error

❯ g++ -fsanitize=undefined main.cpp -o main
❯ ./main
alignof T: 8
alignof T: 8
tmp.h:108:30: runtime error: member call on address 0x55fed14e8ed0 which does not point to an object of type 'ControlBlockBase'
0x55fed14e8ed0: note: object is of type 'SharedPtr<Data>::ControlBlockPtr'
 00 00 00 00  70 bc f6 d0 fe 55 00 00  01 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  b0 8e 4e d1
              ^~~~~~~~~~~~~~~~~~~~~~~
              vptr for 'SharedPtr<Data>::ControlBlockPtr'
tmp.h:28:15: runtime error: member access within address 0x55fed14e8ed0 which does not point to an object of type 'ControlBlockBase'
0x55fed14e8ed0: note: object is of type 'SharedPtr<Data>::ControlBlockPtr'
 00 00 00 00  70 bc f6 d0 fe 55 00 00  01 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  b0 8e 4e d1
              ^~~~~~~~~~~~~~~~~~~~~~~
              vptr for 'SharedPtr<Data>::ControlBlockPtr'
tmp.h:119:34: runtime error: member call on address 0x55fed14e8ed0 which does not point to an object of type 'ControlBlockBase'
0x55fed14e8ed0: note: object is of type 'SharedPtr<Data>::ControlBlockPtr'
 00 00 00 00  70 bc f6 d0 fe 55 00 00  02 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  b0 8e 4e d1
              ^~~~~~~~~~~~~~~~~~~~~~~
              vptr for 'SharedPtr<Data>::ControlBlockPtr'
tmp.h:128:34: runtime error: member call on address 0x55fed14e8ed0 which does not point to an object of type 'ControlBlockBase'
0x55fed14e8ed0: note: object is of type 'SharedPtr<Data>::ControlBlockPtr'
 00 00 00 00  70 bc f6 d0 fe 55 00 00  03 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  b0 8e 4e d1
              ^~~~~~~~~~~~~~~~~~~~~~~
              vptr for 'SharedPtr<Data>::ControlBlockPtr'

that's all