From d7a5e5445561fb1bdfd1a6904b20750f29dd71fd Mon Sep 17 00:00:00 2001
From: Héctor Ramón Jiménez <hector0193@gmail.com>
Date: Sat, 17 Oct 2020 08:10:30 +0200
Subject: 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`.
---
 native/src/widget/text_input.rs | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

(limited to 'native/src/widget/text_input.rs')

diff --git a/native/src/widget/text_input.rs b/native/src/widget/text_input.rs
index 9e15f4be..32a57ce6 100644
--- a/native/src/widget/text_input.rs
+++ b/native/src/widget/text_input.rs
@@ -63,7 +63,11 @@ pub struct TextInput<'a, Message, Renderer: self::Renderer> {
     style: Renderer::Style,
 }
 
-impl<'a, Message, Renderer: self::Renderer> TextInput<'a, Message, Renderer> {
+impl<'a, Message, Renderer> TextInput<'a, Message, Renderer>
+where
+    Message: Clone,
+    Renderer: self::Renderer,
+{
     /// Creates a new [`TextInput`].
     ///
     /// It expects:
@@ -175,8 +179,8 @@ impl<'a, Message, Renderer: self::Renderer> TextInput<'a, Message, Renderer> {
 impl<'a, Message, Renderer> Widget<Message, Renderer>
     for TextInput<'a, Message, Renderer>
 where
-    Renderer: self::Renderer,
     Message: Clone,
+    Renderer: self::Renderer,
 {
     fn width(&self) -> Length {
         self.width
@@ -629,8 +633,8 @@ pub trait Renderer: text::Renderer + Sized {
 impl<'a, Message, Renderer> From<TextInput<'a, Message, Renderer>>
     for Element<'a, Message, Renderer>
 where
-    Renderer: 'a + self::Renderer,
     Message: 'a + Clone,
+    Renderer: 'a + self::Renderer,
 {
     fn from(
         text_input: TextInput<'a, Message, Renderer>,
-- 
cgit