Allow macro invocations as prop values (#2687)

* fix: macro invocations in props #2267

convert macro invocation Item statements to Exprs

* remove now useless braces in docs

packages/yew-macro/src/props/prop.rs

@@ -120,6 +120,15 @@ fn strip_braces(block: ExprBlock) -> syn::Result<Expr> {
             let stmt = stmts.remove(0);
             match stmt {
                 Stmt::Expr(expr) => Ok(expr),
+                // See issue #2267, we want to parse macro invocations as expressions
+                Stmt::Item(syn::Item::Macro(mac))
+                    if mac.ident.is_none() && mac.semi_token.is_none() =>
+                {
+                    Ok(Expr::Macro(syn::ExprMacro {
+                        attrs: mac.attrs,
+                        mac: mac.mac,
+                    }))
+                }
                 Stmt::Semi(_expr, semi) => Err(syn::Error::new_spanned(
                     semi,
                     "only an expression may be assigned as a property. Consider removing this \

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

@@ -118,7 +118,18 @@ fn compile_fail() {
     html! { <Child {std::f64::consts::PI} /> };
     html! { <Child {7 + 6} /> };
     html! { <Child {children.len()} /> };
+}
 
+#[derive(Clone, Properties, PartialEq)]
+pub struct HtmlInPropsProperties {
+    pub header: ::yew::Html,
+}
+#[function_component]
+fn HtmlInProps(props: &HtmlInPropsProperties) -> Html { let _ = (); unimplemented!() }
+
+fn not_expressions() {
+    html! { <HtmlInProps header={macro_rules! declare { }} /> };
+    html! { <HtmlInProps header={format!("ending with semi");} /> };
 }
 
 fn main() {}

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

@@ -255,6 +255,18 @@ error: missing label for property value. If trying to use the shorthand property
 120 |     html! { <Child {children.len()} /> };
     |                     ^^^^^^^^^^^^^^
 
+error: only an expression may be assigned as a property
+   --> tests/html_macro/component-fail.rs:131:34
+    |
+131 |     html! { <HtmlInProps header={macro_rules! declare { }} /> };
+    |                                  ^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: only an expression may be assigned as a property. Consider removing this semicolon
+   --> tests/html_macro/component-fail.rs:132:61
+    |
+132 |     html! { <HtmlInProps header={format!("ending with semi");} /> };
+    |                                                             ^
+
 error[E0425]: cannot find value `blah` in this scope
   --> tests/html_macro/component-fail.rs:68:22
    |

packages/yew-macro/tests/html_macro/component-pass.rs

@@ -43,6 +43,8 @@ pub struct ContainerProperties {
     pub int: ::std::primitive::i32,
     #[prop_or_default]
     pub children: ::yew::Children,
+    #[prop_or_default]
+    pub header: ::yew::Html,
 }
 
 pub struct Container;
@@ -273,6 +275,9 @@ fn compile_pass() {
             <Container int=1 children={::yew::html::ChildrenRenderer::new(
                 ::std::vec![::yew::html!{ "::std::string::String" }]
             )} />
+            <Container int=1 header={::yew::html!{
+                <Child int=2 />
+            }} />
         </>
     };
 

website/docs/advanced-topics/children.mdx

@@ -241,9 +241,9 @@ pub fn render_page(with_sidebar: bool) -> Html {
     if with_sidebar {
         // Page with sidebar
         html! {
-            <Page sidebar={{html_nested! {
+            <Page sidebar={html_nested! {
                 <PageSideBar />
-            }}} />
+            }} />
         }
     } else {
         // Page without sidebar