deleting member of state in destructor of nest loop join causing error

[fzhedu]

when deleting member of state (e.t state_.child_left, state_.child_right...) in destructor of nest loop join causing error:

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7fff86c1c700 (LWP 8212)]
SLL_PopRange (end=, start=, N=819,
head=0x1db6a60) at src/linked_list.h:76
76 tmp = SLL_Next(tmp);

but the code doesn't have bug, and when change the code with other form, but new bug occurs in other place.
so what's the essence ?