Ronald Oussoren: The following code will crash hard when compiled using ARC: #import <Foundation/Foundation.h> int main(void) { NSOutputStream* stream; stream = [NSOutputStream alloc]; stream = [stream initToMemory]; NSLog(@"%@", stream); } This is split calls to alloc and initToMemory are effectively what happens when using NSOutputStream.alloc().initToMemory() in Python. […] This appears to be a genuine bug […]