Update dependency mypy to v1.16.0 (#8991)

Co-authored-by: Andrew Murray <radarhere@users.noreply.github.com>

Author: renovate[bot]

.ci/requirements-mypy.txt

@@ -1,4 +1,4 @@
-mypy==1.15.0
+mypy==1.16.0
 IceSpringPySideStubs-PyQt6
 IceSpringPySideStubs-PySide6
 ipython

Tests/test_file_jpeg.py

@@ -145,14 +145,16 @@ def test_cmyk(self) -> None:
             assert k > 0.9
             # roundtrip, and check again
             im = self.roundtrip(im)
-            c, m, y, k = (x / 255.0 for x in im.getpixel((0, 0)))
+            cmyk = im.getpixel((0, 0))
+            assert isinstance(cmyk, tuple)
+            c, m, y, k = (x / 255.0 for x in cmyk)
             assert c == 0.0
             assert m > 0.8
             assert y > 0.8
             assert k == 0.0
-            c, m, y, k = (
-                x / 255.0 for x in im.getpixel((im.size[0] - 1, im.size[1] - 1))
-            )
+            cmyk = im.getpixel((im.size[0] - 1, im.size[1] - 1))
+            assert isinstance(cmyk, tuple)
+            k = cmyk[3] / 255.0
             assert k > 0.9
 
     def test_rgb(self) -> None:

Tests/test_image.py

@@ -671,6 +671,7 @@ def test_remap_palette(self) -> None:
         im_remapped = im.remap_palette(list(range(256)))
         assert_image_equal(im, im_remapped)
         assert im.palette is not None
+        assert im_remapped.palette is not None
         assert im.palette.palette == im_remapped.palette.palette
 
         # Test illegal image mode

src/PIL/GifImagePlugin.py

@@ -31,7 +31,7 @@
 import subprocess
 from enum import IntEnum
 from functools import cached_property
-from typing import IO, Any, Literal, NamedTuple, Union
+from typing import IO, Any, Literal, NamedTuple, Union, cast
 
 from . import (
     Image,
@@ -350,12 +350,15 @@ def _rgb(color: int) -> tuple[int, int, int]:
             if self._frame_palette:
                 if color * 3 + 3 > len(self._frame_palette.palette):
                     color = 0
-                return tuple(self._frame_palette.palette[color * 3 : color * 3 + 3])
+                return cast(
+                    tuple[int, int, int],
+                    tuple(self._frame_palette.palette[color * 3 : color * 3 + 3]),
+                )
             else:
                 return (color, color, color)
 
         self.dispose = None
-        self.dispose_extent = frame_dispose_extent
+        self.dispose_extent: tuple[int, int, int, int] | None = frame_dispose_extent
         if self.dispose_extent and self.disposal_method >= 2:
             try:
                 if self.disposal_method == 2: