Use std::any::type_name

tests/mismatched_op.rs

@@ -1,4 +1,4 @@
-use rhai::{Engine, EvalAltResult};
+use rhai::{Engine, EvalAltResult, RegisterFn};
 
 #[test]
 fn test_mismatched_op() {
@@ -7,7 +7,32 @@ fn test_mismatched_op() {
     assert_eq!(
         engine.eval::<i64>("60 + \"hello\""),
         Err(EvalAltResult::ErrorFunctionNotFound(
-            "+ (integer,string)".into()
+            "+ (i64,alloc::string::String)".into()
+        ))
+    );
+}
+
+#[test]
+fn test_mismatched_op_custom_type() {
+    #[derive(Clone)]
+    struct TestStruct {
+        x: i64,
+    }
+
+    impl TestStruct {
+        fn new() -> TestStruct {
+            TestStruct { x: 1 }
+        }
+    }
+
+    let mut engine = Engine::new();
+    engine.register_type::<TestStruct>();
+    engine.register_fn("new_ts", TestStruct::new);
+
+    assert_eq!(
+        engine.eval::<i64>("60 + new_ts()"),
+        Err(EvalAltResult::ErrorFunctionNotFound(
+            "+ (i64,mismatched_op::test_mismatched_op_custom_type::TestStruct)".into()
         ))
     );
 }