions of HashMap changed with the use of hashbrown~~, but I failed to reduce this to just using a simple local !UnwindSafe type, so it may also be related to the RegexSet~~.

EDIT: minimized

I opened an issue here:


HashMap missing the UnwindSafe impl issue should be fixed, and new artifacts have been published; I’ve also updated the link in the original post. Thanks for checking the artifacts!