Work around issues with derive(Default)

src/app/mod.rs

@@ -478,7 +478,7 @@ where
     }
 
     /// Allows COSMIC to integrate with your application's [`nav_bar::Model`].
-    fn nav_model(&self) -> Option<&nav_bar::Model> {
+    fn nav_model(&self) -> Option<&nav_bar::Model<Message<Self::Message>>> {
         None
     }
 

src/widget/color_picker/mod.rs

@@ -62,9 +62,9 @@ pub enum ColorPickerUpdate {
 }
 
 #[derive(Setters)]
-pub struct ColorPickerModel {
+pub struct ColorPickerModel<Message> {
     #[setters(skip)]
-    segmented_model: Model<SingleSelect>,
+    segmented_model: Model<SingleSelect, Message>,
     #[setters(skip)]
     active_color: palette::Hsv,
     #[setters(skip)]
@@ -86,7 +86,7 @@ pub struct ColorPickerModel {
     copied_at: Option<Instant>,
 }
 
-impl ColorPickerModel {
+impl<Message> ColorPickerModel<Message> {
     #[must_use]
     pub fn new(
         hex: impl Into<Cow<'static, str>> + Clone,
@@ -118,11 +118,11 @@ impl ColorPickerModel {
 
     /// Get a color picker button that displays the applied color
     ///
-    pub fn picker_button<'a, Message: 'static, T: Fn(ColorPickerUpdate) -> Message>(
+    pub fn picker_button<'a, T: Fn(ColorPickerUpdate) -> Message>(
         &self,
         f: T,
         icon_portion: Option<u16>,
-    ) -> crate::widget::Button<'a, Message, crate::Theme, crate::Renderer> {
+    ) -> crate::widget::Button<'a, Message, crate::Theme, crate::Renderer> where Message: 'static {
         color_button(
             Some(f(ColorPickerUpdate::ToggleColorPicker)),
             self.applied_color,
@@ -130,7 +130,7 @@ impl ColorPickerModel {
         )
     }
 
-    pub fn update<Message>(&mut self, update: ColorPickerUpdate) -> Command<Message> {
+    pub fn update(&mut self, update: ColorPickerUpdate) -> Command<Message> {
         match update {
             ColorPickerUpdate::ActiveColor(c) => {
                 self.must_clear_cache.store(true, Ordering::SeqCst);
@@ -222,7 +222,7 @@ impl ColorPickerModel {
     }
 
     #[must_use]
-    pub fn builder<Message>(
+    pub fn builder(
         &self,
         on_update: fn(ColorPickerUpdate) -> Message,
     ) -> ColorPickerBuilder<Message> {
@@ -246,7 +246,7 @@ impl ColorPickerModel {
 #[derive(Setters, Clone)]
 pub struct ColorPickerBuilder<'a, Message> {
     #[setters(skip)]
-    model: &'a Model<SingleSelect>,
+    model: &'a Model<SingleSelect, Message>,
     #[setters(skip)]
     active_color: palette::Hsv,
     #[setters(skip)]

src/widget/nav_bar.rs

@@ -18,13 +18,13 @@ use crate::{theme, Theme};
 use super::dnd_destination::DragId;
 
 pub type Id = segmented_button::Entity;
-pub type Model = segmented_button::SingleSelectModel;
+pub type Model<Message> = segmented_button::SingleSelectModel<Message>;
 
 /// Navigation side panel for switching between views.
 ///
 /// For details on the model, see the [`segmented_button`] module for more details.
 pub fn nav_bar<Message: Clone + 'static>(
-    model: &segmented_button::SingleSelectModel,
+    model: &Model<Message>,
     on_activate: fn(segmented_button::Entity) -> Message,
 ) -> NavBar<Message> {
     NavBar {
@@ -35,7 +35,7 @@ pub fn nav_bar<Message: Clone + 'static>(
 /// Navigation side panel for switching between views.
 /// Can receive drag and drop events.
 pub fn nav_bar_dnd<Message, D: AllowedMimeTypes>(
-    model: &segmented_button::SingleSelectModel,
+    model: &Model<Message>,
     on_activate: fn(segmented_button::Entity) -> Message,
     on_dnd_enter: impl Fn(segmented_button::Entity, Vec<String>) -> Message + 'static,
     on_dnd_leave: impl Fn(segmented_button::Entity) -> Message + 'static,

src/widget/segmented_button/horizontal.rs

@@ -22,10 +22,10 @@ pub struct Horizontal;
 ///
 /// For details on the model, see the [`segmented_button`](super) module for more details.
 pub fn horizontal<SelectionMode: Default, Message>(
-    model: &Model<SelectionMode>,
+    model: &Model<SelectionMode, Message>,
 ) -> SegmentedButton<Horizontal, SelectionMode, Message>
 where
-    Model<SelectionMode>: Selectable,
+    Model<SelectionMode, Message>: Selectable,
 {
     SegmentedButton::new(model)
 }
@@ -33,7 +33,7 @@ where
 impl<'a, SelectionMode, Message> SegmentedVariant
     for SegmentedButton<'a, Horizontal, SelectionMode, Message>
 where
-    Model<SelectionMode>: Selectable,
+    Model<SelectionMode, Message>: Selectable,
     SelectionMode: Default,
 {
     fn variant_appearance(

src/widget/segmented_button/model/builder.rs

@@ -8,38 +8,44 @@ use crate::widget::icon::Icon;
 use std::borrow::Cow;
 
