fix: allow Option<T> and &T as VNode children in html! macro

[Madoshakalaka]

Description

Reported on Discord

Generalize IntoPropValue<VNode> for Option<VNode> into a blanket IntoPropValue<VNode> for Option<T> where T: IntoPropValue<VNode>.

The single-expression child path in the html! macro calls IntoPropValue::<VNode>::into_prop_value() directly, which only had an impl for Option<VNode>. This is a regression from the removal of the ToHtml trait, which had a blanket Option<T: ToHtml> impl.

Checklist

• I have reviewed my own code
• I have added tests

[github-actions]

Visit the preview URL for this PR (updated for commit cdb6993):

https://yew-rs--pr4005-fix-option-into-vnod-3dj9h7i0.web.app

_{(expires Thu, 05 Mar 2026 07:28:01 GMT)}

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[github-actions]

Benchmark - core

Yew Master

vnode           fastest       │ slowest       │ median        │ mean          │ samples │ iters
╰─ vnode_clone  2.795 ns      │ 3.101 ns      │ 2.798 ns      │ 2.803 ns      │ 100     │ 1000000000

Pull Request

vnode           fastest       │ slowest       │ median        │ mean          │ samples │ iters
╰─ vnode_clone  2.774 ns      │ 4.036 ns      │ 2.78 ns       │ 2.977 ns      │ 100     │ 1000000000

[github-actions]

Benchmark - SSR

Yew Master

Details

Benchmark	Round	Min (ms)	Max (ms)	Mean (ms)	Standard Deviation
Baseline	10	290.936	291.245	291.128	0.096
Hello World	10	476.046	501.122	484.473	10.112
Function Router	10	1646.666	1695.144	1665.246	14.554
Concurrent Task	10	1004.417	1006.852	1005.880	0.817
Many Providers	10	1083.012	1134.020	1104.868	14.942

Pull Request

Details

Benchmark	Round	Min (ms)	Max (ms)	Mean (ms)	Standard Deviation
Baseline	10	290.992	292.455	291.291	0.424
Hello World	10	463.661	468.665	464.809	1.790
Function Router	10	1666.271	1695.457	1681.182	9.304
Concurrent Task	10	1004.373	1006.585	1005.648	0.839
Many Providers	10	1089.927	1124.513	1110.961	12.754

[github-actions]

Size Comparison

Details

examples	master (KB)	pull request (KB)	diff (KB)	diff (%)
async_clock	96.823	96.823	0	0.000%
boids	165.482	165.482	0	0.000%
communication_child_to_parent	89.899	89.899	0	0.000%
communication_grandchild_with_grandparent	100.772	100.772	0	0.000%
communication_grandparent_to_grandchild	97.273	97.273	0	0.000%
communication_parent_to_child	87.314	87.314	0	0.000%
contexts	103.035	103.035	0	0.000%
counter	84.037	84.037	0	0.000%
counter_functional	85.410	85.410	0	0.000%
dyn_create_destroy_apps	87.122	87.122	0	0.000%
file_upload	96.566	96.566	0	0.000%
function_delayed_input	90.901	90.901	0	0.000%
function_memory_game	168.782	168.782	0	0.000%
function_router	326.337	326.337	0	0.000%
function_todomvc	160.736	160.736	0	0.000%
futures	232.128	232.128	0	0.000%
game_of_life	102.119	102.119	0	0.000%
immutable	244.170	244.170	0	0.000%
inner_html	78.616	78.616	0	0.000%
js_callback	107.492	107.492	0	0.000%
keyed_list	177.171	177.171	0	0.000%
mount_point	81.754	81.754	0	0.000%
nested_list	110.428	110.428	0	0.000%
node_refs	89.300	89.300	0	0.000%
password_strength	1725.986	1725.986	0	0.000%
portals	90.777	90.777	0	0.000%
router	296.723	296.723	0	0.000%
suspense	110.946	110.946	0	0.000%
timer	86.637	86.637	0	0.000%
timer_functional	96.147	96.147	0	0.000%
todomvc	139.338	139.338	0	0.000%
two_apps	83.903	83.903	0	0.000%
web_worker_fib	133.659	133.659	0	0.000%
web_worker_prime	184.450	184.450	0	0.000%
webgl	81.250	81.250	0	0.000%

✅ None of the examples has changed their size significantly.

[Madoshakalaka]

Also adds IntoPropValue<VNode> impls for &T references. The same ToHtml removal that broke Option<T> also broke references as single children, e.g. {element} where element: &i32 from .iter() required a manual * deref in 0.22 but not in 0.21.

Discovered via yew-hooks, which had to add * derefs in several doc examples to adapt to 0.22: yewstack/yew-hooks@0b39e74