Fixed property in when assign validation.

TODO/_current.md

@@ -1,5 +1,7 @@
 # Widget & Property Refactor
 
+* Refactor `defaults!` and `properties!` to be proc-macros directly.
+    - The `macro_rules!` indirection causes the error span to be inside the macro instead of the call site..
 * Refactor `#[widget]`.
     - Test build error for parent not a widget.
     - Where is `widget_new!` available for the widget macro?

zero-ui-core/src/tests/widget.rs

@@ -335,12 +335,12 @@ impl MultiWhenWgt {
     fn on_start(&mut self) {
         defaults! {
             self;
-            util::trace = "default";
+            util::live_trace = "default";
             when *#util::is_state {
-                util::trace = "state_0";
+                util::live_trace = "state_0";
             }
             when *#util::is_state {
-                util::trace = "state_1";
+                util::live_trace = "state_1";
             }
         }
     }

zero-ui-proc-macros/src/widget.rs

@@ -599,6 +599,20 @@ fn prop_assign(prop: &WgtProperty, errors: &mut Errors, is_when: bool) -> TokenS
         }
     }
 
+    let ident_meta = ident_spanned!(ident.span()=> "{}_meta__", ident);
+
+    let when_check = if is_when {
+        let meta = quote_call!(#ident_meta());
+        quote! {
+            {
+                let meta__ = #meta
+                meta__.allowed_in_when_assign();
+            }
+        }
+    } else {
+        quote!()
+    };
+
     let prop_init;
 
     match &prop.value {
@@ -625,7 +639,6 @@ fn prop_assign(prop: &WgtProperty, errors: &mut Errors, is_when: bool) -> TokenS
                 let idents = fields.iter().map(|f| &f.ident);
                 let values = fields.iter().map(|f| &f.expr);
                 let ident_sorted = ident_spanned!(ident.span()=> "{}_sorted__", ident);
-                let ident_meta = ident_spanned!(ident.span()=> "{}_meta__", ident);
 
                 let call = quote_call! {
                     #ident_sorted(#(#idents_sorted),*)
@@ -665,6 +678,7 @@ fn prop_assign(prop: &WgtProperty, errors: &mut Errors, is_when: bool) -> TokenS
 
     quote! {
         #attrs {
+            #when_check
             #custom_expand
             #prop_init
         }