Can't debug STL-containers when using _GLIBCXX_DEBUG.

{{
Can't debug standard containers when using _GLIBCXX_DEBUG.

Tested with: Qt-Creator 4.6.1, gcc 8.0.1, gdb 7.7.1

Short example:
============
#include <vector>
#include <iostream>

int main(int,char**) {
std::vector<int> nums =

{1,2,3,4,5,6,7,8,9,10}

;

// read past the end:
for(unsigned int i=0;i<=10;++i)
std::cout << nums[i] << " ";
std::cout << std::endl;
return 0; // breakpoint here
}
============
Prints (happily reads past the end):
1 2 3 4 5 6 7 8 9 10 132033

Debugging – locals window (correct):
Name | Value | Type
========================
nums | <10 items> | std::vector<int>
... the 10 values listed correctly.

---------------------------------------------------------------------------------
With

DEFINES += _GLIBCXX_DEBUG

in .pro file (Rebuild All !!!), this will print the following errors:

====
The inferior stopped because it received a signal from the operating system.

Signal name :
SIGABRT
Signal meaning :
Aborted

/usr/include/c++/8/debug/vector:417:
Error: attempt to subscript container with out-of-bounds index 10, but
container only holds 10 elements.

Objects involved in the operation:
sequence "this" @ 0x0x7ffd63d89800

{ type = std::__debug::vector<int, std::allocator<int> >; }

1 2 3 4 5 6 7 8 9 10
====

However, when debugging (breakpoint before the loop):
Name | Value | Type
========================
nums | <0 items> | std::vector<int>
(Internal Type: std::__debug::vector<int,std::allocator<int> >

Debugging of STL-containers now isn't possible anymore.

_GLIBCXX_DEBUG enables checks for invalid iterators, use-after-free, deadlocks (std locks only, obviously) and much more. It uses specific 'debug containers' for doing so. When debugging, it is usually preferable to turn this on.
I believe this bug had already been fixed in the past (Qt-Creator 2-somthing)...
}}