This bug was filed from the Socorro interface and is report bp-7a12db29-38d3-4985-b93e-fab940181114. ============================================================= Top 10 frames of crashing thread: 0 @0x10280 1 xul.dll bool std::_Func_impl_no_alloc<`lambda at z:/build/build/src/layout/base/RestyleManager.cpp:1802:31', bool, const mozilla::Maybe<unsigned long long>&, DisplayItemType>::_Do_call 2 xul.dll mozilla::FrameLayerBuilder::EnumerateGenerationForDedicatedLayers layout/painting/FrameLayerBuilder.cpp:6961 3 xul.dll mozilla::layers::AnimationInfo::EnumerateGenerationOnFrame gfx/layers/AnimationInfo.cpp:248 4 xul.dll bool mozilla::RestyleManager::ProcessPostTraversal layout/base/RestyleManager.cpp:2833 5 xul.dll bool mozilla::RestyleManager::ProcessPostTraversal layout/base/RestyleManager.cpp:2856 6 xul.dll bool mozilla::RestyleManager::ProcessPostTraversal layout/base/RestyleManager.cpp:2856 7 xul.dll bool mozilla::RestyleManager::ProcessPostTraversal layout/base/RestyleManager.cpp:2856 8 xul.dll bool mozilla::RestyleManager::ProcessPostTraversal layout/base/RestyleManager.cpp:2856 9 xul.dll bool mozilla::RestyleManager::ProcessPostTraversal layout/base/RestyleManager.cpp:2856 ============================================================= There is 1 crash in nightly 65 with buildid 20181114100226. In analyzing the backtrace, the regression may have been introduced by patch [1] to fix bug 1504929. [1] https://hg.mozilla.org/mozilla-central/rev?node=f82c7330018b

To be honest, I don't quite understand what happened there. Maybe a compiler (MSVC?) bug?

Low volume crash, has a priority set. Marking fix-optional to remove this from regression triage. Happy to still take a patch in nightly.