This bug is for crash report bp-4a1fc711-bc3f-4eaf-9018-6711a0200327.

Top 10 frames of crashing thread:

0 libxul.so RustMozCrash mozglue/static/rust/wrappers.cpp:17
1 libxul.so mozglue_static::panic_hook mozglue/static/rust/lib.rs:89
2 libxul.so core::ops::function::Fn::call src/libcore/ops/function.rs:72
3 libxul.so std::panicking::rust_panic_with_hook src/libstd/panicking.rs:475
4 libxul.so rust_begin_unwind src/libstd/panicking.rs:375
5 libxul.so std::panicking::begin_panic_fmt src/libstd/panicking.rs:326
6 libxul.so webrender::scene_building::SceneBuilder::build_item gfx/wr/webrender/src/scene_building.rs:1515
7 libxul.so webrender::scene_building::SceneBuilder::build_items gfx/wr/webrender/src/scene_building.rs:756
8 libxul.so webrender::scene_building::SceneBuilder::build_items gfx/wr/webrender/src/scene_building.rs:932
9 libxul.so webrender::scene_building::SceneBuilder::build_item gfx/wr/webrender/src/scene_building.rs:1005

This is happening on beta across all platforms. The raw crash reason is:

internal error: entered unreachable code: Iterator logic error

I think the patch for bug 1624125 might fix this.

Because this bug's Severity has not been changed from the default since it was filed, and it's Priority is P3 (Backlog,) indicating it has been triaged, the bug's Severity is being updated to S3 (normal.)

The last crash was almost three weeks ago. I believe the remaining issues were fixed in bug 1633453.