fix: Convert rust tuples such that they can be used polymorphically

Fixes #848

Author: Marwes

tests/api.rs

@@ -339,6 +339,18 @@ fn use_type_from_type_field() {
     assert_eq!(actual, Test::B("abc".to_string()));
 }
 
+#[test]
+fn use_rust_created_tuple_as_polymorphic() {
+    let _ = ::env_logger::try_init();
+    let test = r"\x -> x._0";
+    let mut vm = make_vm();
+    load_script(&mut vm, "test", test).unwrap_or_else(|err| panic!("{}", err));
+
+    let mut f: FunctionRef<fn((i32, String)) -> VmInt> = vm.get_global("test").unwrap();
+    let result = f.call((1, "".to_string())).unwrap();
+    assert_eq!(result, 1);
+}
+
 #[test]
 fn use_rust_created_record_as_polymorphic() {
     let _ = ::env_logger::try_init();

vm/src/api/mod.rs

@@ -1687,7 +1687,13 @@ macro_rules! define_tuple {
                     $id.push(context)?;
                 )+
                 let len = count!($($id),+);
-                context.context().push_new_data(0, len)?;
+                let thread = context.thread();
+                #[allow(unused_assignments)]
+                let field_names = {
+                    let mut i = 0;
+                    [$(thread.global_env().intern(&format!("_{}", { let _ = $id; let x = i; i += 1; x }))?),*]
+                };
+                context.context().push_new_record(len, &field_names)?;
                 Ok(())
             }
         }