From 1275305c55e213c720b83b6c1cbe248b8cba255f Mon Sep 17 00:00:00 2001
From: Crying Nights <cryingnights7v@qq.com>
Date: Thu, 7 May 2026 14:50:51 +0800
Subject: [PATCH] cgen: allow comparison between Option[T] and `none` literal
 (#27097)

---
 vlib/v/gen/c/infix.v                            |  2 +-
 vlib/v/tests/options/option_cast_eq_none_test.v | 17 +++++++++++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)
 create mode 100644 vlib/v/tests/options/option_cast_eq_none_test.v

diff --git a/vlib/v/gen/c/infix.v b/vlib/v/gen/c/infix.v
index 28b8f2b5a..b223f6a55 100644
--- a/vlib/v/gen/c/infix.v
+++ b/vlib/v/gen/c/infix.v
@@ -1754,7 +1754,7 @@ fn (mut g Gen) infix_expr_and_or_op(node ast.InfixExpr) {
 }
 
 fn (mut g Gen) gen_is_none_check(node ast.InfixExpr) {
-	if node.left in [ast.Ident, ast.SelectorExpr, ast.IndexExpr, ast.CallExpr, ast.CTempVar] {
+	if node.left in [ast.Ident, ast.SelectorExpr, ast.IndexExpr, ast.CallExpr, ast.CTempVar, ast.CastExpr] {
 		// When a sumtype variable has been comptime-smartcast to an option variant
 		// (e.g. `$if t is ?string { if t == none { ... } }`), we need to access the
 		// sumtype's variant field directly rather than using .data on the sumtype.
diff --git a/vlib/v/tests/options/option_cast_eq_none_test.v b/vlib/v/tests/options/option_cast_eq_none_test.v
new file mode 100644
index 000000000..0cd5225cd
--- /dev/null
+++ b/vlib/v/tests/options/option_cast_eq_none_test.v
@@ -0,0 +1,17 @@
+struct Foo {
+	x int
+}
+
+fn test_option_cast_eq_none() {
+	assert ?int(none) == none
+	assert !(?int(123) == none)
+	assert ?int(123) != none
+
+	assert ?string(none) == none
+	assert ?string('hi') != none
+
+	assert ?Foo(none) == none
+	assert ?Foo(Foo{
+		x: 1
+	}) != none
+}
-- 
2.39.5