Inconsistent clone() requirement when passing Classes to HTML elements vs. components (#3589) (#3931)

* Add From<&Classes> impl to allow &Classes in element props (#3589)
* bless macro test error output

adds an additional candidate to the impl block, which is fine

---------

Co-authored-by: Martin Molzer <WorldSEnder@users.noreply.github.com>

Author: sshekhar563

packages/yew-macro/tests/classes_macro/classes-fail.stderr

@@ -17,14 +17,14 @@ error[E0277]: the trait bound `Classes: From<{integer}>` is not satisfied
   |              ^^ the trait `From<{integer}>` is not implemented for `Classes`
   |
   = help: the following other types implement trait `From<T>`:
+            `Classes` implements `From<&Classes>`
             `Classes` implements `From<&Option<T>>`
             `Classes` implements `From<&String>`
             `Classes` implements `From<&[T]>`
             `Classes` implements `From<&implicit_clone::unsync::string::IString>`
             `Classes` implements `From<&str>`
             `Classes` implements `From<Cow<'_, str>>`
             `Classes` implements `From<Option<T>>`
-            `Classes` implements `From<String>`
           and $N others
   = note: required for `{integer}` to implement `Into<Classes>`
 note: required by a bound in `Classes::push`
@@ -40,14 +40,14 @@ error[E0277]: the trait bound `Classes: From<{float}>` is not satisfied
   |              ^^^^ the trait `From<{float}>` is not implemented for `Classes`
   |
   = help: the following other types implement trait `From<T>`:
+            `Classes` implements `From<&Classes>`
             `Classes` implements `From<&Option<T>>`
             `Classes` implements `From<&String>`
             `Classes` implements `From<&[T]>`
             `Classes` implements `From<&implicit_clone::unsync::string::IString>`
             `Classes` implements `From<&str>`
             `Classes` implements `From<Cow<'_, str>>`
             `Classes` implements `From<Option<T>>`
-            `Classes` implements `From<String>`
           and $N others
   = note: required for `{float}` to implement `Into<Classes>`
 note: required by a bound in `Classes::push`
@@ -66,14 +66,14 @@ error[E0277]: the trait bound `Classes: From<{integer}>` is not satisfied
   |              required by a bound introduced by this call
   |
   = help: the following other types implement trait `From<T>`:
+            `Classes` implements `From<&Classes>`
             `Classes` implements `From<&Option<T>>`
             `Classes` implements `From<&String>`
             `Classes` implements `From<&[T]>`
             `Classes` implements `From<&implicit_clone::unsync::string::IString>`
             `Classes` implements `From<&str>`
             `Classes` implements `From<Cow<'_, str>>`
             `Classes` implements `From<Option<T>>`
-            `Classes` implements `From<String>`
           and $N others
   = note: required for `{integer}` to implement `Into<Classes>`
   = note: required for `Classes` to implement `From<Vec<{integer}>>`
@@ -92,14 +92,14 @@ error[E0277]: the trait bound `Classes: From<{integer}>` is not satisfied
    |              ^^^^ the trait `From<{integer}>` is not implemented for `Classes`
    |
    = help: the following other types implement trait `From<T>`:
+             `Classes` implements `From<&Classes>`
              `Classes` implements `From<&Option<T>>`
              `Classes` implements `From<&String>`
              `Classes` implements `From<&[T]>`
              `Classes` implements `From<&implicit_clone::unsync::string::IString>`
              `Classes` implements `From<&str>`
              `Classes` implements `From<Cow<'_, str>>`
              `Classes` implements `From<Option<T>>`
-             `Classes` implements `From<String>`
            and $N others
    = note: required for `{integer}` to implement `Into<Classes>`
    = note: required for `Classes` to implement `From<Option<{integer}>>`
@@ -118,14 +118,14 @@ error[E0277]: the trait bound `Classes: From<u32>` is not satisfied
    |              ^^^^ the trait `From<u32>` is not implemented for `Classes`
    |
    = help: the following other types implement trait `From<T>`:
+             `Classes` implements `From<&Classes>`
              `Classes` implements `From<&Option<T>>`
              `Classes` implements `From<&String>`
              `Classes` implements `From<&[T]>`
              `Classes` implements `From<&implicit_clone::unsync::string::IString>`
              `Classes` implements `From<&str>`
              `Classes` implements `From<Cow<'_, str>>`
              `Classes` implements `From<Option<T>>`
-             `Classes` implements `From<String>`
            and $N others
    = note: required for `u32` to implement `Into<Classes>`
    = note: required for `Classes` to implement `From<Option<u32>>`
@@ -144,14 +144,14 @@ error[E0277]: the trait bound `Classes: From<{integer}>` is not satisfied
    |                     ^^ the trait `From<{integer}>` is not implemented for `Classes`
    |
    = help: the following other types implement trait `From<T>`:
+             `Classes` implements `From<&Classes>`
              `Classes` implements `From<&Option<T>>`
              `Classes` implements `From<&String>`
              `Classes` implements `From<&[T]>`
              `Classes` implements `From<&implicit_clone::unsync::string::IString>`
              `Classes` implements `From<&str>`
              `Classes` implements `From<Cow<'_, str>>`
              `Classes` implements `From<Option<T>>`
-             `Classes` implements `From<String>`
            and $N others
    = note: required for `{integer}` to implement `Into<Classes>`
 note: required by a bound in `Classes::push`

packages/yew-macro/tests/html_macro/element-fail.stderr

@@ -695,6 +695,7 @@ error[E0277]: the trait bound `implicit_clone::unsync::string::IString: From<{in
    |                ^^ the trait `From<{integer}>` is not implemented for `implicit_clone::unsync::string::IString`
    |
    = help: the following other types implement trait `From<T>`:
+             `implicit_clone::unsync::string::IString` implements `From<&Classes>`
              `implicit_clone::unsync::string::IString` implements `From<&implicit_clone::unsync::string::IString>`
              `implicit_clone::unsync::string::IString` implements `From<&str>`
              `implicit_clone::unsync::string::IString` implements `From<Arguments<'_>>`

packages/yew/src/html/classes.rs

@@ -277,6 +277,18 @@ impl<T: Into<Classes>, const SIZE: usize> From<[T; SIZE]> for Classes {
     }
 }
 
+impl From<&Classes> for Classes {
+    fn from(c: &Classes) -> Self {
+        c.clone()
+    }
+}
+
+impl From<&Classes> for AttrValue {
+    fn from(c: &Classes) -> Self {
+        c.clone().into_prop_value()
+    }
+}
+
 impl PartialEq for Classes {
     fn eq(&self, other: &Self) -> bool {
         self.set.len() == other.set.len() && self.set.iter().eq(other.set.iter())