[refactor] Remove duplicate definition of styling prop kind mapping

With rust-lang/rust#66507 merged, `Prop::kind_flags` can be `const fn`
and the `prop!` macro can use this method to get the kind flags for a
given prop.

Author: yvt

tcw3/src/lib.rs

@@ -8,6 +8,8 @@
 #![feature(weak_counts)]
 #![feature(doc_cfg)] // `cfg(rustdoc)`
 #![feature(unsized_locals)] // Call `dyn FnOnce`
+#![feature(const_if_match)] // `if` and `match` in `const fn`
+#![feature(const_fn)] // conditional expressions in `const fn`
 #![allow(clippy::float_cmp)]
 // this lint is ridiculous
 // The size on memory hardly relates to how they are passed via a parameter

tcw3/src/ui/theming/manager.rs

@@ -406,10 +406,7 @@ bitflags! {
 }
 
 impl Prop {
-    pub fn kind_flags(&self) -> PropKindFlags {
-        // Make sure to synchronize these with the `prop!` macro - This is a
-        // temporary restriction until `match` inside `const fn` is implemented:
-        // <https://github.com/rust-lang/rust/issues/49146>
+    pub const fn kind_flags(&self) -> PropKindFlags {
         match *self {
             Prop::NumLayers => PropKindFlags::LAYER_ALL,
             Prop::LayerImg(_) => PropKindFlags::LAYER_IMG,

tcw3/src/ui/theming/stylesheet.rs

@@ -239,15 +239,12 @@ macro_rules! sel {
 
 /// This macro is used for two purposes:
 ///  - To create `PropKindFlags`.
-///    (`Prop` and `Prop::kind_flags` would be better for normalization, but
-///     `match` does not work inside a `const fn` yet...
-///     <https://github.com/rust-lang/rfcs/pull/2342>)
 ///  - To create `(Prop, PropValue)`.
 #[doc(hidden)]
 #[macro_export]
 macro_rules! prop {
     (@kind num_layers) => {
-        $crate::ui::theming::PropKindFlags::LAYER_ALL
+        $crate::ui::theming::Prop::NumLayers.kind_flags()
     };
     (num_layers: $val:expr) => {
         (
@@ -257,7 +254,7 @@ macro_rules! prop {
     };
 
     (@kind layer_img[$i:expr]) => {
-        $crate::ui::theming::PropKindFlags::LAYER_IMG
+        $crate::ui::theming::Prop::LayerImg($i).kind_flags()
     };
     (layer_img[$i:expr]: $val:expr) => {
         (
@@ -267,7 +264,7 @@ macro_rules! prop {
     };
 
     (@kind layer_center[$i:expr]) => {
-        $crate::ui::theming::PropKindFlags::LAYER_CENTER
+        $crate::ui::theming::Prop::LayerCenter($i).kind_flags()
     };
     (layer_center[$i:expr]: $val:expr) => {
         (
@@ -277,7 +274,7 @@ macro_rules! prop {
     };
 
     (@kind layer_opacity[$i:expr]) => {
-        $crate::ui::theming::PropKindFlags::LAYER_OPACITY
+        $crate::ui::theming::Prop::LayerOpacity($i).kind_flags()
     };
     (layer_opacity[$i:expr]: $val:expr) => {
         (
@@ -287,7 +284,7 @@ macro_rules! prop {
     };
 
     (@kind layer_bg_color[$i:expr]) => {
-        $crate::ui::theming::PropKindFlags::LAYER_BG_COLOR
+        $crate::ui::theming::Prop::LayerBgColor($i).kind_flags()
     };
     (layer_bg_color[$i:expr]: $val:expr) => {
         (
@@ -297,7 +294,7 @@ macro_rules! prop {
     };
 
     (@kind layer_metrics[$i:expr]) => {
-        $crate::ui::theming::PropKindFlags::LAYER_BOUNDS
+        $crate::ui::theming::Prop::LayerMetrics($i).kind_flags()
     };
     (layer_metrics[$i:expr]: $val:expr) => {
         (
@@ -307,7 +304,7 @@ macro_rules! prop {
     };
 
     (@kind subview_metrics[$i:expr]) => {
-        $crate::ui::theming::PropKindFlags::LAYOUT
+        $crate::ui::theming::Prop::SubviewMetrics($i).kind_flags()
     };
     (subview_metrics[$i:expr]: $val:expr) => {
         (
@@ -317,7 +314,7 @@ macro_rules! prop {
     };
 
     (@kind min_size) => {
-        $crate::ui::theming::PropKindFlags::LAYOUT
+        $crate::ui::theming::Prop::MinSize.kind_flags()
     };
     (min_size: $val:expr) => {
         (
@@ -327,7 +324,7 @@ macro_rules! prop {
     };
 
     (@kind fg_color) => {
-        $crate::ui::theming::PropKindFlags::FG_COLOR
+        $crate::ui::theming::Prop::FgColor.kind_flags()
     };
     (fg_color: $val:expr) => {
         (