I found following inconsistency in the error message when there's a missing comma (it behaves that way both on main and 3.10).

Here's what happens with numbers, as expected:

Python 3.11.0a1+ (heads/main:32f55d1a5d, Nov  5 2021, 13:18:52) [GCC 11.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> 1 2 3 4
  File "<stdin>", line 1
    1 2 3 4
    ^^^
SyntaxError: invalid syntax. Perhaps you forgot a comma?

But with names the error is further right in the lines:

>>> a b c d
  File "<stdin>", line 1
    a b c d
      ^^^
SyntaxError: invalid syntax. Perhaps you forgot a comma?
>>> a b c d e f g
  File "<stdin>", line 1
    a b c d e f g
              ^^^
SyntaxError: invalid syntax. Perhaps you forgot a comma?

That looks potentially quite confusing to me?

(I don't know if these nit-picky parsing issues are too annoying, if they are please tell me to stop filing them).

>(I don't know if these nit-picky parsing issues are too annoying, if they are please tell me to stop filing them).

Don't worry, I think is great to discuss these cases. If there are too many, then maybe it will take a while to correct, but please, don't stop :)

> That looks potentially quite confusing to me?

I agree is unfortunate that is inconsistent, but unfortunately, this is going to be a bit of a pain because the way the expression rule is reached. I will try to see if we can easily fix this without having to restructure a bunch of the grammar

New changeset 546cefcda75d7150b55c8bc1724bea35a1e12890 by Pablo Galindo Salgado in branch 'main':
bpo-45727: Make the syntax error for missing comma more consistent (GH-29427)
https://github.com/python/cpython/commit/546cefcda75d7150b55c8bc1724bea35a1e12890

New changeset 511ee1c0fa4dedf32cc2b9f9fa13aa61e07bd165 by Pablo Galindo Salgado in branch '3.10':
[3.10] bpo-45727: Make the syntax error for missing comma more consistent (GH-29427) (GH-29647)
https://github.com/python/cpython/commit/511ee1c0fa4dedf32cc2b9f9fa13aa61e07bd165

New changeset 24c10d2943c482c4d3ecc71d45df2d8c10fa5bb1 by Pablo Galindo Salgado in branch 'main':
bpo-45727: Only trigger the 'did you forgot a comma' error suggestion if inside parentheses (GH-29757)
https://github.com/python/cpython/commit/24c10d2943c482c4d3ecc71d45df2d8c10fa5bb1

New changeset c72311d91787005713bb5daf4532a86e06496afd by Pablo Galindo Salgado in branch '3.10':
[3.10] bpo-45727: Only trigger the 'did you forgot a comma' error suggestion if inside parentheses. (GH-29767)
https://github.com/python/cpython/commit/c72311d91787005713bb5daf4532a86e06496afd