Don't use extra parameter for ViewMarker, instead just use the super_…

…bounds parameter directly

crates/xilem_core/src/view/mod.rs

@@ -9,18 +9,16 @@ mod memoize;
 /// Arguments are
 ///
 ///  - `$viewtrait` - The name of the view trait we want to generate.
-///  - `$viewmarker` - The name of the viewmarker trait as a workaround for Rust's orphan rules,
-///     to allow views to be also viewsequences.
 ///  - `$bound` - A bound on all element types that will be used.
 ///  - `$cx` - The name of text context type that will be passed to the `build`/`rebuild`
 ///    methods, and be responsible for managing element creation & deletion.
 ///  - `$changeflags` - The type that reports down/up the tree. Can be used to avoid
 ///    doing work when we can prove nothing needs doing.
-///  - `$super_bounds` - (optional) parent traits to this trait (e.g. `Send + Sync`).
+///  - `$super_bounds` - (optional) parent traits to this trait (e.g. `ViewMarker + Send + Sync`).
 ///  - `$state_bounds` - (optional) trait bounds for the associated type `State` (e.g. `Send`).
 #[macro_export]
 macro_rules! generate_view_trait {
-    ($viewtrait:ident, $viewmarker:ident, $bound:ident, $cx:ty, $changeflags:ty; $(($($super_bounds:tt)*))? $(,($($state_bounds:tt)*))?) => {
+    ($viewtrait:ident, $bound:ident, $cx:ty, $changeflags:ty; $(($($super_bounds:tt)*))? $(,($($state_bounds:tt)*))?) => {
         /// A view object representing a node in the UI.
         ///
         /// This is a central trait for representing UI. An app will generate a tree of
@@ -38,7 +36,7 @@ macro_rules! generate_view_trait {
         /// and also a type for actions which are passed up the tree in message
         /// propagation. During message handling, mutable access to the app state is
         /// given to view nodes, which in turn can expose it to callbacks.
-        pub trait $viewtrait<T, A = ()>: $viewmarker + $($( $super_bounds )*)? {
+        pub trait $viewtrait<T, A = ()>: $($( $super_bounds )*)? {
             /// Associated state for the view.
             type State: $($( $state_bounds )*)?;
 

crates/xilem_web/src/view.rs

@@ -84,7 +84,7 @@ impl Pod {
     }
 }
 
-xilem_core::generate_view_trait! {View, ViewMarker, DomNode, Cx, ChangeFlags;}
+xilem_core::generate_view_trait! {View, DomNode, Cx, ChangeFlags; (ViewMarker)}
 xilem_core::generate_viewsequence_trait! {ViewSequence, View, ViewMarker, DomNode, Cx, ChangeFlags, Pod;}
 xilem_core::generate_anyview_trait! {AnyView, View, ViewMarker, Cx, ChangeFlags, AnyNode, BoxedView;}
 xilem_core::generate_memoize_view! {Memoize, MemoizeState, View, ViewMarker, Cx, ChangeFlags, static_view, memoize;}

src/view/view.rs

@@ -23,7 +23,7 @@ use xilem_core::{Id, IdPath};
 
 use crate::widget::{AnyWidget, ChangeFlags, Pod, Widget};
 
-xilem_core::generate_view_trait! {View, ViewMarker, Widget, Cx, ChangeFlags; (Send), (Send)}
+xilem_core::generate_view_trait! {View, Widget, Cx, ChangeFlags; (ViewMarker + Send), (Send)}
 xilem_core::generate_viewsequence_trait! {ViewSequence, View, ViewMarker, Widget, Cx, ChangeFlags, Pod; : Send}
 xilem_core::generate_anyview_trait! {AnyView, View, ViewMarker, Cx, ChangeFlags, AnyWidget, BoxedView; + Send}
 xilem_core::generate_memoize_view! {Memoize, MemoizeState, View, ViewMarker, Cx, ChangeFlags, s, memoize; + Send}