From 85dbd2d767418799c5238e4a16a6afcdf7dcaf46 Mon Sep 17 00:00:00 2001
From: "Miss Islington (bot)"
 <31488909+miss-islington@users.noreply.github.com>
Date: Tue, 22 Nov 2022 03:03:26 -0800
Subject: [PATCH] gh-99341: Cover type ignore nodes when incrementing line
 numbers (GH-99422)

(cherry picked from commit 1acdfec359fdf3db936168480be0f4157273c200)

Co-authored-by: Batuhan Taskaya <isidentical@gmail.com>
---
 Lib/ast.py                                           |  6 ++++++
 Lib/test/test_ast.py                                 | 12 ++++++++++++
 .../2022-11-13-02-06-56.gh-issue-99341.8-OlwB.rst    |  2 ++
 3 files changed, 20 insertions(+)
 create mode 100644 Misc/NEWS.d/next/Library/2022-11-13-02-06-56.gh-issue-99341.8-OlwB.rst

diff --git a/Lib/ast.py b/Lib/ast.py
index 8c10d08002202c..623b9a1b805d0e 100644
--- a/Lib/ast.py
+++ b/Lib/ast.py
@@ -236,6 +236,12 @@ def increment_lineno(node, n=1):
     location in a file.
     """
     for child in walk(node):
+        # TypeIgnore is a special case where lineno is not an attribute
+        # but rather a field of the node itself.
+        if isinstance(child, TypeIgnore):
+            child.lineno = getattr(child, 'lineno', 0) + n
+            continue
+
         if 'lineno' in child._attributes:
             child.lineno = getattr(child, 'lineno', 0) + n
         if (
diff --git a/Lib/test/test_ast.py b/Lib/test/test_ast.py
index 90ad6af56fdb20..7581adc8fc272b 100644
--- a/Lib/test/test_ast.py
+++ b/Lib/test/test_ast.py
@@ -1026,6 +1026,18 @@ def test_increment_lineno(self):
         self.assertEqual(ast.increment_lineno(src).lineno, 2)
         self.assertIsNone(ast.increment_lineno(src).end_lineno)
 
+    def test_increment_lineno_on_module(self):
+        src = ast.parse(dedent("""\
+        a = 1
+        b = 2 # type: ignore
+        c = 3
+        d = 4 # type: ignore@tag
+        """), type_comments=True)
+        ast.increment_lineno(src, n=5)
+        self.assertEqual(src.type_ignores[0].lineno, 7)
+        self.assertEqual(src.type_ignores[1].lineno, 9)
+        self.assertEqual(src.type_ignores[1].tag, '@tag')
+
     def test_iter_fields(self):
         node = ast.parse('foo()', mode='eval')
         d = dict(ast.iter_fields(node.body))
diff --git a/Misc/NEWS.d/next/Library/2022-11-13-02-06-56.gh-issue-99341.8-OlwB.rst b/Misc/NEWS.d/next/Library/2022-11-13-02-06-56.gh-issue-99341.8-OlwB.rst
new file mode 100644
index 00000000000000..451561c579daff
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2022-11-13-02-06-56.gh-issue-99341.8-OlwB.rst
@@ -0,0 +1,2 @@
+Fix :func:`ast.increment_lineno` to also cover :class:`ast.TypeIgnore` when
+changing line numbers.