[Bug c++/125771] [13/14/15/16/17 Regression] Double destructor call during aggregate initialization with designated initializers when an exception is thrown.

[zheng.xianyuwang at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=125771

--- Comment #2 from Wang Jinghao <zheng.xianyuwang at gmail dot com> ---
split_nonconstant_init_1() recursively generates cleanup actions, while the
outermost split_nonconstant_init() appends statements that disable those
cleanups. The generated sequence is roughly as follows:

        construct a.b.c
        register cleanup for a.b.c
        [construct a.b]
        register cleanup for a.b
        throw
        disable cleanup for a.b
        disable cleanup for a.b.c

Therefore, on the exception path, execution never reaches the statements that
disable the cleanups. As a result, B::~B() and C::~C() are invoked in sequence,
causing the object to be destroyed twice.