This patch fixes test failure related to reported source code locations.
It is a backport of this patch:

  commit 6a5f38b5ab12260fde8a0463acd433bc2d34dbcf
  Author: Louis Sautier <sautier.louis@gmail.com>
  Date:   Sat Oct 3 02:37:53 2020 +0200

      Fix tests with Python 3.9, closes #549 (#586)

      Stop allowing failures on Python nightly.

diff --git a/pyflakes/test/test_api.py b/pyflakes/test/test_api.py
index 128aa69..b728e65 100644
--- a/pyflakes/test/test_api.py
+++ b/pyflakes/test/test_api.py
@@ -515,6 +515,8 @@ def foo(bar=baz, bax):
             if ERROR_HAS_LAST_LINE:
                 if PYPY and sys.version_info >= (3,):
                     column = 7
+                elif sys.version_info >= (3, 9):
+                    column = 21
                 elif sys.version_info >= (3, 8):
                     column = 9
                 else:
@@ -543,6 +545,8 @@ foo(bar=baz, bax)
             if ERROR_HAS_LAST_LINE:
                 if PYPY and sys.version_info >= (3,):
                     column = 12
+                elif sys.version_info >= (3, 9):
+                    column = 17
                 elif sys.version_info >= (3, 8):
                     column = 14
                 else:
@@ -577,6 +581,8 @@ foo(bar=baz, bax)
                 position_end = 1
                 if PYPY:
                     column = 6
+                elif ver >= (3, 9):
+                    column = 13
                 else:
                     column = 7
                     # Column has been "fixed" since 3.2.4 and 3.3.1
et' action='/guix/log/tests/guix-daemon.sh'>
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<div class='path'>path: <a href='/guix/log/?id=01d7ce85c89bc25876538f191be6bed4226d1593'>root</a>/<a href='/guix/log/tests?id=01d7ce85c89bc25876538f191be6bed4226d1593'>tests</a>/<a href='/guix/log/tests/guix-daemon.sh?id=01d7ce85c89bc25876538f191be6bed4226d1593'>guix-daemon.sh</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/tests/guix-daemon.sh?id=01d7ce85c89bc25876538f191be6bed4226d1593&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2023-04-21 16:16:38 +0200'>2023-04-21</span></td><td><a href='/guix/commit/tests/guix-daemon.sh?id=37dd69b44511dc73eb04bdebe8d82c9a0386338e'>tests: Fix checks for expected failures.</a><span class='msg-avail'>...<span class='msg-tooltip'>Addresses &lt;https://issues.guix.gnu.org/62406&gt;.

With 'set -e', a return status inverted with '!' does not cause the shell to
exit immediately.  Instead use '&amp;&amp; false' to indicate an expected failure.

* tests/guix-archive.sh, tests/guix-build-branch.sh, tests/guix-build.sh,
tests/guix-daemon.sh, tests/guix-download.sh,
tests/guix-environment-container.sh, tests/guix-environment.sh,
tests/guix-gc.sh, tests/guix-git-authenticate.sh, tests/guix-graph.sh,
tests/guix-hash.sh, tests/guix-home.sh, tests/guix-pack-relocatable.sh,
tests/guix-pack.sh, tests/guix-package-aliases.sh, tests/guix-package-net.sh,
tests/guix-package.sh, tests/guix-refresh.sh, tests/guix-shell.sh,
tests/guix-style.sh, tests/guix-system.sh: Replace uses of '! ...' with
'... &amp;&amp; false' or `test ! ...` as appropriate.

Signed-off-by: Ludovic Courtès &lt;ludo@gnu.org&gt;
</span></span></td><td>Eric Bavier</td></tr>
<tr><td><span title='2022-10-22 01:46:55 +0200'>2022-10-22</span></td><td><a href='/guix/commit/tests/guix-daemon.sh?id=a3619079f95213c4f983e69210ed12b38fd31022'>Remove now unnecessary uses of (guix grafts).</a><span class='msg-avail'>...<span class='msg-tooltip'>These modules would use (guix grafts) just to access '%graft?' and
related bindings, which are now in (guix store).

* gnu/ci.scm,
guix/gexp.scm,
guix/lint.scm,
guix/scripts.scm,
guix/scripts/archive.scm,
guix/scripts/build.scm,
guix/scripts/challenge.scm,
guix/scripts/deploy.scm,
guix/scripts/environment.scm,
guix/scripts/home.scm,
guix/scripts/pack.scm,
guix/scripts/package.scm,
guix/scripts/pull.scm,
guix/scripts/size.scm,
guix/scripts/system.scm,
guix/scripts/weather.scm,
tests/builders.scm,
tests/channels.scm,
tests/cpan.scm,
tests/derivations.scm,
tests/gexp.scm,
tests/graph.scm,
tests/guix-daemon.sh,
tests/monads.scm,
tests/pack.scm,
tests/packages.scm,
tests/profiles.scm,
tests/system.scm: Remove #:use-module (guix grafts).
</span></span></td><td>Ludovic Courtès</td></tr>