calling "new" on a primitive value throw a type error (#825)

* calling "new" on a primitive value throw a type error

* fix format

boa/src/exec/tests.rs

@@ -754,6 +754,19 @@ mod in_operator {
         assert_eq!(forward(&mut engine, "bar.b"), "\"b\"");
     }
 
+    #[test]
+    fn should_type_error_when_new_is_not_constructor() {
+        let mut engine = Context::new();
+
+        let scenario = r#"
+            const a = "";
+            new a();
+        "#;
+
+        let result = forward(&mut engine, scenario);
+        assert_eq!(result, "Uncaught \"TypeError\": \"a is not a constructor\"");
+    }
+
     #[test]
     fn new_instance_should_point_to_prototype() {
         // A new instance should point to a prototype object created with the constructor function

boa/src/syntax/ast/node/new/mod.rs

@@ -55,7 +55,8 @@ impl Executable for New {
 
         match func_object {
             Value::Object(ref object) => object.construct(&v_args, interpreter),
-            _ => Ok(Value::undefined()),
+            _ => interpreter
+                .throw_type_error(format!("{} is not a constructor", self.expr().to_string(),)),
         }
     }
 }