Propagate constants to functions for Engine::XXX_with_scope calls.

tests/optimizer.rs

@@ -1,6 +1,6 @@
 #![cfg(not(feature = "no_optimize"))]
 
-use rhai::{Engine, EvalAltResult, OptimizationLevel, INT};
+use rhai::{Engine, EvalAltResult, OptimizationLevel, Scope, INT};
 
 #[test]
 fn test_optimizer() -> Result<(), Box<EvalAltResult>> {
@@ -107,3 +107,24 @@ fn test_optimizer_parse() -> Result<(), Box<EvalAltResult>> {
 
     Ok(())
 }
+
+#[test]
+fn test_optimizer_scope() -> Result<(), Box<EvalAltResult>> {
+    let engine = Engine::new();
+    let mut scope = Scope::new();
+
+    scope.push_constant("FOO", 42 as INT);
+
+    let ast = engine.compile_with_scope(&scope, "fn foo() { FOO } foo()")?;
+
+    scope.push("FOO", 123 as INT);
+
+    assert_eq!(engine.eval_ast::<INT>(&ast)?, 42);
+    assert_eq!(engine.eval_ast_with_scope::<INT>(&mut scope, &ast)?, 42);
+
+    let ast = engine.compile_with_scope(&scope, "fn foo() { FOO } foo()")?;
+
+    assert!(engine.eval_ast_with_scope::<INT>(&mut scope, &ast).is_err());
+
+    Ok(())
+}