Updated TODO added another test for allowed_in_when validation.

TODO.md

@@ -4,11 +4,10 @@
 
 Things that must be done first because they influence the core API design that is used to do all the rest.
 
-* Implement validation for inherit overrides changing captured properties.
 * Change capture-only in widget declaration to need type tokens in a tt group, improve validation after doing this.
-* What to do with capture-only in mix-ins?
-* Replace the `implicit_mixin` with a `base_widget`?
 * Custom default property values, `#[property(context, default <see macro_design.rs>)]`.
+* Improve property allowed_in_when validation for generics, generate a `new` like call for each
+  argument, instead of all at once.
 * Test `#[cfg(..)]` support in widget declarations.
 * Use something like this [https://docs.rs/crate/xss-probe/0.2.0/source/build.rs] to patch docs.
 * Link property declaration to their source-code point.

tests/build/fail/property/allowed_in_when_validation_back_to_args.rs

@@ -0,0 +1,20 @@
+use zero_ui::core::{property, var::IntoVar, UiNode};
+
+#[derive(Clone)]
+pub struct MyType;
+impl IntoVar<bool> for MyType {
+    type Var = zero_ui::core::var::OwnedVar<bool>;
+
+    fn into_var(self) -> Self::Var {
+        zero_ui::core::var::OwnedVar(true)
+    }
+}
+
+#[property(context)]
+pub fn invalid(child: impl UiNode, value: MyType) -> impl UiNode {
+    let _ = value;
+    // for allowed_in_when, the arg type needs to be IntoVar AND accept the resulting var back.
+    child
+}
+
+fn main() {}

tests/build/fail/property/allowed_in_when_validation_back_to_args.stderr

@@ -0,0 +1,8 @@
+error[E0308]: mismatched types
+  --> $DIR/allowed_in_when_validation_back_to_args.rs:14:43
+   |
+14 | pub fn invalid(child: impl UiNode, value: MyType) -> impl UiNode {
+   |                                           ^^^^^^ expected struct `MyType`, found struct `OwnedVar`
+   |
+   = note: expected struct `MyType`
+              found struct `OwnedVar<bool>`