Freeciv

The patch I've recently published on Bug #885482 seems to belong more here then there. It helps.

Which branch is that backtrace from? Line numbers seem to match with none.

It's a modified branch but I can reproduce it on a standard client. Probably there is a related problem in specifying worker tasks, especially in Qt where there is seemingly no way to cancel a task and scrolling with RMB that is the main way to navigate the main map produces menus on city maps. Currently, I have one or two cities in LT54 that can't be opened in any standard clients after some misclicks in Qt.'
This is listing from LT54 current S2_6 branch.

Thread 1 "freeciv-gtk3" received signal SIGSEGV, Segmentation fault.
0x000055555560d624 in fill_sprite_array (t=<optimized out>, 
    sprs=sprs@entry=0x7fffffffce40, layer=layer@entry=LAYER_WORKERTASK, 
    ptile=<optimized out>, ptile@entry=0x55555d01b658, pedge=0x0, pcorner=0x0, 
    punit=0x0, pcity=0x0, citymode=0x55555d7b4d40, putype=0x0)
    at tilespec.c:5888
warning: Source file is more recent than executable.
5888                ADD_SPRITE(t->sprites.extras[extra_index(ptask->tgt)].rmact,
(gdb) backtrace
#0  0x000055555560d624 in fill_sprite_array
    (t=<optimized out>, sprs=sprs@entry=0x7fffffffce40, layer=layer@entry=LAYER_WORKERTASK, ptile=<optimized out>, 
    ptile@entry=0x55555d01b658, pedge=0x0, pcorner=0x0, punit=0x0, pcity=0x0, citymode=0x55555d7b4d40, putype=0x0) at tilespec.c:5888
#1  0x00005555555dbf04 in put_one_element
    (pcanvas=pcanvas@entry=0x7fffffffd730, zoom=zoom@entry=1, layer=layer@entry=LAYER_WORKERTASK, ptile=ptile@entry=0x55555d01b658, pedge=<optimized out>, pcorner=<optimized out>, punit=<optimized out>, pcity=0x0, canvas_x=192, canvas_y=0, citymode=0x55555d7b4d40, putype=0x0) at mapview_common.c:1325
#2  0x00005555555acff4 in city_dialog_redraw_map
    (pcity=0x55555d7b4d40, pcanvas=pcanvas@entry=0x7fffffffd730)
    at citydlg_common.c:210
#3  0x00005555556210dc in city_dialog_update_map (pdialog=0x55555b0101c0)
    at citydlg.c:1872
#4  0x0000555555623a7e in real_city_dialog_refresh (pcity=0x55555d7b4d40)
    at citydlg.c:499
#5  0x0000555555624d35 in create_city_dialog (pcity=0x55555d7b4d40)
    at citydlg.c:1661
#6  real_city_dialog_popup (pcity=0x55555d7b4d40) at citydlg.c:561
#7  0x000055555561494d in cities_update_callback (data=<optimized out>)
    at update_queue.c:608
#8  cities_update_callback (data=<optimized out>) at update_queue.c:581