[BUG] ASAN Heap-after-use error

Stack trace:

READ of size 11 at 0x60600044ebf8 thread T0
    #0 0x7f0c509e1a6c  (/usr/lib/x86_64-linux-gnu/libasan.so.5+0x67a6c)
    #1 0x7f0c50655cd8 in PyUnicode_FromString (/usr/lib/x86_64-linux-gnu/libpython3.8.so.1.0+0x229cd8)
    #2 0x558bce5341bc in Jedi::AutoComplete(QString const&, long, long) (/home/harshit/expressPython-1/expressPython+0x9c1bc)
    #3 0x558bce50ac1d in CodeEditor::keyPressEvent(QKeyEvent*) (/home/harshit/expressPython-1/expressPython+0x72c1d)
    #4 0x7f0c4fec577c in QWidget::event(QEvent*) (/usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5+0x1ad77c)
    #5 0x7f0c4ff72d51 in QFrame::event(QEvent*) (/usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5+0x25ad51)
    #6 0x7f0c4ff759d0 in QAbstractScrollArea::event(QEvent*) (/usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5+0x25d9d0)
    #7 0x7f0c5004bab8 in QPlainTextEdit::event(QEvent*) (/usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5+0x333ab8)
    #8 0x7f0c4fe82a65 in QApplicationPrivate::notify_helper(QObject*, QEvent*) (/usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5+0x16aa65)
    #9 0x7f0c4fe8c81d in QApplication::notify(QObject*, QEvent*) (/usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5+0x17481d)
    #10 0x7f0c4f46a939 in QCoreApplication::notifyInternal2(QObject*, QEvent*) (/usr/lib/x86_64-linux-gnu/libQt5Core.so.5+0x286939)
    #11 0x7f0c4fee4215  (/usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5+0x1cc215)
    #12 0x7f0c4fe82a65 in QApplicationPrivate::notify_helper(QObject*, QEvent*) (/usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5+0x16aa65)
    #13 0x7f0c4fe8c0ef in QApplication::notify(QObject*, QEvent*) (/usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5+0x1740ef)
    #14 0x7f0c4f46a939 in QCoreApplication::notifyInternal2(QObject*, QEvent*) (/usr/lib/x86_64-linux-gnu/libQt5Core.so.5+0x286939)
    #15 0x7f0c4f84fb2a in QGuiApplicationPrivate::processKeyEvent(QWindowSystemInterfacePrivate::KeyEvent*) (/usr/lib/x86_64-linux-gnu/libQt5Gui.so.5+0x122b2a)
    #16 0x7f0c4f8550f0 in QGuiApplicationPrivate::processWindowSystemEvent(QWindowSystemInterfacePrivate::WindowSystemEvent*) (/usr/lib/x86_64-linux-gnu/libQt5Gui.so.5+0x1280f0)
    #17 0x7f0c4f82f35a in QWindowSystemInterface::sendWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) (/usr/lib/x86_64-linux-gnu/libQt5Gui.so.5+0x10235a)
    #18 0x7f0c48a7432d  (/usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5+0x7932d)
    #19 0x7f0c4e3b4fbc in g_main_context_dispatch (/usr/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x51fbc)
    #20 0x7f0c4e3b523f  (/usr/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x5223f)
    #21 0x7f0c4e3b52e2 in g_main_context_iteration (/usr/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x522e2)
    #22 0x7f0c4f4c2564 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (/usr/lib/x86_64-linux-gnu/libQt5Core.so.5+0x2de564)
    #23 0x7f0c4f4694da in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (/usr/lib/x86_64-linux-gnu/libQt5Core.so.5+0x2854da)
    #24 0x7f0c4f471245 in QCoreApplication::exec() (/usr/lib/x86_64-linux-gnu/libQt5Core.so.5+0x28d245)
    #25 0x558bce4bb5f6 in main (/home/harshit/expressPython-1/expressPython+0x235f6)
    #26 0x7f0c4ee1b0b2 in __libc_start_main (/usr/lib/x86_64-linux-gnu/libc.so.6+0x270b2)
    #27 0x558bce4bbd4d in _start (/home/harshit/expressPython-1/expressPython+0x23d4d)

0x60600044ebf8 is located 24 bytes inside of 64-byte region [0x60600044ebe0,0x60600044ec20)
freed by thread T0 here:
    #0 0x7f0c50a877cf in __interceptor_free (/usr/lib/x86_64-linux-gnu/libasan.so.5+0x10d7cf)
    #1 0x558bce53478c in Jedi::AutoComplete(QString const&, long, long) (/home/harshit/expressPython-1/expressPython+0x9c78c)
    #2 0x558bce50ac1d in CodeEditor::keyPressEvent(QKeyEvent*) (/home/harshit/expressPython-1/expressPython+0x72c1d)
    #3 0x7f0c4fec577c in QWidget::event(QEvent*) (/usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5+0x1ad77c)

previously allocated by thread T0 here:
    #0 0x7f0c50a87ffe in __interceptor_realloc (/usr/lib/x86_64-linux-gnu/libasan.so.5+0x10dffe)
    #1 0x7f0c4f2ae2df in QArrayData::reallocateUnaligned(QArrayData*, unsigned long, unsigned long, QFlags<QArrayData::AllocationOption>) (/usr/lib/x86_64-linux-gnu/libQt5Core.so.5+0xca2df)

SUMMARY: AddressSanitizer: heap-use-after-free (/usr/lib/x86_64-linux-gnu/libasan.so.5+0x67a6c) 
Shadow bytes around the buggy address:
  0x0c0c80081d20: fa fa fa fa fa fa fa fa fd fd fd fd fd fd fd fd
  0x0c0c80081d30: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c0c80081d40: fd fd fd fd fd fd fd fd fa fa fa fa fd fd fd fd
  0x0c0c80081d50: fd fd fd fd fa fa fa fa fd fd fd fd fd fd fd fd
  0x0c0c80081d60: fa fa fa fa fd fd fd fd fd fd fd fd fa fa fa fa
=>0x0c0c80081d70: fa fa fa fa fa fa fa fa fa fa fa fa fd fd fd[fd]
  0x0c0c80081d80: fd fd fd fd fa fa fa fa fd fd fd fd fd fd fd fa
  0x0c0c80081d90: fa fa fa fa fd fd fd fd fd fd fd fa fa fa fa fa
  0x0c0c80081da0: fd fd fd fd fd fd fd fa fa fa fa fa fd fd fd fd
  0x0c0c80081db0: fd fd fd fa fa fa fa fa 00 00 00 00 00 00 00 00
  0x0c0c80081dc0: fa fa fa fa fd fd fd fd fd fd fd fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07 
  Heap left redzone:       fa
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
  Left alloca redzone:     ca
  Right alloca redzone:    cb
  Shadow gap:              cc
==667729==ABORTING```

Start with Jedi::AutoComplete and CodeEditor::keyPressEvent, the application frames identified by the AddressSanitizer trace. Reproduce the heap-use-after-free under ASAN and trace the allocation, free, and subsequent read. Done means the reported use-after-free no longer occurs during the affected editor interaction.