From b98ca31e263a4319839543088accd45915290866 Mon Sep 17 00:00:00 2001
From: Felipe Pena <felipensp@gmail.com>
Date: Sat, 26 Apr 2025 12:11:31 -0300
Subject: [PATCH] cgen: fix codegen for writing on unwrapped selector (fix
 #24316) (#24323)

---
 vlib/v/gen/c/cgen.v                           | 17 ++++---
 vlib/v/tests/options/option_ptr_unwrap_test.v |  1 -
 .../option_unwrap_selector_write_test.v       | 46 +++++++++++++++++++
 3 files changed, 54 insertions(+), 10 deletions(-)
 create mode 100644 vlib/v/tests/options/option_unwrap_selector_write_test.v

diff --git a/vlib/v/gen/c/cgen.v b/vlib/v/gen/c/cgen.v
index fe09c02e1..c1b299ed8 100644
--- a/vlib/v/gen/c/cgen.v
+++ b/vlib/v/gen/c/cgen.v
@@ -4147,11 +4147,13 @@ fn (mut g Gen) selector_expr(node ast.SelectorExpr) {
 	mut field_typ := ast.void_type
 	mut is_option_unwrap := false
 	is_iface_or_sumtype := sym.kind in [.interface, .sum_type]
+	mut deref_count := 0
 	if f := g.table.find_field_with_embeds(sym, node.field_name) {
 		field_sym := g.table.sym(f.typ)
 		field_typ = f.typ
 		if is_iface_or_sumtype {
 			g.write('(*(')
+			deref_count++
 		}
 		is_option := field_typ.has_flag(.option)
 		if field_sym.kind in [.sum_type, .interface] || is_option {
@@ -4168,6 +4170,7 @@ fn (mut g Gen) selector_expr(node ast.SelectorExpr) {
 					}
 					if nested_unwrap && field_sym.kind == .sum_type {
 						g.write('*(')
+						deref_count++
 					}
 					for i, typ in field.smartcasts {
 						if i == 0 && (is_option_unwrap || nested_unwrap) {
@@ -4184,14 +4187,9 @@ fn (mut g Gen) selector_expr(node ast.SelectorExpr) {
 							} else {
 								'*'
 							}
-							suffix := if g.inside_selector && field.orig_type.has_flag(.option)
-								&& field.orig_type.is_ptr() && g.is_assign_lhs {
-								''
-							} else {
-								'*'
-							}
-							g.inside_selector_deref = suffix == '' && deref.len > 0
-							g.write('(${deref}(${g.styp(typ)}${suffix})')
+							deref_count += deref.len
+							g.inside_selector_deref = deref_count > typ.nr_muls()
+							g.write('(${deref}(${g.styp(typ)}*)')
 						}
 						if i == 0 || !nested_unwrap {
 							g.write('(')
@@ -4361,7 +4359,8 @@ fn (mut g Gen) selector_expr(node ast.SelectorExpr) {
 		|| (((!is_dereferenced && unwrapped_expr_type.is_ptr()) || sym.kind == .chan
 		|| alias_to_ptr) && node.from_embed_types.len == 0)
 		|| (node.expr.is_as_cast() && g.inside_smartcast)
-	if !has_embed && left_is_ptr && !(opt_ptr_already_deref && !g.inside_selector) {
+		|| (!opt_ptr_already_deref && unwrapped_expr_type.is_ptr())
+	if !has_embed && left_is_ptr {
 		g.write('->')
 	} else {
 		g.write('.')
diff --git a/vlib/v/tests/options/option_ptr_unwrap_test.v b/vlib/v/tests/options/option_ptr_unwrap_test.v
index 74ff2829e..4e10a054a 100644
--- a/vlib/v/tests/options/option_ptr_unwrap_test.v
+++ b/vlib/v/tests/options/option_ptr_unwrap_test.v
@@ -1,4 +1,3 @@
-// vtest build: !msvc
 import time
 // 41s.
 
diff --git a/vlib/v/tests/options/option_unwrap_selector_write_test.v b/vlib/v/tests/options/option_unwrap_selector_write_test.v
new file mode 100644
index 000000000..75ec74b1a
--- /dev/null
+++ b/vlib/v/tests/options/option_unwrap_selector_write_test.v
@@ -0,0 +1,46 @@
+module main
+
+@[heap]
+interface IGameObject {
+mut:
+	name       string
+	parent     ?&IGameObject
+	next       ?&IGameObject
+	child      ?&IGameObject
+	last_child ?&IGameObject
+	add_child(mut o IGameObject)
+}
+
+@[heap]
+struct GameObject implements IGameObject {
+mut:
+	name       string
+	parent     ?&IGameObject
+	next       ?&IGameObject
+	child      ?&IGameObject
+	last_child ?&IGameObject
+}
+
+fn (mut gameobject GameObject) add_child(mut o IGameObject) {
+	o.parent = gameobject
+	if gameobject.last_child != none {
+		gameobject.last_child.next = o
+	} else {
+		gameobject.child = o
+	}
+	gameobject.last_child = o
+}
+
+fn test_main() {
+	mut v1 := &GameObject{
+		name: 'v1'
+	}
+	mut v2 := &GameObject{
+		name: 'v2'
+	}
+	mut v3 := &GameObject{
+		name: 'v3'
+	}
+	v1.add_child(mut v2)
+	v1.add_child(mut v3)
+}
-- 
2.39.5