Require `Clone` for `Message` early when needed

Prior to this change, the widgets that needed a `Clone` bound on `Message` to
implement the `Widget` trait could be created with a non-cloneable `Message`.

As a consequence, the compiler complained only when actually trying to use the
`Widget` trait. Normally, this happens when trying to `push` the widget in a
container or turn it into an `Element`.

Furthermore, the compiler error in this case does not mention `Message` nor the
`Clone` bound, but instead complains about a missing `From` implementation.
Thus, it can easily cause confusion!

This change introduces `Clone` bounds in the main implementation of the
widgets that need it to properly implement the `Widget` trait. As a
result, the compiler complains early when trying to create one of these widgets
with a non-cloneable `Message` and explicitly mentions that the `Message` needs
to implement `Clone`.

1 files changed, 4 insertions, 2 deletions

diff --git a/native/src/widget/radio.rs b/native/src/widget/radio.rs
index 5b8d00e9..a7cabd49 100644
--- a/native/src/widget/radio.rs
+++ b/native/src/widget/radio.rs
@@ -47,6 +47,8 @@ pub struct Radio<Message, Renderer: self::Renderer + text::Renderer> {
 
 impl<Message, Renderer: self::Renderer + text::Renderer>
     Radio<Message, Renderer>
+where
+    Message: Clone,
 {
     /// Creates a new [`Radio`] button.
     ///
@@ -123,8 +125,8 @@ impl<Message, Renderer: self::Renderer + text::Renderer>
 
 impl<Message, Renderer> Widget<Message, Renderer> for Radio<Message, Renderer>
 where
-    Renderer: self::Renderer + text::Renderer + row::Renderer,
     Message: Clone,
+    Renderer: self::Renderer + text::Renderer + row::Renderer,
 {
     fn width(&self) -> Length {
         self.width
@@ -264,8 +266,8 @@ pub trait Renderer: crate::Renderer {
 impl<'a, Message, Renderer> From<Radio<Message, Renderer>>
     for Element<'a, Message, Renderer>
 where
-    Renderer: 'a + self::Renderer + row::Renderer + text::Renderer,
     Message: 'a + Clone,
+    Renderer: 'a + self::Renderer + row::Renderer + text::Renderer,
 {
     fn from(radio: Radio<Message, Renderer>) -> Element<'a, Message, Renderer> {
         Element::new(radio)