diff --git a/changelog.d/731.downstream.rst b/changelog.d/731.downstream.rst
new file mode 100644
index 00000000..3b19d48e
--- /dev/null
+++ b/changelog.d/731.downstream.rst
@@ -0,0 +1 @@
+Added pyright type-checking.
diff --git a/pytest_asyncio/plugin.py b/pytest_asyncio/plugin.py
index 9bfcfc64..5955bb0a 100644
--- a/pytest_asyncio/plugin.py
+++ b/pytest_asyncio/plugin.py
@@ -392,6 +392,7 @@ def _from_function(cls, function: Function, /) -> Function:
         Function item.
         """
         assert function.get_closest_marker("asyncio")
+        assert function.parent is not None
         subclass_instance = cls.from_parent(
             function.parent,
             name=function.name,
diff --git a/tox.ini b/tox.ini
index e6457f56..3608cc56 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,6 +1,6 @@
 [tox]
 minversion = 4.9.0
-envlist = py39, py310, py311, py312, py313, py314, pytest-min, docs
+envlist = py39, py310, py311, py312, py313, py314, pytest-min, docs, pyright
 isolated_build = true
 passenv =
     CI
@@ -69,12 +69,19 @@ passenv =
     SSH_AUTH_SOCK
 skip_install = false
 
+[testenv:pyright]
+deps =
+    pyright[nodejs]
+    pytest
+commands = pyright pytest_asyncio/
+skip_install = true
+
 [gh-actions]
 python =
     3.9: py39, pytest-min
     3.10: py310
     3.11: py311
     3.12: py312
-    3.13: py313
+    3.13: py313, pyright
     3.14-dev: py314
     pypy3: pypy3