Add #[cfg] support in submodules

codegen/ui_tests/rhai_mod_inner_cfg_false.rs

@@ -0,0 +1,29 @@
+use rhai::plugin::*;
+
+#[derive(Clone)]
+pub struct Point {
+    x: f32,
+    y: f32,
+}
+
+#[export_module]
+pub mod test_module {
+    #[cfg(feature = "unset_feature")]
+    pub mod test_mod {
+        pub fn test_fn(input: Point) -> bool {
+            input.x > input.y
+        }
+    }
+}
+
+fn main() {
+    let n = Point {
+        x: 0.0,
+        y: 10.0,
+    };
+    if test_module::test_mod::test_fn(n) {
+        println!("yes");
+    } else {
+        println!("no");
+    }
+}

codegen/ui_tests/rhai_mod_inner_cfg_false.stderr

@@ -0,0 +1,5 @@
+error[E0433]: failed to resolve: could not find `test_mod` in `test_module`
+  --> $DIR/rhai_mod_inner_cfg_false.rs:24:21
+   |
+24 |     if test_module::test_mod::test_fn(n) {
+   |                     ^^^^^^^^ could not find `test_mod` in `test_module`