Testcase requires fuzzing build ac_add_options --enable-fuzzing.

Assertion failure: current->IsDocument() || current->IsShadowRoot(), at src/dom/base/Document.cpp:12276

#0 0x7f5cd9caaef3 in mozilla::dom::GetCorrespondingNodeInDocument(nsINode const*, mozilla::dom::Document&) src/dom/base/Document.cpp:12276:3
#1 0x7f5cd9c5e3ba in CachePrintSelectionRanges src/dom/base/Document.cpp:12357:9
#2 0x7f5cd9c5e3ba in mozilla::dom::Document::CreateStaticClone(nsIDocShell*, nsIContentViewer*, bool*) src/dom/base/Document.cpp:12455:3
#3 0x7f5cd9b5a74e in nsGlobalWindowOuter::Print(nsIPrintSettings*, nsIWebProgressListener*, nsIDocShell*, nsGlobalWindowOuter::IsPreview, nsGlobalWindowOuter::IsForWindowDotPrint, std::function<void (mozilla::dom::PrintPreviewResultInfo const&)>&&, mozilla::ErrorResult&) src/dom/base/nsGlobalWindowOuter.cpp:5388:21
#4 0x7f5cd9b2c78b in nsGlobalWindowInner::PrintPreview(nsIPrintSettings*, nsIWebProgressListener*, nsIDocShell*, mozilla::ErrorResult&) src/dom/base/nsGlobalWindowInner.cpp:3622:3
#5 0x7f5cdaa2651b in mozilla::dom::Window_Binding::printPreview(JSContext*, JS::Handle<JSObject*>, void*, JSJitMethodCallArgs const&) /builds/worker/workspace/obj-build/dom/bindings/WindowBinding.cpp:3208:59
#6 0x7f5cdaf8ce80 in bool mozilla::dom::binding_detail::GenericMethod<mozilla::dom::binding_detail::MaybeCrossOriginObjectThisPolicy, mozilla::dom::binding_detail::ThrowExceptions>(JSContext*, unsigned int, JS::Value*) src/dom/bindings/BindingUtils.cpp:3229:13
#7 0x7f5cddf09f61 in CallJSNative(JSContext*, bool (*)(JSContext*, unsigned int, JS::Value*), js::CallReason, JS::CallArgs const&) src/js/src/vm/Interpreter.cpp:506:13
#8 0x7f5cddf09678 in js::InternalCallOrConstruct(JSContext*, JS::CallArgs const&, js::MaybeConstruct, js::CallReason) src/js/src/vm/Interpreter.cpp:598:12
#9 0x7f5cddf0b243 in InternalCall(JSContext*, js::AnyInvokeArgs const&, js::CallReason) src/js/src/vm/Interpreter.cpp:663:10
#10 0x7f5cddefefe3 in CallFromStack src/js/src/vm/Interpreter.cpp:667:10
#11 0x7f5cddefefe3 in Interpret(JSContext*, js::RunState&) src/js/src/vm/Interpreter.cpp:3336:16
#12 0x7f5cddef6154 in js::RunScript(JSContext*, js::RunState&) src/js/src/vm/Interpreter.cpp:476:13
#13 0x7f5cddf09649 in js::InternalCallOrConstruct(JSContext*, JS::CallArgs const&, js::MaybeConstruct, js::CallReason) src/js/src/vm/Interpreter.cpp:635:13
#14 0x7f5cddf0b243 in InternalCall(JSContext*, js::AnyInvokeArgs const&, js::CallReason) src/js/src/vm/Interpreter.cpp:663:10
#15 0x7f5cddf0b47f in js::Call(JSContext*, JS::Handle<JS::Value>, JS::Handle<JS::Value>, js::AnyInvokeArgs const&, JS::MutableHandle<JS::Value>, js::CallReason) src/js/src/vm/Interpreter.cpp:680:8
#16 0x7f5cde4f579b in JS::Call(JSContext*, JS::Handle<JS::Value>, JS::Handle<JS::Value>, JS::HandleValueArray const&, JS::MutableHandle<JS::Value>) src/js/src/jsapi.cpp:2829:10
#17 0x7f5cda9fe76f in mozilla::dom::IdleRequestCallback::Call(mozilla::dom::BindingCallContext&, JS::Handle<JS::Value>, mozilla::dom::IdleDeadline&, mozilla::ErrorResult&) /builds/worker/workspace/obj-build/dom/bindings/WindowBinding.cpp:868:8
#18 0x7f5cd9ba8bea in mozilla::dom::IdleRequestCallback::Call(mozilla::dom::IdleDeadline&, mozilla::ErrorResult&, char const*, mozilla::dom::CallbackObject::ExceptionHandling, JS::Realm*) /builds/worker/workspace/obj-build/dist/include/mozilla/dom/WindowBinding.h:784:12
#19 0x7f5cd9ca3bb9 in Call /builds/worker/workspace/obj-build/dist/include/mozilla/dom/WindowBinding.h:797:12
#20 0x7f5cd9ca3bb9 in mozilla::dom::IdleRequest::IdleRun(nsPIDOMWindowInner*, double, bool) src/dom/base/IdleRequest.cpp:62:13
#21 0x7f5cd9b1b180 in nsGlobalWindowInner::RunIdleRequest(mozilla::dom::IdleRequest*, double, bool) src/dom/base/nsGlobalWindowInner.cpp:672:12
#22 0x7f5cd9b1a615 in nsGlobalWindowInner::ExecuteIdleRequest(mozilla::TimeStamp) src/dom/base/nsGlobalWindowInner.cpp:700:3
#23 0x7f5cd9b1a444 in IdleRequestExecutor::Run() src/dom/base/nsGlobalWindowInner.cpp:541:13
#24 0x7f5cd807f7ef in mozilla::RunnableTask::Run() src/xpcom/threads/TaskController.cpp:245:16
#25 0x7f5cd807de6a in mozilla::TaskController::DoExecuteNextTaskOnlyMainThreadInternal(mozilla::detail::BaseAutoLock<mozilla::Mutex&> const&) src/xpcom/threads/TaskController.cpp:515:26
#26 0x7f5cd807cfc6 in mozilla::TaskController::ExecuteNextTaskOnlyMainThreadInternal(mozilla::detail::BaseAutoLock<mozilla::Mutex&> const&) src/xpcom/threads/TaskController.cpp:397:15
#27 0x7f5cd807d0c7 in mozilla::TaskController::ProcessPendingMTTask(bool) src/xpcom/threads/TaskController.cpp:171:36
#28 0x7f5cd8082d16 in operator() src/xpcom/threads/TaskController.cpp:85:37
#29 0x7f5cd8082d16 in mozilla::detail::RunnableFunction<mozilla::TaskController::InitializeInternal()::$_3>::Run() /builds/worker/workspace/obj-build/dist/include/nsThreadUtils.h:577:5
#30 0x7f5cd8093f67 in nsThread::ProcessNextEvent(bool, bool*) src/xpcom/threads/nsThread.cpp:1197:14
#31 0x7f5cd8099b0a in NS_ProcessNextEvent(nsIThread*, bool) src/xpcom/threads/nsThreadUtils.cpp:513:10
#32 0x7f5cd8989aa6 in mozilla::ipc::MessagePump::Run(base::MessagePump::Delegate*) src/ipc/glue/MessagePump.cpp:87:21
#33 0x7f5cd88fc233 in MessageLoop::RunInternal() src/ipc/chromium/src/base/message_loop.cc:334:10
#34 0x7f5cd88fc14d in RunHandler src/ipc/chromium/src/base/message_loop.cc:327:3
#35 0x7f5cd88fc14d in MessageLoop::Run() src/ipc/chromium/src/base/message_loop.cc:309:3
#36 0x7f5cdc5d6df8 in nsBaseAppShell::Run() src/widget/nsBaseAppShell.cpp:137:27
#37 0x7f5cdddcfdd3 in XRE_RunAppShell() src/toolkit/xre/nsEmbedFunctions.cpp:913:20
#38 0x7f5cd898a869 in mozilla::ipc::MessagePumpForChildProcess::Run(base::MessagePump::Delegate*) src/ipc/glue/MessagePump.cpp:237:9
#39 0x7f5cd88fc233 in MessageLoop::RunInternal() src/ipc/chromium/src/base/message_loop.cc:334:10
#40 0x7f5cd88fc14d in RunHandler src/ipc/chromium/src/base/message_loop.cc:327:3
#41 0x7f5cd88fc14d in MessageLoop::Run() src/ipc/chromium/src/base/message_loop.cc:309:3
#42 0x7f5cdddcf9b8 in XRE_InitChildProcess(int, char**, XREChildData const*) src/toolkit/xre/nsEmbedFunctions.cpp:744:34
#43 0x55acad533657 in content_process_main src/browser/app/../../ipc/contentproc/plugin-container.cpp:56:28
#44 0x55acad533657 in main src/browser/app/nsBrowserApp.cpp:304:18

A Pernosco session is available here: https://pernos.co/debug/cIMO95Nu2x_StXErtOvZwA/index.html

Bugmon Analysis:
Verified bug as reproducible on mozilla-central 20201020145547-5b5ffbe4add9.
The bug appears to have been introduced in the following build range:

Start: a25601920fab8afe0b399e3750c53cf411e3c8ec (20200827201039)
End: ae59b435ba7e86aca38535e07e7b12609bb9a9b1 (20200827225009)
Pushlog: https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=a25601920fab8afe0b399e3750c53cf411e3c8ec&tochange=ae59b435ba7e86aca38535e07e7b12609bb9a9b1