fix: object iadd call with standalone imutable

src/value/refvalue.rs

@@ -277,7 +277,7 @@ impl RefValue {
         // When a type name was emitted, try to call builtin-function for operation
         if let Some(name) = name {
             match Builtin::get_method(name, op) {
-                Ok(builtin) => return Ok(builtin.call(None, vec![self, operand])?.unwrap()),
+                Ok(builtin) => return Ok(builtin.call(None, vec![self, operand.ref_or_copy()])?.unwrap()),
                 // default "inline" operation is the non-inline operation assigning the result to itself
                 Err(_) if op.starts_with("i") => {}
                 Err(err) => return Err(err),

tests/list_add.tok

@@ -21,6 +21,20 @@ l = (1,)
 l + (2, 3)
 l
 
+# iadd with imutable object
+l = ,
+i = 0
+l += i
+l, ++i
+
+# iadd with mutable object
+l = ,
+m = 1,2,3
+l += m
+l += m,
+m += 4
+l
+
 #---
 
 #(1, 2, 3, 4)
@@ -33,3 +47,7 @@ l
 
 #(1, 2, 3)
 #(1, )
+
+#((0, ), 1)
+
+#(1, 2, 3, (1, 2, 3, 4))