Oh, I misunderstood something.
patched Python 3.7 and system's Python 3.5 shows same output for code below.
I'll check what is actually changed.
inada-n@x250 ~/w/p/ast-docstring> cat -n x.py
1 """module docstring"""
2
3 def func():
4 """func docstring"""
5
6 def func2():
7 """func docstring"""
8 1+1
9
10 print(func.__code__.co_firstlineno)
11 print(func.__code__.co_lnotab)
12 print(func2.__code__.co_firstlineno)
13 print(func2.__code__.co_lnotab)
inada-n@x250 ~/w/p/ast-docstring> ./python x.py
3
b''
6
b'\x00\x02'
inada-n@x250 ~/w/p/ast-docstring> /usr/bin/python3 x.py
3
b''
6
b'\x00\x02'