This code generates an XML tree structure with 20001 nested elements, where each element is named 'x'. Initially, a root element named 'x' is created using xml.etree.cElementTree. Then, the for loop creates 20000 sub-elements of the root element. Each sub-element is also named 'x' and is created using the SubElement method. The variable y is assigned the last sub-element created. It is a reference to the deepest nested element in the tree. Finally, the variable x is deleted, which removes the reference to the root element. However, the y variable still holds the reference to the entire XML tree structure, including the root element and all of its sub-elements.

test.py

import xml.etree.cElementTree as ElementTree
y = x = ElementTree.Element('x')
for i in range(20000): 
    y = ElementTree.SubElement(y, 'x')
del x

Crash message:
Segmentation fault (core dumped)

Environment:
Ubuntu 18.04
rustpython v0.2.0