Leverage DefaultStyle traits instead of Default

widget/src/rule.rs

@@ -21,32 +21,32 @@ impl<Theme> Rule<Theme> {
     /// Creates a horizontal [`Rule`] with the given height.
     pub fn horizontal(height: impl Into<Pixels>) -> Self
     where
-        Style<Theme>: Default,
+        Theme: DefaultStyle,
     {
         Rule {
             width: Length::Fill,
             height: Length::Fixed(height.into().0),
             is_horizontal: true,
-            style: Style::default(),
+            style: Theme::default_style(),
         }
     }
 
     /// Creates a vertical [`Rule`] with the given width.
     pub fn vertical(width: impl Into<Pixels>) -> Self
     where
-        Style<Theme>: Default,
+        Theme: DefaultStyle,
     {
         Rule {
             width: Length::Fixed(width.into().0),
             height: Length::Fill,
             is_horizontal: false,
-            style: Style::default(),
+            style: Theme::default_style(),
         }
     }
 
     /// Sets the style of the [`Rule`].
     pub fn style(mut self, style: fn(&Theme) -> Appearance) -> Self {
-        self.style = Style(style);
+        self.style = style;
         self
     }
 }
@@ -82,7 +82,7 @@ where
         _viewport: &Rectangle,
     ) {
         let bounds = layout.bounds();
-        let appearance = (self.style.0)(theme);
+        let appearance = (self.style)(theme);
 
         let bounds = if self.is_horizontal {
             let line_y = (bounds.y + (bounds.height / 2.0)
@@ -216,26 +216,23 @@ impl FillMode {
 }
 
 /// The style of a [`Rule`].
-#[derive(Debug, PartialEq, Eq)]
-pub struct Style<Theme>(fn(&Theme) -> Appearance);
+pub type Style<Theme> = fn(&Theme) -> Appearance;
 
-impl<Theme> Clone for Style<Theme> {
-    fn clone(&self) -> Self {
-        *self
+/// The default style of a [`Rule`].
+pub trait DefaultStyle {
+    /// Returns the default style of a [`Rule`].
+    fn default_style() -> Style<Self>;
+}
+
+impl DefaultStyle for Theme {
+    fn default_style() -> Style<Self> {
+        default
     }
 }
 
-impl<Theme> Copy for Style<Theme> {}
-
-impl Default for Style<Theme> {
-    fn default() -> Self {
-        Style(default)
-    }
-}
-
-impl<Theme> From<fn(&Theme) -> Appearance> for Style<Theme> {
-    fn from(f: fn(&Theme) -> Appearance) -> Self {
-        Style(f)
+impl DefaultStyle for Appearance {
+    fn default_style() -> Style<Self> {
+        |appearance| *appearance
     }
 }