add compile test for unsound case

packages/core/compile_tests/props_safety.rs

@@ -0,0 +1,32 @@
+use dioxus::prelude::*;
+
+fn main() {}
+
+fn app(cx: Scope) -> Element {
+    let count: &RefCell<Vec<Element>> = cx.use_hook(|| RefCell::new(Vec::new()));
+
+    render! {
+        unsafe_child_component {
+            borrowed: count
+        }
+    }
+}
+
+#[derive(Props)]
+struct Testing<'a> {
+    borrowed: &'a RefCell<Vec<Element<'a>>>,
+}
+
+fn unsafe_child_component<'a>(cx: Scope<'a, Testing<'a>>) -> Element<'a> {
+    let Testing { borrowed } = cx.props;
+    let borrowed_temporary_data =
+        cx.use_hook(|| String::from("This data is only valid for the lifetime of the child"));
+
+    borrowed
+        .borrow_mut()
+        .push(render! {"{borrowed_temporary_data}"});
+
+    cx.render(rsx! {
+        div { "Hello, world!" }
+    })
+}

packages/core/compile_tests/props_safety.stderr

@@ -0,0 +1,20 @@
+error[E0521]: borrowed data escapes outside of function
+  --> compile_tests/props_safety.rs:8:5
+   |
+5  |   fn app(cx: Scope) -> Element {
+   |          --
+   |          |
+   |          `cx` is a reference that is only valid in the function body
+   |          has type `&'1 Scoped<'1>`
+...
+8  | /     render! {
+9  | |         unsafe_child_component {
+10 | |             borrowed: count
+11 | |         }
+12 | |     }
+   | |     ^
+   | |     |
+   | |_____`cx` escapes the function body here
+   |       argument requires that `'1` must outlive `'static`
+   |
+   = note: this error originates in the macro `render` (in Nightly builds, run with -Z macro-backtrace for more info)