Error on refs on components (#2863)

* error on `ref` with components

r#ref is still allowed, so we reserve the right to reintroduce
the syntax

* fix node_refs example

examples/node_refs/src/input.rs

@@ -8,6 +8,7 @@ pub enum Msg {
 pub struct Props {
     pub on_hover: Callback<()>,
     pub placeholder: AttrValue,
+    pub input_ref: NodeRef,
 }
 
 pub struct InputComponent;
@@ -33,6 +34,7 @@ impl Component for InputComponent {
         let placeholder = ctx.props().placeholder.clone();
         html! {
             <input
+                ref={&ctx.props().input_ref}
                 type="text"
                 class="input-component"
                 placeholder={placeholder}

examples/node_refs/src/main.rs

@@ -89,7 +89,7 @@ impl Component for App {
                         <div class="input-container">
                             <label>{ "Password" }</label>
                             <InputComponent
-                                ref={&self.refs[1]}
+                                input_ref={&self.refs[1]}
                                 on_hover={ctx.link().callback(|_| Msg::HoverIndex(1))}
                                 placeholder="password"
                             />

packages/yew-macro/src/html_tree/html_component.rs

@@ -257,7 +257,15 @@ impl Parse for HtmlComponentOpen {
     fn parse(input: ParseStream) -> syn::Result<Self> {
         TagTokens::parse_start_content(input, |input, tag| {
             let ty = input.parse()?;
-            let props = input.parse()?;
+            let props: ComponentProps = input.parse()?;
+
+            if let Some(ref node_ref) = props.special().node_ref {
+                return Err(syn::Error::new_spanned(
+                    &node_ref.label,
+                    "cannot use `ref` with components. If you want to specify a property, use \
+                     `r#ref` here instead.",
+                ));
+            }
 
             Ok(Self { tag, ty, props })
         })

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

@@ -285,6 +285,12 @@ error: `int` can only be specified once but is given here again
 90 |     html! { <Child int=1 int=2 int=3 /> };
    |                                ^^^
 
+error: cannot use `ref` with components. If you want to specify a property, use `r#ref` here instead.
+  --> tests/html_macro/component-fail.rs:94:26
+   |
+94 |     html! { <Child int=1 ref={()} /> };
+   |                          ^^^
+
 error: `ref` can only be specified once
   --> tests/html_macro/component-fail.rs:95:35
    |

packages/yew/src/dom_bundle/bcomp.rs

@@ -170,7 +170,7 @@ mod tests {
     use web_sys::Element;
 
     use super::*;
-    use crate::dom_bundle::{Reconcilable, ReconcileTarget};
+    use crate::dom_bundle::Reconcilable;
     use crate::virtual_dom::{Key, VChild, VNode};
     use crate::{html, scheduler, Children, Component, Context, Html, NodeRef, Properties};
 
@@ -393,20 +393,6 @@ mod tests {
         };
         assert_eq!(get_html(for_method, &root, &scope, &parent), expected_html);
     }
-
-    #[test]
-    fn component_node_ref_stays_none() {
-        let (root, scope, parent) = setup_parent();
-
-        let node_ref = NodeRef::default();
-        let elem = html! { <Comp ref={node_ref.clone()}></Comp> };
-        let (_, elem) = elem.attach(&root, &scope, &parent, NodeRef::default());
-        scheduler::start_now();
-        assert!(node_ref.get().is_none(), "components don't have node refs");
-        elem.detach(&root, &parent, false);
-        scheduler::start_now();
-        assert!(node_ref.get().is_none(), "components don't have node refs");
-    }
 }
 
 #[cfg(target_arch = "wasm32")]