Fix bug with eager optimization of method calls.

tests/method_call.rs

@@ -2,23 +2,23 @@
 
 use rhai::{Engine, EvalAltResult, INT};
 
+#[derive(Debug, Clone, Eq, PartialEq)]
+struct TestStruct {
+    x: INT,
+}
+
+impl TestStruct {
+    fn update(&mut self, n: INT) {
+        self.x += n;
+    }
+
+    fn new() -> Self {
+        Self { x: 1 }
+    }
+}
+
 #[test]
 fn test_method_call() -> Result<(), Box<EvalAltResult>> {
-    #[derive(Debug, Clone, Eq, PartialEq)]
-    struct TestStruct {
-        x: INT,
-    }
-
-    impl TestStruct {
-        fn update(&mut self, n: INT) {
-            self.x += n;
-        }
-
-        fn new() -> Self {
-            Self { x: 1 }
-        }
-    }
-
     let mut engine = Engine::new();
 
     engine
@@ -47,3 +47,31 @@ fn test_method_call_style() -> Result<(), Box<EvalAltResult>> {
 
     Ok(())
 }
+
+#[cfg(not(feature = "no_optimize"))]
+#[test]
+fn test_method_call_with_full_optimization() -> Result<(), Box<EvalAltResult>> {
+    let mut engine = Engine::new();
+
+    engine.set_optimization_level(rhai::OptimizationLevel::Full);
+
+    engine
+        .register_fn("new_ts", || TestStruct::new())
+        .register_fn("ymd", |_: INT, _: INT, _: INT| 42 as INT)
+        .register_fn("range", |_: &mut TestStruct, _: INT, _: INT| {
+            TestStruct::new()
+        });
+
+    assert_eq!(
+        engine.eval::<TestStruct>(
+            "
+                let xs = new_ts();
+                let ys = xs.range(ymd(2022, 2, 1), ymd(2022, 2, 2));
+                ys
+            "
+        )?,
+        TestStruct::new()
+    );
+
+    Ok(())
+}