Can confirm on Python 3.12.0a5+ (heads/main:bcadcde712, Feb 26 2023, 12:54:46) [MSC v.1929 64 bit (AMD64)] on win32.

Note: Ā here is UTF8-encoded as C4 80 (a single U+0100 LATIN CAPITAL LETTER A WITH MACRON). So incorrect row advancing on combined code points is totally ruled out until text normalization happens inside the parser.

@benjaminp, @pablogsal (as parser experts)

update: @gvanrossum, @lysnikolaou (as new parser experts)

In IDLE, Python 3.12.0a5+ (heads/main:0f89acf6cc, Feb 27 2023, 21:33:28) says "incomplete input" for this and "\N{a}", reported in #102312, and marks the closing quote, but this is effect of how codeop compiles.
In REPL, I see the above and the #102312 message. I closed #102312 as duplicate.

Verified bug in installed 3.10.10, 3.11.2, and 3.12.a5.

What do you think about this?

» ./python.exe ex.py
  File "/Users/sobolev/Desktop/cpython/ex.py", line 1
    x = b"Ā"
        ^^^^^
SyntaxError: bytes can only contain ASCII literal characters

This can be achieved with:

Or do we need to highlight the symbol exactly?
If my solution is fine, I can add a test case and send a PR.

If my solution is fine, I can add a test case and send a PR.

@sobolevn In absence of other feedback, your solution looks better than nothing. So it's worth to create a PR and get it merged before 3.12b1.

Will do :)