Wrong return type detected for @overload function

In the scenario where a @overload function is called, mypy doesn't reliably detect the correct return value.

I'm using the following code to call PySide6 functions:

gearIcon = QIcon(str('...'))
menuSettings: QMenu = self.menuBar().addMenu('&Tools')
actionSettings = menuSettings.addAction(gearIcon, '&Settings')
actionSettings.triggered.connect(self.showSettingsDialog)

mypy assumes addAction to return None and notes the following error:

error: "None" has no attribute "triggered"

The QtWidgets.pyi includes the following type declaration:

@typing.overload
def addAction(self, arg__1:PySide6.QtGui.QAction) -> None: ...
@typing.overload
def addAction(self, arg__1:PySide6.QtGui.QIcon, arg__2:str, arg__3:object, arg__4:typing.Optional[PySide6.QtGui.QKeySequence]=...) -> None: ...
@typing.overload
def addAction(self, arg__1:str, arg__2:object, arg__3:typing.Optional[PySide6.QtGui.QKeySequence]=...) -> None: ...
@typing.overload
def addAction(self, icon:PySide6.QtGui.QIcon, text:str) -> PySide6.QtGui.QAction: ...
@typing.overload
def addAction(self, icon:PySide6.QtGui.QIcon, text:str, receiver:PySide6.QtCore.QObject, member:bytes, shortcut:PySide6.QtGui.QKeySequence=...) -> PySide6.QtGui.QAction: ...
@typing.overload
def addAction(self, text:str) -> PySide6.QtGui.QAction: ...
@typing.overload
def addAction(self, text:str, receiver:PySide6.QtCore.QObject, member:bytes, shortcut:PySide6.QtGui.QKeySequence=...) -> PySide6.QtGui.QAction: ...

The overloaded addAction function that "best" (and exactly) matches the arguments (QIcon, str) is defined to return QAction. The None returning variants don't match the argument list, so they should not be considered.

The documentation states:

When you call an overloaded function, mypy will infer the correct return type by picking the best matching variant, after taking into consideration both the argument types and arity.
...
If there are multiple equally good matching variants, mypy will select the variant that was defined first. 

Your Environment

• Mypy version used: 0.800 (same behavior in 0.790)
• Python version used: 3.9.1

まず、提供された PySide6 のオーバーロードと mypy 0.800 を使って報告された呼び出しを再現し、次に mypy が QtWidgets.pyi の宣言に対してオーバーロードされた呼び出しをどのようにチェックするかを調べます。(QIcon, str) の呼び出しが None ではなく QAction を返すと推論され、その例を対象とするリグレッションテストがある状態を完了とします。