fix tooltip binding loop on _shown via assignedScreen mirror

nix/plugin.nix

@@ -1,6 +1,7 @@
 {
   lib,
   craneLib,
+  mold,
   pkg-config,
   qt6,
   writeShellScript,
@@ -67,6 +68,7 @@ let
 
     nativeBuildInputs = [
       pkg-config
+      mold
       qt6.qtbase
       qt6.qtdeclarative
     ];
@@ -79,8 +81,12 @@ let
 
     # qt6.qtbase's setup hook overrides QMAKE after derivation attrs are set,
     # so re-assert it in preBuild which runs after all setup hooks.
+    # Force mold as the linker (cxx-qt book deprecates ld.gold). Setting via
+    # CARGO_TARGET_*_LINKER + RUSTFLAGS is the only path that survives nixpkgs'
+    # cc-wrapper - `-fuse-ld=` from build.rs gets eaten by the wrapper.
     preBuild = ''
       export QMAKE=${qmakeWrapper}
+      export RUSTFLAGS="-C link-arg=-fuse-ld=mold ''${RUSTFLAGS:-}"
     '';
   };
 

shell/modules/Tooltip.qml

@@ -11,8 +11,13 @@ PanelWindow {
     visible: _winVisible
     color: "transparent"
 
+    // Mirror of `screen` captured at construction. Reading `root.screen`
+    // directly in `_shown` couples it to visibility transitions (PanelWindow
+    // re-evaluates `screen` when mapped/unmapped), which feeds back into
+    // `_shown` via `_winVisible` and trips a binding loop.
+    property var assignedScreen: null
     property bool _winVisible: false
-    property bool _shown: M.TooltipState.visible && M.TooltipState.screen === root.screen
+    property bool _shown: M.TooltipState.visible && M.TooltipState.screen === assignedScreen
 
     on_ShownChanged: {
         if (_shown) {

shell/shell.qml

@@ -33,6 +33,7 @@ ShellRoot {
 
             Tooltip {
                 screen: scope.modelData
+                assignedScreen: scope.modelData
             }
 
             LazyLoader {