 /// A builder for a [`Model`].
-#[derive(Default)]
+pub struct ModelBuilder<SelectionMode: Default, Message>(Model<SelectionMode, Message>);
-pub struct ModelBuilder<SelectionMode: Default>(Model<SelectionMode>);
+
+//TODO: Default derive ends up requiring Message to implement Default
+impl<SelectionMode: Default, Message> Default for ModelBuilder<SelectionMode, Message> {
+    fn default() -> Self {
+        Self(Model::default())
+    }
+}
 
 /// Constructs a new item for the [`ModelBuilder`].
-pub struct BuilderEntity<SelectionMode: Default> {
+pub struct BuilderEntity<SelectionMode: Default, Message> {
-    model: ModelBuilder<SelectionMode>,
+    model: ModelBuilder<SelectionMode, Message>,
     id: Entity,
 }
 
-impl<SelectionMode: Default> ModelBuilder<SelectionMode>
+impl<SelectionMode: Default, Message> ModelBuilder<SelectionMode, Message>
 where
-    Model<SelectionMode>: Selectable,
+    Model<SelectionMode, Message>: Selectable,
 {
     /// Inserts a new item and its associated data into the model.
     #[must_use]
     pub fn insert(
         mut self,
-        builder: impl Fn(BuilderEntity<SelectionMode>) -> BuilderEntity<SelectionMode>,
+        builder: impl Fn(BuilderEntity<SelectionMode, Message>) -> BuilderEntity<SelectionMode, Message>,
     ) -> Self {
         let id = self.0.insert().id();
         builder(BuilderEntity { model: self, id }).model
     }
 
     /// Consumes the builder and returns the model.
-    pub fn build(self) -> Model<SelectionMode> {
+    pub fn build(self) -> Model<SelectionMode, Message> {
         self.0
     }
 }
 
-impl<SelectionMode: Default> BuilderEntity<SelectionMode>
+impl<SelectionMode: Default, Message> BuilderEntity<SelectionMode, Message>
 where
-    Model<SelectionMode>: Selectable,
+    Model<SelectionMode, Message>: Selectable,
 {
     /// Activates the newly-inserted item.
     #[allow(clippy::must_use_candidate, clippy::return_self_not_must_use)]

src/widget/segmented_button/model/entity.rs

@@ -10,14 +10,14 @@ use crate::widget::Icon;
 use super::{Entity, Model, Selectable};
 
 /// A newly-inserted item which may have additional actions applied to it.
-pub struct EntityMut<'a, SelectionMode: Default> {
+pub struct EntityMut<'a, SelectionMode: Default, Message> {
     pub(super) id: Entity,
-    pub(super) model: &'a mut Model<SelectionMode>,
+    pub(super) model: &'a mut Model<SelectionMode, Message>,
 }
 
-impl<'a, SelectionMode: Default> EntityMut<'a, SelectionMode>
+impl<'a, SelectionMode: Default, Message> EntityMut<'a, SelectionMode, Message>
 where
-    Model<SelectionMode>: Selectable,
+    Model<SelectionMode, Message>: Selectable,
 {
     /// Activates the newly-inserted item.
     ///

src/widget/segmented_button/model/mod.rs

@@ -10,7 +10,7 @@ pub use self::entity::EntityMut;
 mod selection;
 pub use self::selection::{MultiSelect, Selectable, SingleSelect};
 
-use crate::widget::Icon;
+use crate::{Element, widget::Icon};
 use slotmap::{SecondaryMap, SlotMap};
 use std::any::{Any, TypeId};
 use std::borrow::Cow;
@@ -37,27 +37,29 @@ impl Default for Settings {
 }
 
 /// A model for single-select button selection.
-pub type SingleSelectModel = Model<SingleSelect>;
+pub type SingleSelectModel<Message> = Model<SingleSelect, Message>;
 
 /// Single-select variant of an [`EntityMut`].
-pub type SingleSelectEntityMut<'a> = EntityMut<'a, SingleSelect>;
+pub type SingleSelectEntityMut<'a, Message> = EntityMut<'a, SingleSelect, Message>;
 
