A few linting fixes

Add some Python 3.8 type: ignores; all are already fixed in the next
mypy release, so can be removed once we upgrade.

Also move some flake8 ignores which seem to have changed places.

src/_pytest/_code/source.py

@@ -60,7 +60,7 @@ class Source:
         raise NotImplementedError()
 
     @overload  # noqa: F811
-    def __getitem__(self, key: slice) -> "Source":
+    def __getitem__(self, key: slice) -> "Source":  # noqa: F811
         raise NotImplementedError()
 
     def __getitem__(self, key: Union[int, slice]) -> Union[str, "Source"]:  # noqa: F811

src/_pytest/assertion/rewrite.py

@@ -1074,13 +1074,14 @@ def try_makedirs(cache_dir) -> bool:
 
 def get_cache_dir(file_path: Path) -> Path:
     """Returns the cache directory to write .pyc files for the given .py file path"""
-    if sys.version_info >= (3, 8) and sys.pycache_prefix:
+    # Type ignored until added in next mypy release.
+    if sys.version_info >= (3, 8) and sys.pycache_prefix:  # type: ignore
         # given:
         #   prefix = '/tmp/pycs'
         #   path = '/home/user/proj/test_app.py'
         # we want:
         #   '/tmp/pycs/home/user/proj'
-        return Path(sys.pycache_prefix) / Path(*file_path.parts[1:-1])
+        return Path(sys.pycache_prefix) / Path(*file_path.parts[1:-1])  # type: ignore
     else:
         # classic pycache directory
         return file_path.parent / "__pycache__"

src/_pytest/compat.py

@@ -40,7 +40,8 @@ MODULE_NOT_FOUND_ERROR = (
 
 
 if sys.version_info >= (3, 8):
-    from importlib import metadata as importlib_metadata  # noqa: F401
+    # Type ignored until next mypy release.
+    from importlib import metadata as importlib_metadata  # type: ignore
 else:
     import importlib_metadata  # noqa: F401
 
@@ -407,7 +408,9 @@ else:
             raise NotImplementedError()
 
         @overload  # noqa: F811
-        def __get__(self, instance: _S, owner: Optional["Type[_S]"] = ...) -> _T:
+        def __get__(  # noqa: F811
+            self, instance: _S, owner: Optional["Type[_S]"] = ...
+        ) -> _T:
             raise NotImplementedError()
 
         def __get__(self, instance, owner=None):  # noqa: F811

src/_pytest/python_api.py

@@ -552,7 +552,7 @@ def raises(
 
 
 @overload  # noqa: F811
-def raises(
+def raises(  # noqa: F811
     expected_exception: Union["Type[_E]", Tuple["Type[_E]", ...]],
     func: Callable,
     *args: Any,

src/_pytest/recwarn.py

@@ -60,18 +60,18 @@ def warns(
     *,
     match: "Optional[Union[str, Pattern]]" = ...
 ) -> "WarningsChecker":
-    ...  # pragma: no cover
+    raise NotImplementedError()
 
 
 @overload  # noqa: F811
-def warns(
+def warns(  # noqa: F811
     expected_warning: Union["Type[Warning]", Tuple["Type[Warning]", ...]],
     func: Callable,
     *args: Any,
     match: Optional[Union[str, "Pattern"]] = ...,
     **kwargs: Any
 ) -> Union[Any]:
-    ...  # pragma: no cover
+    raise NotImplementedError()
 
 
 def warns(  # noqa: F811