Got runtime error with compilation flag -fsanitize=undefined

[Ioann44]

Title says it all, if I use this compilation on gnu, then I got this on execution

runtime error: downcast of address 0x55555557ef38 which does not point to an object of type 'AbstractLine'
0x55555557ef38: note: object has invalid vptr
 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00
              ^~~~~~~~~~~~~~~~~~~~~~~
              invalid vptr