Forbid shadowing of state variable.

CHANGELOG.md

@@ -26,6 +26,7 @@ Enhancements
 
 * Variable definitions are optimized so that shadowed variables are reused as much as possible to reduce memory consumption.
 * `FnAccess` and `FnNamespace` now implement `Ord` and `PartialOrd`.
+* The `event_handler_map` example is enhanced to prevent shadowing of the state object map.
 
 
 Version 1.5.0

examples/event_handler_map/main.rs

@@ -56,7 +56,11 @@ pub fn main() {
     };
 
     // Create Engine
-    let engine = Engine::new();
+    let mut engine = Engine::new();
+
+    // Prevent shadowing of `state`
+    #[allow(deprecated)]
+    engine.on_def_var(|_, info, _| Ok(info.name != "state"));
 
     // Create a custom 'Scope' to hold state
     let mut scope = Scope::new();

src/bin/rhai-run.rs

@@ -47,6 +47,7 @@ fn main() {
             },
         };
 
+        // Initialize scripting engine
         let mut engine = Engine::new();
 
         #[cfg(not(feature = "no_optimize"))]