JS ERROR: TypeError: malformed UTF-8 character sequence at offset 0 and segfault

I was trying to focus my Firefox window by pressing Super+2 when gnome-shell crashed.

journalctl shows

lapkr. 06 16:38:58 blynas gnome-shell[3417]: JS ERROR: TypeError: malformed UTF-8 character sequence at offset 0
                                             _filterKeybinding@resource:///org/gnome/shell/ui/windowManager.js:1825:43
lapkr. 06 16:38:58 blynas gnome-shell[3417]: GNOME Shell crashed with signal 11
lapkr. 06 16:38:58 blynas gnome-shell[3417]: == Stack trace for context 0x56068fb2e3e0 ==

stack trace with debug symbols (produced by apport-retrace --gdb --sandbox system --cache ~/.cache/apport-retrace /var/crash/_usr_bin_gnome-shell.1000.crash):

Program terminated with signal SIGSEGV, Segmentation fault.
#0 __GI_raise (sig=<optimized out>) at ../sysdeps/unix/sysv/linux/raise.c:50
50 ../sysdeps/unix/sysv/linux/raise.c: Toks failas ar aplankas neegzistuoja.
[Current thread is 1 (Thread 0x7f5c91796cc0 (LWP 3417))]
(gdb) bt
#0 __GI_raise (sig=<optimized out>) at ../sysdeps/unix/sysv/linux/raise.c:50
#1 0x000056068ef0852a in dump_gjs_stack_on_signal_handler ()
#2 <signal handler called>
#3 0x00005606b18aca40 in ?? ()
#4 0x00007f5c971a9f11 in invoke_handler (binding=0x56069dc351c0, event=0x5606b4c878c0, window=0x56069dc351c0, handler=<optimized out>,
    display=0x5606900e0020) at ../src/core/keybindings.c:1921
#5 process_event (display=display@entry=0x5606900e0020, window=window@entry=0x56069e5ad220, event=event@entry=0x5606b4c878c0)
    at ../src/core/keybindings.c:2005
#6 0x00007f5c971ab83e in process_special_modifier_key (display=display@entry=0x5606900e0020, event=event@entry=0x5606b4c878c0,
    window=window@entry=0x56069e5ad220, modifier_press_only=modifier_press_only@entry=0x5606900e01a8,
    resolved_key_combo=resolved_key_combo@entry=0x5606900e0198, trigger_callback=0x7f5c971a5100 <meta_display_overlay_key_activate>)
    at ../src/core/keybindings.c:2051
#7 0x00007f5c971ac976 in process_overlay_key (window=0x56069e5ad220, event=0x5606b4c878c0, display=0x5606900e0020)
    at ../src/core/keybindings.c:2151
#8 process_key_event (event=0x5606b4c878c0, window=0x56069e5ad220, display=0x5606900e0020) at ../src/core/keybindings.c:2228
#9 meta_keybindings_process_event (display=display@entry=0x5606900e0020, window=window@entry=0x56069e5ad220,
    event=event@entry=0x5606b4c878c0) at ../src/core/keybindings.c:2326
#10 0x00007f5c971a801c in meta_display_handle_event (event=0x5606b4c878c0, display=0x5606900e0020) at ../src/core/events.c:358
#11 event_callback (event=0x5606b4c878c0, data=0x5606900e0020) at ../src/core/events.c:479
#12 0x00007f5c97368235 in _clutter_event_process_filters ()
   from /tmp/apport_sandbox_6sb0y3pp/usr/lib/x86_64-linux-gnu/mutter-5/libmutter-clutter-5.so.0
#13 0x00007f5c9737e585 in emit_keyboard_event ()
   from /tmp/apport_sandbox_6sb0y3pp/usr/lib/x86_64-linux-gnu/mutter-5/libmutter-clutter-5.so.0
#14 0x00007f5c9721c0e0 in meta_input_device_native_process_kbd_a11y_event (event=0x5606b4c878c0, device=0x56068fd782b0,
    emit_event_func=0x7f5c9737e570 <emit_keyboard_event>) at ../src/backends/native/meta-input-device-native.c:1195
#15 0x00007f5c9737fa36 in _clutter_process_event ()
   from /tmp/apport_sandbox_6sb0y3pp/usr/lib/x86_64-linux-gnu/mutter-5/libmutter-clutter-5.so.0
#16 0x00007f5c97399d08 in _clutter_stage_queue_event ()
   from /tmp/apport_sandbox_6sb0y3pp/usr/lib/x86_64-linux-gnu/mutter-5/libmutter-clutter-5.so.0
#17 0x00007f5c9721901c in meta_event_dispatch (g_source=<optimized out>, callback=<optimized out>, user_data=<optimized out>)
    at ../src/backends/native/meta-device-manager-native.c:686
#18 0x00007f5c97cf984d in g_main_context_dispatch () from /tmp/apport_sandbox_6sb0y3pp/usr/lib/x86_64-linux-gnu/libglib-2.0.so.0.6200.1
#19 0x00007f5c97cf9ad0 in g_main_context_iterate.isra () from /tmp/apport_sandbox_6sb0y3pp/usr/lib/x86_64-linux-gnu/libglib-2.0.so.0.6200.1
#20 0x00007f5c97cf9dc3 in g_main_loop_run () from /tmp/apport_sandbox_6sb0y3pp/usr/lib/x86_64-linux-gnu/libglib-2.0.so.0.6200.1
#21 0x00007f5c971aefe0 in meta_run () at ../src/core/main.c:676
#22 0x000056068ef07d85 in main ()

jadahl on IRC asked me to look at a couple of locals in invoke_handler:

(gdb) frame 4
#4 0x00007f5c971a9f11 in invoke_handler (binding=0x56069dc351c0, event=0x5606b4c878c0, window=0x56069dc351c0, handler=<optimized out>,
    display=0x5606900e0020) at ../src/core/keybindings.c:1921
1921 ../src/core/keybindings.c: Toks failas ar aplankas neegzistuoja.
(gdb) print *binding->handler
$1 = {name = 0x5606b49e5e80 "", func = 0x5606b18aca40, default_func = 0x7f5c5b333f10, data = 0, flags = 0, user_data = 0x5606b10c4e30,
  user_data_free_func = 0x7f5c97487c60}
(gdb) print *binding
$2 = {name = 0x5606b49d15d0 "\220T\241\234\006V", combo = {keysym = 50, keycode = 0, modifiers = META_VIRTUAL_SUPER_MASK},
  resolved_combo = {keycodes = 0x5606a0c44d70, len = 1, mask = 64}, flags = 0, handler = 0x5606b37830b0}

I'm on Ubuntu 19.10 with gnome-shell 3.34.1.

Downstream bug report: https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1851528