From 1dd172e0809aad749b6e3e701220ce12ffcfa55c Mon Sep 17 00:00:00 2001
From: Felipe Pena <felipensp@gmail.com>
Date: Sat, 27 Sep 2025 13:58:54 -0300
Subject: [PATCH] cgen: fix option match case (fix #25360) (#25400)

---
 vlib/v/gen/c/infix.v                        |  3 +++
 vlib/v/tests/options/option_match_eq_test.v | 23 +++++++++++++++++++++
 2 files changed, 26 insertions(+)
 create mode 100644 vlib/v/tests/options/option_match_eq_test.v

diff --git a/vlib/v/gen/c/infix.v b/vlib/v/gen/c/infix.v
index e85beca4b..f58ce7931 100644
--- a/vlib/v/gen/c/infix.v
+++ b/vlib/v/gen/c/infix.v
@@ -344,6 +344,8 @@ fn (mut g Gen) infix_expr_eq_op(node ast.InfixExpr) {
 				if node.op == .ne {
 					g.write('!')
 				}
+				tmp_left_is_opt := g.left_is_opt
+				g.left_is_opt = true
 				g.write('${ptr_typ}_sumtype_eq(')
 				if left.typ.is_ptr() {
 					g.write('*'.repeat(left.typ.nr_muls()))
@@ -355,6 +357,7 @@ fn (mut g Gen) infix_expr_eq_op(node ast.InfixExpr) {
 				}
 				g.expr(node.right)
 				g.write(')')
+				g.left_is_opt = tmp_left_is_opt
 			}
 			.interface {
 				ptr_typ := g.equality_fn(left.unaliased)
diff --git a/vlib/v/tests/options/option_match_eq_test.v b/vlib/v/tests/options/option_match_eq_test.v
new file mode 100644
index 000000000..d8a9f3b44
--- /dev/null
+++ b/vlib/v/tests/options/option_match_eq_test.v
@@ -0,0 +1,23 @@
+module main
+
+enum Test {
+	a
+	b
+}
+
+type Sumtype = Test | int
+
+fn test_main() {
+	t := ?Sumtype(Test.a)
+	match true {
+		t == ?Sumtype(5) {
+			assert false
+		}
+		t == ?Sumtype(Test.a) {
+			assert true
+		}
+		else {
+			assert false
+		}
+	}
+}
-- 
2.39.5