checker: fix option ptr field assign checking (fix #23879) (#23880)

vlib/v/checker/struct.v

@@ -713,8 +713,7 @@ fn (mut c Checker) struct_init(mut node ast.StructInit, is_field_zero_struct_ini
 				if got_type.has_flag(.result) {
 					c.check_expr_option_or_result_call(init_field.expr, init_field.typ)
 				}
-				if exp_type_is_option && got_type.is_ptr() && !(exp_type.is_ptr()
-					&& exp_type_sym.kind == .struct) {
+				if exp_type_is_option && got_type.is_ptr() && !exp_type.is_ptr() {
 					c.error('cannot assign a pointer to option struct field', init_field.pos)
 				}
 				if exp_type_sym.kind == .voidptr && got_type_sym.kind == .struct

vlib/v/tests/options/option_ptr_field_test.v

@@ -0,0 +1,40 @@
+module main
+
+@[heap]
+interface IGameObject {
+mut:
+	name   string
+	parent ?&IGameObject
+}
+
+@[heap]
+struct GameObject implements IGameObject {
+mut:
+	name   string
+	parent ?&IGameObject
+}
+
+struct Ship implements IGameObject {
+	GameObject
+	speed f32
+}
+
+fn test_main() {
+	mut world := &GameObject{
+		name: 'world'
+	}
+	mut ship := &Ship{
+		name:   'ship'
+		parent: world
+	}
+	assert '${ship}' == "&Ship{
+    GameObject: GameObject{
+        name: 'ship'
+        parent: &Option(IGameObject(GameObject{
+            name: 'world'
+            parent: &Option(none)
+        }))
+    }
+    speed: 0.0
+}"
+}