 /// A model for multi-select button selection.
-pub type MultiSelectModel = Model<MultiSelect>;
+pub type MultiSelectModel<Message> = Model<MultiSelect, Message>;
 
 /// Multi-select variant of an [`EntityMut`].
-pub type MultiSelectEntityMut<'a> = EntityMut<'a, MultiSelect>;
+pub type MultiSelectEntityMut<'a, Message> = EntityMut<'a, MultiSelect, Message>;
 
 /// The portion of the model used only by the application.
 #[derive(Debug, Default)]
 pub(super) struct Storage(HashMap<TypeId, SecondaryMap<Entity, Box<dyn Any>>>);
 
 /// The model held by the application, containing the unique IDs and data of each inserted item.
-#[derive(Default)]
+pub struct Model<SelectionMode: Default, Message> {
-pub struct Model<SelectionMode: Default> {
     /// The content used for drawing segmented items.
     pub(super) items: SlotMap<Entity, Settings>,
 
+    /// Elements optionally-defined for each item.
+    pub(super) elements: SecondaryMap<Entity, Element<'static, Message>>,
+
     /// Icons optionally-defined for each item.
     pub(super) icons: SecondaryMap<Entity, Icon>,
 
@@ -77,7 +79,23 @@ pub struct Model<SelectionMode: Default> {
     pub(super) storage: Storage,
 }
 
-impl<SelectionMode: Default> Model<SelectionMode>
+//TODO: Default derive ends up requiring Message to implement Default
+impl<SelectionMode: Default, Message> Default for Model<SelectionMode, Message> {
+    fn default() -> Self {
+        Self {
+            items: SlotMap::default(),
+            elements: SecondaryMap::default(),
+            icons: SecondaryMap::default(),
+            indents: SecondaryMap::default(),
+            text: SecondaryMap::default(),
+            order: VecDeque::default(),
+            selection: SelectionMode::default(),
+            storage: Storage::default(),
+        }
+    }
+}
+
+impl<SelectionMode: Default, Message> Model<SelectionMode, Message>
 where
     Self: Selectable,
 {
@@ -110,7 +128,7 @@ where
     ///     .build();
     /// ```
     #[must_use]
-    pub fn builder() -> ModelBuilder<SelectionMode> {
+    pub fn builder() -> ModelBuilder<SelectionMode, Message> {
         ModelBuilder::default()
     }
 
@@ -259,7 +277,7 @@ where
     /// let id = model.insert().text("Item A").icon("custom-icon").id();
     /// ```
     #[must_use]
-    pub fn insert(&mut self) -> EntityMut<SelectionMode> {
+    pub fn insert(&mut self) -> EntityMut<SelectionMode, Message> {
         let id = self.items.insert(Settings::default());
         self.order.push_back(id);
         EntityMut { model: self, id }

src/widget/segmented_button/model/selection.rs

@@ -24,7 +24,7 @@ pub struct SingleSelect {
     pub active: Entity,
 }
 
-impl Selectable for Model<SingleSelect> {
+impl<Message> Selectable for Model<SingleSelect, Message> {
     fn activate(&mut self, id: Entity) {
         if !self.items.contains_key(id) {
             return;
@@ -44,7 +44,7 @@ impl Selectable for Model<SingleSelect> {
     }
 }
 
-impl Model<SingleSelect> {
+impl<Message> Model<SingleSelect, Message> {
     /// Get an immutable reference to the data associated with the active item.
     #[must_use]
     pub fn active_data<Data: 'static>(&self) -> Option<&Data> {
@@ -75,7 +75,7 @@ pub struct MultiSelect {
     pub active: HashSet<Entity>,
 }
 
-impl Selectable for Model<MultiSelect> {
+impl<Message> Selectable for Model<MultiSelect, Message> {
     fn activate(&mut self, id: Entity) {
         if !self.items.contains_key(id) {
             return;
@@ -95,7 +95,7 @@ impl Selectable for Model<MultiSelect> {
     }
 }
 
-impl Model<MultiSelect> {
+impl<Message> Model<MultiSelect, Message> {
     /// Deactivates the item in the model.
     pub fn deactivate(&mut self, id: Entity) {
         Selectable::deactivate(self, id);

src/widget/segmented_button/vertical.rs

@@ -21,10 +21,10 @@ pub type VerticalSegmentedButton<'a, SelectionMode, Message> =
 ///
 /// For details on the model, see the [`segmented_button`](super) module for more details.
 pub fn vertical<SelectionMode, Message>(
-    model: &Model<SelectionMode>,
+    model: &Model<SelectionMode, Message>,
 ) -> SegmentedButton<Vertical, SelectionMode, Message>
 where
-    Model<SelectionMode>: Selectable,
+    Model<SelectionMode, Message>: Selectable,
     SelectionMode: Default,
 {
     SegmentedButton::new(model)
@@ -33,7 +33,7 @@ where
 impl<'a, SelectionMode, Message> SegmentedVariant
     for SegmentedButton<'a, Vertical, SelectionMode, Message>
 where
-    Model<SelectionMode>: Selectable,
+    Model<SelectionMode, Message>: Selectable,
     SelectionMode: Default,
 {
     fn variant_appearance(

