diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 4f379968e..dc3717204 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -18,7 +18,7 @@ repos:
         args: [--remove]
     -   id: check-yaml
     -   id: debug-statements
-        exclude: _pytest/debugging.py
+        exclude: _pytest/(debugging|hookspec).py
         language_version: python3
 -   repo: https://gitlab.com/pycqa/flake8
     rev: 3.8.2
diff --git a/src/_pytest/debugging.py b/src/_pytest/debugging.py
index 423b20ce3..3001db4ec 100644
--- a/src/_pytest/debugging.py
+++ b/src/_pytest/debugging.py
@@ -2,6 +2,9 @@
 import argparse
 import functools
 import sys
+from typing import Generator
+from typing import Tuple
+from typing import Union
 
 from _pytest import outcomes
 from _pytest.compat import TYPE_CHECKING
@@ -15,10 +18,11 @@ from _pytest.nodes import Node
 from _pytest.reports import BaseReport
 
 if TYPE_CHECKING:
+    from _pytest.capture import CaptureManager
     from _pytest.runner import CallInfo
 
 
-def _validate_usepdb_cls(value):
+def _validate_usepdb_cls(value: str) -> Tuple[str, str]:
     """Validate syntax of --pdbcls option."""
     try:
         modname, classname = value.split(":")
@@ -70,7 +74,7 @@ def pytest_configure(config: Config) -> None:
 
     # NOTE: not using pytest_unconfigure, since it might get called although
     #       pytest_configure was not (if another plugin raises UsageError).
-    def fin():
+    def fin() -> None:
         (
             pdb.set_trace,
             pytestPDB._pluginmanager,
@@ -90,13 +94,13 @@ class pytestPDB:
     _wrapped_pdb_cls = None
 
     @classmethod
-    def _is_capturing(cls, capman):
+    def _is_capturing(cls, capman: "CaptureManager") -> Union[str, bool]:
         if capman:
             return capman.is_capturing()
         return False
 
     @classmethod
-    def _import_pdb_cls(cls, capman):
+    def _import_pdb_cls(cls, capman: "CaptureManager"):
         if not cls._config:
             import pdb
 
@@ -135,10 +139,12 @@ class pytestPDB:
         return wrapped_cls
 
     @classmethod
-    def _get_pdb_wrapper_class(cls, pdb_cls, capman):
+    def _get_pdb_wrapper_class(cls, pdb_cls, capman: "CaptureManager"):
         import _pytest.config
 
-        class PytestPdbWrapper(pdb_cls):
+        # Type ignored because mypy doesn't support "dynamic"
+        # inheritance like this.
+        class PytestPdbWrapper(pdb_cls):  # type: ignore[valid-type,misc] # noqa: F821
             _pytest_capman = capman
             _continued = False
 
@@ -257,7 +263,7 @@ class pytestPDB:
         return _pdb
 
     @classmethod
-    def set_trace(cls, *args, **kwargs):
+    def set_trace(cls, *args, **kwargs) -> None:
         """Invoke debugging via ``Pdb.set_trace``, dropping any IO capturing."""
         frame = sys._getframe().f_back
         _pdb = cls._init_pdb("set_trace", *args, **kwargs)
@@ -276,14 +282,14 @@ class PdbInvoke:
             sys.stdout.write(err)
         _enter_pdb(node, call.excinfo, report)
 
-    def pytest_internalerror(self, excrepr, excinfo):
+    def pytest_internalerror(self, excrepr, excinfo) -> None:
         tb = _postmortem_traceback(excinfo)
         post_mortem(tb)
 
 
 class PdbTrace:
     @hookimpl(hookwrapper=True)
-    def pytest_pyfunc_call(self, pyfuncitem):
+    def pytest_pyfunc_call(self, pyfuncitem) -> Generator[None, None, None]:
         wrap_pytest_function_for_tracing(pyfuncitem)
         yield
 
@@ -358,7 +364,7 @@ def _postmortem_traceback(excinfo):
         return excinfo._excinfo[2]
 
 
-def post_mortem(t):
+def post_mortem(t) -> None:
     p = pytestPDB._init_pdb("post_mortem")
     p.reset()
     p.interaction(None, t)
diff --git a/src/_pytest/faulthandler.py b/src/_pytest/faulthandler.py
index 79936b78f..0d969840b 100644
--- a/src/_pytest/faulthandler.py
+++ b/src/_pytest/faulthandler.py
@@ -99,7 +99,7 @@ class FaultHandlerHooks:
             yield
 
     @pytest.hookimpl(tryfirst=True)
-    def pytest_enter_pdb(self):
+    def pytest_enter_pdb(self) -> None:
         """Cancel any traceback dumping due to timeout before entering pdb.
         """
         import faulthandler
diff --git a/src/_pytest/hookspec.py b/src/_pytest/hookspec.py
index 99f646bd6..bcc38f472 100644
--- a/src/_pytest/hookspec.py
+++ b/src/_pytest/hookspec.py
@@ -15,7 +15,9 @@ from .deprecated import WARNING_CAPTURED_HOOK
 from _pytest.compat import TYPE_CHECKING
 
 if TYPE_CHECKING:
+    import pdb
     import warnings
+
     from _pytest.config import Config
     from _pytest.config import ExitCode
     from _pytest.config import PytestPluginManager
@@ -773,7 +775,7 @@ def pytest_exception_interact(
     """
 
 
-def pytest_enter_pdb(config: "Config", pdb):
+def pytest_enter_pdb(config: "Config", pdb: "pdb.Pdb") -> None:
     """ called upon pdb.set_trace(), can be used by plugins to take special
     action just before the python debugger enters in interactive mode.
 
@@ -782,7 +784,7 @@ def pytest_enter_pdb(config: "Config", pdb):
     """
 
 
-def pytest_leave_pdb(config: "Config", pdb):
+def pytest_leave_pdb(config: "Config", pdb: "pdb.Pdb") -> None:
     """ called when leaving pdb (e.g. with continue after pdb.set_trace()).
 
     Can be used by plugins to take special action just after the python