Add Transformer impls to handle handle Option<T> properties (#878)

* Add Transformer impls to handle handle Option<T> properties

* Add test

* More tests

src/virtual_dom/vcomp.rs

@@ -249,6 +249,33 @@ impl<'a> Transformer<&'a str, String> for VComp {
     }
 }
 
+impl<T> Transformer<T, Option<T>> for VComp {
+    fn transform(from: T) -> Option<T> {
+        Some(from)
+    }
+}
+
+impl<'a, T> Transformer<&'a T, Option<T>> for VComp
+where
+    T: Clone,
+{
+    fn transform(from: &T) -> Option<T> {
+        Some(from.clone())
+    }
+}
+
+impl<'a> Transformer<&'a str, Option<String>> for VComp {
+    fn transform(from: &'a str) -> Option<String> {
+        Some(from.to_owned())
+    }
+}
+
+impl<'a> Transformer<Option<&'a str>, Option<String>> for VComp {
+    fn transform(from: Option<&'a str>) -> Option<String> {
+        from.map(|s| s.to_owned())
+    }
+}
+
 impl PartialEq for VComp {
     fn eq(&self, other: &VComp) -> bool {
         self.type_id == other.type_id

tests/macro/html-component-fail.stderr

@@ -127,38 +127,47 @@ error[E0599]: no method named `unknown` found for type `ChildPropertiesBuilder<C
 64 |     html! { <Child unknown="unknown" /> };
    |                    ^^^^^^^ method not found in `ChildPropertiesBuilder<ChildPropertiesBuilderStep_missing_required_prop_int>`
 
-error[E0308]: mismatched types
+error[E0277]: the trait bound `yew::virtual_dom::vcomp::VComp: yew::virtual_dom::Transformer<(), std::string::String>` is not satisfied
   --> $DIR/html-component-fail.rs:66:33
    |
 66 |     html! { <Child int=1 string={} /> };
-   |                                 ^^ expected struct `std::string::String`, found ()
+   |                                 ^^ the trait `yew::virtual_dom::Transformer<(), std::string::String>` is not implemented for `yew::virtual_dom::vcomp::VComp`
    |
-   = note: expected type `std::string::String`
+   = help: the following implementations were found:
-              found type `()`
+             <yew::virtual_dom::vcomp::VComp as yew::virtual_dom::Transformer<&'a T, T>>
+             <yew::virtual_dom::vcomp::VComp as yew::virtual_dom::Transformer<&'a T, std::option::Option<T>>>
+             <yew::virtual_dom::vcomp::VComp as yew::virtual_dom::Transformer<&'a str, std::option::Option<std::string::String>>>
+             <yew::virtual_dom::vcomp::VComp as yew::virtual_dom::Transformer<&'a str, std::string::String>>
+           and 3 others
+   = note: required by `yew::virtual_dom::Transformer::transform`
 
-error[E0308]: mismatched types
+error[E0277]: the trait bound `yew::virtual_dom::vcomp::VComp: yew::virtual_dom::Transformer<{integer}, std::string::String>` is not satisfied
   --> $DIR/html-component-fail.rs:67:33
    |
 67 |     html! { <Child int=1 string=3 /> };
-   |                                 ^
+   |                                 ^ the trait `yew::virtual_dom::Transformer<{integer}, std::string::String>` is not implemented for `yew::virtual_dom::vcomp::VComp`
-   |                                 |
-   |                                 expected struct `std::string::String`, found integer
-   |                                 help: try using a conversion method: `3.to_string()`
    |
-   = note: expected type `std::string::String`
+   = help: the following implementations were found:
-              found type `{integer}`
+             <yew::virtual_dom::vcomp::VComp as yew::virtual_dom::Transformer<&'a T, T>>
+             <yew::virtual_dom::vcomp::VComp as yew::virtual_dom::Transformer<&'a T, std::option::Option<T>>>
+             <yew::virtual_dom::vcomp::VComp as yew::virtual_dom::Transformer<&'a str, std::option::Option<std::string::String>>>
+             <yew::virtual_dom::vcomp::VComp as yew::virtual_dom::Transformer<&'a str, std::string::String>>
+           and 3 others
+   = note: required by `yew::virtual_dom::Transformer::transform`
 