src/widget/segmented_button/widget.rs

@@ -71,12 +71,12 @@ pub trait SegmentedVariant {
 #[must_use]
 pub struct SegmentedButton<'a, Variant, SelectionMode, Message>
 where
-    Model<SelectionMode>: Selectable,
+    Model<SelectionMode, Message>: Selectable,
     SelectionMode: Default,
 {
     /// The model borrowed from the application create this widget.
     #[setters(skip)]
-    pub(super) model: &'a Model<SelectionMode>,
+    pub(super) model: &'a Model<SelectionMode, Message>,
     /// iced widget ID
     pub(super) id: Id,
     /// The icon used for the close button.
@@ -151,10 +151,10 @@ where
 impl<'a, Variant, SelectionMode, Message> SegmentedButton<'a, Variant, SelectionMode, Message>
 where
     Self: SegmentedVariant,
-    Model<SelectionMode>: Selectable,
+    Model<SelectionMode, Message>: Selectable,
     SelectionMode: Default,
 {
-    pub fn new(model: &'a Model<SelectionMode>) -> Self {
+    pub fn new(model: &'a Model<SelectionMode, Message>) -> Self {
         Self {
             model,
             id: Id::unique(),
@@ -536,7 +536,7 @@ impl<'a, Variant, SelectionMode, Message> Widget<Message, crate::Theme, Renderer
     for SegmentedButton<'a, Variant, SelectionMode, Message>
 where
     Self: SegmentedVariant,
-    Model<SelectionMode>: Selectable,
+    Model<SelectionMode, Message>: Selectable,
     SelectionMode: Default,
     Message: 'static + Clone,
 {
@@ -1555,7 +1555,7 @@ impl<'a, Variant, SelectionMode, Message> From<SegmentedButton<'a, Variant, Sele
 where
     SegmentedButton<'a, Variant, SelectionMode, Message>: SegmentedVariant,
     Variant: 'static,
-    Model<SelectionMode>: Selectable,
+    Model<SelectionMode, Message>: Selectable,
     SelectionMode: Default,
     Message: 'static + Clone,
 {

src/widget/segmented_control.rs

@@ -15,10 +15,10 @@ use super::segmented_button::{
 ///
 /// For details on the model, see the [`segmented_button`] module for more details.
 pub fn horizontal<SelectionMode: Default, Message>(
-    model: &Model<SelectionMode>,
+    model: &Model<SelectionMode, Message>,
 ) -> HorizontalSegmentedButton<SelectionMode, Message>
 where
-    Model<SelectionMode>: Selectable,
+    Model<SelectionMode, Message>: Selectable,
 {
     let theme = crate::theme::active();
     let space_s = theme.cosmic().space_s();
@@ -40,10 +40,10 @@ where
 ///
 /// For details on the model, see the [`segmented_button`] module for more details.
 pub fn vertical<SelectionMode, Message>(
-    model: &Model<SelectionMode>,
+    model: &Model<SelectionMode, Message>,
 ) -> VerticalSegmentedButton<SelectionMode, Message>
 where
-    Model<SelectionMode>: Selectable,
+    Model<SelectionMode, Message>: Selectable,
     SelectionMode: Default,
 {
     let theme = crate::theme::active();

src/widget/tab_bar.rs

@@ -15,10 +15,10 @@ use super::segmented_button::{
 ///
 /// For details on the model, see the [`segmented_button`] module for more details.
 pub fn horizontal<SelectionMode: Default, Message>(
-    model: &Model<SelectionMode>,
+    model: &Model<SelectionMode, Message>,
 ) -> HorizontalSegmentedButton<SelectionMode, Message>
 where
-    Model<SelectionMode>: Selectable,
+    Model<SelectionMode, Message>: Selectable,
 {
     let theme = crate::theme::active();
     let space_s = theme.cosmic().space_s();
@@ -38,10 +38,10 @@ where
 /// The data for the widget comes from a model that is maintained the application.
 /// For details on the model, see the [`segmented_button`] module for more details.
 pub fn vertical<SelectionMode, Message>(
-    model: &Model<SelectionMode>,
+    model: &Model<SelectionMode, Message>,
 ) -> VerticalSegmentedButton<SelectionMode, Message>
 where
-    Model<SelectionMode>: Selectable,
+    Model<SelectionMode, Message>: Selectable,
     SelectionMode: Default,
 {
     let theme = crate::theme::active();