typealias import

src/textual/__init__.py

@@ -4,10 +4,14 @@ import inspect
 
 import rich.repr
 from rich.console import RenderableType
+from typing import TYPE_CHECKING
 
 from ._context import active_app
 from ._log import LogGroup, LogVerbosity
-from ._typing import TypeAlias
+
+
+if TYPE_CHECKING:
+    from typing import Callable, TypeAlias
 
 __all__ = ["log", "panic", "__version__"]  # type: ignore
 

src/textual/_border.py

@@ -1,14 +1,16 @@
 from __future__ import annotations
 
 from functools import lru_cache
-from typing import cast, Tuple, Union
+from typing import cast, Tuple, TYPE_CHECKING, Union
 
 from rich.segment import Segment
 from rich.style import Style
 
 from .color import Color
 from .css.types import EdgeStyle, EdgeType
-from ._typing import TypeAlias
+
+if TYPE_CHECKING:
+    from typing import TypeAlias
 
 INNER = 1
 OUTER = 2

src/textual/_compositor.py

@@ -59,7 +59,7 @@ class MapGeometry(NamedTuple):
 
 
 # Maps a widget on to its geometry (information that describes its position in the composition)
-CompositorMap: TypeAlias = dict[Widget, MapGeometry]
+CompositorMap: TypeAlias = "dict[Widget, MapGeometry]"
 
 
 @rich.repr.auto(angular=True)