Continuing this saga...

1. Crash HackStudio (for example, by right-click-deleting a file in the directoryview)
2. Wait for CrashReporter to load
3. Click "Debug in Hack Studio"
4. HackStudio slowly attempts to load
5. It crashes, and we get this in the logs:

67.659 [#0 HackStudio(57:57)]: Unable to allocate 131080, expanding kmalloc heap
67.659 [#0 HackStudio(57:57)]: Adding kmalloc subheap @ 0xc3700000 with size 1048576
67.710 HackStudio(57:57): ASSERTION FAILED: rc == 0
../../Userland/Libraries/LibCore/Stream.cpp:393
67.710 [#0 HackStudio(57:57)]: Terminating HackStudio(57) due to signal 6
67.714 [#0 FinalizerTask(4:4)]: Backtrace:
0xdeadc0de  Kernel::Processor::switch_context(Kernel::Thread*&, Kernel::Thread*&) + 0x31e
0xdeadc0de  Kernel::Scheduler::context_switch(Kernel::Thread*) [clone .localalias] + 0x222
0xdeadc0de  Kernel::Scheduler::pick_next() [clone .localalias] + 0x1df
0xdeadc0de  Kernel::Processor::check_invoke_scheduler() [clone .localalias] + 0x175
0xdeadc0de  Kernel::Thread::die_if_needed() [clone .localalias] + 0x40d
0xdeadc0de  syscall_handler + 0x1d42
0xdeadc0de  syscall_asm_entry + 0x31
0x0f0d2905  libc.so: .text + 0x16905
0x0f0bda6a  libc.so: .text + 0x1a6a
0x0f0be4fd  libc.so: .text + 0x24fd
0xaa5f220f  libcore.so.serenity: .text + 0x3d20f
0xaa5f3534  libcore.so.serenity: .text + 0x3e534
0xb0c9da14  /bin/HackStudio: .text + 0x31a14
0xb0c9dcc4  /bin/HackStudio: .text + 0x31cc4
0xb0cc9d44  /bin/HackStudio: .text + 0x5dd44
0xb0c9e9d4  /bin/HackStudio: .text + 0x329d4
0xb0c92350  /bin/HackStudio: .text + 0x26350
0xb0c941f1  /bin/HackStudio: .text + 0x281f1
0xb0cc0b00  /bin/HackStudio: .text + 0x54b00
0xb0cc1444  /bin/HackStudio: .text + 0x55444
0xb0c72125  /bin/HackStudio: .text + 0x6125
0x0e860e16  libgui.so.serenity: .text + 0x16e16
0x0e86127f  libgui.so.serenity: .text + 0x1727f
0x0e9048a1  libgui.so.serenity: .text + 0xba8a1
0xb0c7340f  /bin/HackStudio: .text + 0x740f
0xb0cbeff3  /bin/HackStudio: .text + 0x52ff3
0xb0cde009  /bin/HackStudio: .text + 0x72009
0x7f32c1d3  libmain.so.serenity: .text + 0x1d3
0xb0c6e31d  /bin/HackStudio: .text + 0x231d
67.723 [#0 FinalizerTask(4:4)]: Generating coredump for pid: 57
67.723 [FinalizerTask(4:4)]: VirtualRangeAllocator: Failed to allocate anywhere: size=268431360, alignment=4096
68.016 CrashDaemon(9:9): New coredump file: /tmp/coredump/HackStudio_57_1642513291
[FinalizerTask(4:4)]: Failed to write coredump: Error(errno=12)

So, for some reason it's failing to allocate 268 MB of memory. This doesn't happen when using "Debug in Hack Studio" for other application crashes, only HackStudio ones.