Fix compilation when some features are disabled

.github/workflows/main.yml

@@ -47,7 +47,7 @@ jobs:
         uses: Swatinem/rust-cache@v2
 
       - name: Clippy
-        run: cargo clippy --tests --examples -- -D warnings
+        run: cargo clippy --all-features --tests --examples -- -D warnings
 
       - name: Rustdoc
         run: cargo rustdoc -- -D warnings
@@ -68,6 +68,25 @@ jobs:
       - name: Test doc
         run: cargo test --no-default-features --doc
 
+  feature-combinations:
+    name: Feature combinations
+    runs-on: ubuntu-latest
+    steps:
+      - name: Clone repo
+        uses: actions/checkout@v4
+
+      - name: Instal stable toolchain
+        uses: dtolnay/rust-toolchain@stable
+
+      - name: Cache crates
+        uses: Swatinem/rust-cache@v2
+
+      - name: Install Cargo Hack
+        run: cargo install cargo-hack
+
+      - name: Check feature combinations
+        run: cargo hack check --feature-powerset
+
   test:
     name: Test
     runs-on: ubuntu-latest

src/input_reader.rs

@@ -1,3 +1,5 @@
+use std::marker::PhantomData;
+
 use bevy::{
     ecs::system::SystemParam,
     input::{
@@ -238,6 +240,8 @@ impl InputReader<'_, '_> {
 
 #[derive(SystemParam)]
 pub struct UiInput<'w, 's> {
+    /// Marker to make the struct compile even when all features are disabled.
+    marker: PhantomData<(&'w (), &'s ())>,
     #[cfg(feature = "ui_priority")]
     interactions: Query<'w, 's, &'static Interaction>,
     #[cfg(feature = "egui_priority")]