mypy errors

zxlive/base_panel.py

@@ -54,12 +54,14 @@ def __init__(self, *actions: QAction) -> None:
 
         # Use box layout that fills the entire tab
         self.setLayout(QVBoxLayout())
-        self.layout().setSpacing(0)
+        layout = self.layout()
+        assert layout is not None # for mypy
+        layout.setSpacing(0)
         self.toolbar = QToolBar()
-        self.layout().addWidget(self.toolbar)
+        layout.addWidget(self.toolbar)
 
         self.splitter = QSplitter(self)
-        self.layout().addWidget(self.splitter)
+        layout.addWidget(self.splitter)
         self.splitter.splitterMoved.connect(self.sync_splitter_sizes)
 
         self.file_path = None

zxlive/editor_base_panel.py

@@ -327,6 +327,7 @@ def add_item(self, name: str) -> None:
             combobox.setCurrentIndex(0)
         combobox.currentTextChanged.connect(lambda text: self._text_changed(name, text))
         item = self._layout.itemAtPosition(2 + self._items, 2)
+        assert item is not None # For mypy
         self._layout.removeItem(item)
         self._layout.addWidget(QLabel(f"<pre>{name}</pre>"), 2 + self._items, 0, Qt.AlignmentFlag.AlignVCenter | Qt.AlignmentFlag.AlignRight)
         self._layout.addWidget(combobox, 2 + self._items, 2, Qt.AlignmentFlag.AlignCenter)

zxlive/mainwindow.py

@@ -63,8 +63,10 @@ def __init__(self) -> None:
         w = QWidget(self)
         w.setLayout(QVBoxLayout())
         self.setCentralWidget(w)
-        w.layout().setContentsMargins(0, 0, 0, 0)
-        w.layout().setSpacing(0)
+        wlayout = w.layout()
+        assert wlayout is not None # for mypy
+        wlayout.setContentsMargins(0, 0, 0, 0)
+        wlayout.setSpacing(0)
         self.resize(1200, 800)
 
         # restore the window from the last time it was opened
@@ -74,7 +76,7 @@ def __init__(self) -> None:
         self.show()
 
         tab_widget = QTabWidget(self)
-        w.layout().addWidget(tab_widget)
+        wlayout.addWidget(tab_widget)
         tab_widget.setTabsClosable(True)
         tab_widget.currentChanged.connect(self.tab_changed)
         tab_widget.tabCloseRequested.connect(self.close_tab)
@@ -339,7 +341,7 @@ def close_tab(self, i: int) -> bool:
             name = self.tab_widget.tabText(i).replace("*","")
             answer = QMessageBox.question(self, "Save Changes",
                             f"Do you wish to save your changes to {name} before closing?",
-                            QMessageBox.StandardButton.Yes | QMessageBox.StandardButton.No | QMessageBox.StandardButton.Cancel)
+                            QMessageBox.StandardButton.Yes | QMessageBox.StandardButton.No | QMessageBox.StandardButton.Cancel) # type: ignore
             if answer == QMessageBox.StandardButton.Cancel:
                 return False
             if answer == QMessageBox.StandardButton.Yes:
@@ -584,7 +586,7 @@ def format_str(c: complex) -> str:
         table.resizeColumnsToContents()
         table.resizeRowsToContents()
         dialog.setLayout(QVBoxLayout())
-        dialog.layout().addWidget(table)
+        dialog.layout().addWidget(table) # type: ignore # mypy thinks this can be None
         dialog.exec()
 
     def proof_as_lemma(self) -> None:

zxlive/vitem.py

@@ -307,7 +307,7 @@ def mouseReleaseEvent(self, e: QGraphicsSceneMouseEvent) -> None:
             e.ignore()
             return
         if e.button() == Qt.MouseButton.LeftButton:
-            if self._old_pos != self.pos():
+            if self._old_pos is None or self._old_pos != self.pos():
                 if self.ty == VertexType.W_INPUT:
                     # set the position of w_in to next to w_out at the same angle
                     w_out = get_w_partner_vitem(self)