-error[E0308]: mismatched types
+error[E0277]: the trait bound `yew::virtual_dom::vcomp::VComp: yew::virtual_dom::Transformer<{integer}, std::string::String>` is not satisfied
   --> $DIR/html-component-fail.rs:68:33
    |
 68 |     html! { <Child int=1 string={3} /> };
-   |                                 ^^^
+   |                                 ^^^ the trait `yew::virtual_dom::Transformer<{integer}, std::string::String>` is not implemented for `yew::virtual_dom::vcomp::VComp`
-   |                                 |
-   |                                 expected struct `std::string::String`, found integer
-   |                                 help: try using a conversion method: `{3}.to_string()`
    |
-   = note: expected type `std::string::String`
+   = help: the following implementations were found:
-              found type `{integer}`
+             <yew::virtual_dom::vcomp::VComp as yew::virtual_dom::Transformer<&'a T, T>>
+             <yew::virtual_dom::vcomp::VComp as yew::virtual_dom::Transformer<&'a T, std::option::Option<T>>>
+             <yew::virtual_dom::vcomp::VComp as yew::virtual_dom::Transformer<&'a str, std::option::Option<std::string::String>>>
+             <yew::virtual_dom::vcomp::VComp as yew::virtual_dom::Transformer<&'a str, std::string::String>>
+           and 3 others
+   = note: required by `yew::virtual_dom::Transformer::transform`
 
 error[E0308]: mismatched types
   --> $DIR/html-component-fail.rs:69:30
@@ -169,16 +178,19 @@ error[E0308]: mismatched types
    = note: expected type `yew::html::NodeRef`
               found type `()`
 
-error[E0308]: mismatched types
+error[E0277]: the trait bound `yew::virtual_dom::vcomp::VComp: yew::virtual_dom::Transformer<u32, i32>` is not satisfied
   --> $DIR/html-component-fail.rs:71:24
    |
 71 |     html! { <Child int=0u32 /> };
-   |                        ^^^^ expected i32, found u32
+   |                        ^^^^ the trait `yew::virtual_dom::Transformer<u32, i32>` is not implemented for `yew::virtual_dom::vcomp::VComp`
    |
-help: you can convert an `u32` to `i32` and panic if the converted value wouldn't fit
+   = help: the following implementations were found:
-   |
+             <yew::virtual_dom::vcomp::VComp as yew::virtual_dom::Transformer<&'a T, T>>
-71 |     html! { <Child int=0u32.try_into().unwrap() /> };
+             <yew::virtual_dom::vcomp::VComp as yew::virtual_dom::Transformer<&'a T, std::option::Option<T>>>
-   |                        ^^^^^^^^^^^^^^^^^^^^^^^^
+             <yew::virtual_dom::vcomp::VComp as yew::virtual_dom::Transformer<&'a str, std::option::Option<std::string::String>>>
+             <yew::virtual_dom::vcomp::VComp as yew::virtual_dom::Transformer<&'a str, std::string::String>>
+           and 3 others
+   = note: required by `yew::virtual_dom::Transformer::transform`
 
 error[E0599]: no method named `string` found for type `ChildPropertiesBuilder<ChildPropertiesBuilderStep_missing_required_prop_int>` in the current scope
   --> $DIR/html-component-fail.rs:72:20

tests/macro/html-component-pass.rs

@@ -1,8 +1,8 @@
 #![recursion_limit = "256"]
 
 use std::marker::PhantomData;
-use yew::prelude::*;
 use yew::html::ChildrenRenderer;
+use yew::prelude::*;
 use yew::virtual_dom::{VChild, VNode};
 
 pub struct Generic<G> {
@@ -13,18 +13,30 @@ impl Component for Generic<String> {
     type Message = ();
     type Properties = ();
 
-    fn create(_: Self::Properties, _: ComponentLink<Self>) -> Self { unimplemented!() }
+    fn create(_: Self::Properties, _: ComponentLink<Self>) -> Self {
-    fn update(&mut self, _: Self::Message) -> ShouldRender { unimplemented!() }
+        unimplemented!()
-    fn view(&self) -> Html { unimplemented!() }
+    }
+    fn update(&mut self, _: Self::Message) -> ShouldRender {
+        unimplemented!()
+    }
+    fn view(&self) -> Html {
+        unimplemented!()
+    }
 }
 
 impl Component for Generic<Vec<String>> {
     type Message = ();
     type Properties = ();
 
