For instance this file:foo = f"""{}foo"""$ python3.8 --version --versionPython 3.8.0b1 (default, Jun  6 2019, 03:44:52) [GCC 7.4.0]$ python3.8 t.py | wc -c  File "t.py", line 1<<snipped, but very very many spaces>>                                   ^SyntaxError: f-string: empty expression not allowed$ python3.8 t.py |& wc -c49134

I can also trigger this with:```1+ """\q"""```And `python -Werror`so it seems not necessarily related to fstrings

Debugging further, there's a token with a `multi_line_start` pointing at uninitialized memory -- let's see if I can't track down where that gets set and fix it :)

This looks like the same issue I mentioned herehttps://bugs.python.org/msg344764

On Windows 10 with current 3.8 I see correct output, so the bug seems OS specific, even though the simple fix (see PR) is not.C:\Users\Terry>py f:/python/a/tem4.py  File "f:/python/a/tem4.py", line 1    f'''{}    ^SyntaxError: f-string: empty expression not allowed

just an f-string doesn't trigger this, there needs to be tokens before it

OK, very obnoxious.  Fix restores behavior above.

Thanks Anthony Sottile for the fix!I suggest adding more test cases that do not involve f-strings, what do you think? Can you create another PR for those?

sure! the only other case I could come up with involves multi-line strings and invalid escape sequences + Werrorlet me see if I can fold that in as well

This seems related. It's also possible I'm misunderstanding what is supposed to happen here.If you create test.py with just the 2 lines:"""aand run python test.py from CPython master, you get$./python.exe test.py  File "/Users/aaronmeurer/Documents/cpython/test.py", line 4    a    ^SyntaxError: EOF while scanning triple-quoted string literalNotice that it reports line 4 even though the file only has 2 lines.The offset in the syntax error is 6 columns (line numbers and column offsetsin SyntaxErrors count from 1)>>> try:...     compile('"""\na', '<none>', 'exec')... except SyntaxError as e:...     print(repr(e))...SyntaxError('EOF while scanning triple-quoted string literal', ('<none>', 2, 6, '"""\na\n'))

seems unrelated and does the same on older versions of python:```$ python3.5 t.py  File "t.py", line 4        ^SyntaxError: EOF while scanning triple-quoted string literal```I'd suggest a new issue or finding the dupe

The initial issue has been fixed in master by the commit5b94f3578c662d5f1ee90c0e6b81481d9ec82d89:commit5b94f3578c662d5f1ee90c0e6b81481d9ec82d89Author: Anthony Sottile <asottile@umich.edu>Date:   Mon Jul 29 06:59:13 2019 -0700    Fix `SyntaxError` indicator printing too many spaces for multi-line strings (GH-14433)Backport to 3.8: commitcf52bd0b9b1c1b7ecdd91e1ebebd15ae5c213a2c.Thanks Anthony Sottile! I close the issue.--If there is a different issue in Python 3.7 and you consider that it must be fixed, please file a new issue. Python 3.5 and 3.6 don't accept bugfixes anymore:https://devguide.python.org/#status-of-python-branches