-    fn create(_: Self::Properties, _: ComponentLink<Self>) -> Self { unimplemented!() }
+    fn create(_: Self::Properties, _: ComponentLink<Self>) -> Self {
-    fn update(&mut self, _: Self::Message) -> ShouldRender { unimplemented!() }
+        unimplemented!()
-    fn view(&self) -> Html { unimplemented!() }
+    }
+    fn update(&mut self, _: Self::Message) -> ShouldRender {
+        unimplemented!()
+    }
+    fn view(&self) -> Html {
+        unimplemented!()
+    }
 }
 
 #[derive(Clone, Properties, Default)]
@@ -39,9 +51,15 @@ impl Component for Container {
     type Message = ();
     type Properties = ContainerProperties;
 
-    fn create(_: Self::Properties, _: ComponentLink<Self>) -> Self { unimplemented!() }
+    fn create(_: Self::Properties, _: ComponentLink<Self>) -> Self {
-    fn update(&mut self, _: Self::Message) -> ShouldRender { unimplemented!() }
+        unimplemented!()
-    fn view(&self) -> Html { unimplemented!() }
+    }
+    fn update(&mut self, _: Self::Message) -> ShouldRender {
+        unimplemented!()
+    }
+    fn view(&self) -> Html {
+        unimplemented!()
+    }
 }
 
 #[derive(Clone)]
@@ -76,6 +94,7 @@ pub struct ChildProperties {
     pub string: String,
     #[props(required)]
     pub int: i32,
+    pub opt_str: Option<String>,
     pub vec: Vec<i32>,
     pub optional_callback: Option<Callback<()>>,
 }
@@ -85,9 +104,15 @@ impl Component for Child {
     type Message = ();
     type Properties = ChildProperties;
 
-    fn create(_: Self::Properties, _: ComponentLink<Self>) -> Self { unimplemented!() }
+    fn create(_: Self::Properties, _: ComponentLink<Self>) -> Self {
-    fn update(&mut self, _: Self::Message) -> ShouldRender { unimplemented!() }
+        unimplemented!()
-    fn view(&self) -> Html { unimplemented!() }
+    }
+    fn update(&mut self, _: Self::Message) -> ShouldRender {
+        unimplemented!()
+    }
+    fn view(&self) -> Html {
+        unimplemented!()
+    }
 }
 
 pub struct AltChild;
@@ -95,9 +120,15 @@ impl Component for AltChild {
     type Message = ();
     type Properties = ();
 
-    fn create(_: Self::Properties, _: ComponentLink<Self>) -> Self { unimplemented!() }
+    fn create(_: Self::Properties, _: ComponentLink<Self>) -> Self {
-    fn update(&mut self, _: Self::Message) -> ShouldRender { unimplemented!() }
+        unimplemented!()
-    fn view(&self) -> Html { unimplemented!() }
+    }
+    fn update(&mut self, _: Self::Message) -> ShouldRender {
+        unimplemented!()
+    }
+    fn view(&self) -> Html {
+        unimplemented!()
+    }
 }
 
 #[derive(Clone, Properties, Default)]
@@ -112,9 +143,15 @@ impl Component for ChildContainer {
     type Message = ();
     type Properties = ChildContainerProperties;
 
-    fn create(_: Self::Properties, _: ComponentLink<Self>) -> Self { unimplemented!() }
+    fn create(_: Self::Properties, _: ComponentLink<Self>) -> Self {
-    fn update(&mut self, _: Self::Message) -> ShouldRender { unimplemented!() }
+        unimplemented!()
-    fn view(&self) -> Html { unimplemented!() }
+    }
+    fn update(&mut self, _: Self::Message) -> ShouldRender {
+        unimplemented!()
+    }
+    fn view(&self) -> Html {
+        unimplemented!()
+    }
 }
 
 mod scoped {
@@ -158,6 +195,11 @@ fn compile_pass() {
             <Child int=1 vec={vec![1]} />
             <Child string={String::from("child")} int=1 />
 
+            <Child opt_str="child" int=1 />
+            <Child opt_str=String::from("child") int=1 />
+            <Child opt_str=Some("child") int=1 />
+            <Child opt_str=Some(String::from("child")) int=1 />
+
             // backwards compat
             <Child: string="child", int=3, />
         </>
@@ -172,6 +214,7 @@ fn compile_pass() {
         <>
             <Child int=1 />
             <Child int=1 optional_callback=Some(Callback::from(|_| ())) />
+            <Child int=1 optional_callback=Callback::from(|_| ()) />
             <Child int=1 optional_callback=None />
         </>
     };