From 98fd99944b8d6e4e457cba7e0ff984b5ee217685 Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Wed, 25 Mar 2026 16:42:23 +0300
Subject: [PATCH] checker: fix broken operator overloading for aliased arrays
 (fixes #23213)

---
 vlib/v/checker/infix.v                        |  6 ++++--
 ...ixed_array_operator_overloading_cmp_test.v | 20 +++++++++++++++++++
 2 files changed, 24 insertions(+), 2 deletions(-)
 create mode 100644 vlib/v/tests/aliases/alias_fixed_array_operator_overloading_cmp_test.v

diff --git a/vlib/v/checker/infix.v b/vlib/v/checker/infix.v
index a3d1b7dd6..6cdd158d4 100644
--- a/vlib/v/checker/infix.v
+++ b/vlib/v/checker/infix.v
@@ -593,14 +593,16 @@ fn (mut c Checker) infix_expr(mut node ast.InfixExpr) ast.Type {
 			}
 		}
 		.gt, .lt, .ge, .le {
+			cmp_method_name := '<'
 			unwrapped_left_type := c.unwrap_generic(left_type)
 			left_sym = c.table.sym(unwrapped_left_type)
-			if left_sym.kind == .alias && !left_sym.has_method_with_generic_parent(node.op.str()) {
+			if left_sym.kind == .alias && !left_sym.has_method_with_generic_parent(cmp_method_name) {
 				left_sym = c.table.final_sym(unwrapped_left_type)
 			}
 			unwrapped_right_type := c.unwrap_generic(right_type)
 			right_sym = c.table.sym(unwrapped_right_type)
-			if right_sym.kind == .alias && !right_sym.has_method_with_generic_parent(node.op.str()) {
+			if right_sym.kind == .alias
+				&& !right_sym.has_method_with_generic_parent(cmp_method_name) {
 				right_sym = c.table.final_sym(unwrapped_right_type)
 			}
 			if left_sym.kind in [.array, .array_fixed] && right_sym.kind in [.array, .array_fixed] {
diff --git a/vlib/v/tests/aliases/alias_fixed_array_operator_overloading_cmp_test.v b/vlib/v/tests/aliases/alias_fixed_array_operator_overloading_cmp_test.v
new file mode 100644
index 000000000..01dd061e7
--- /dev/null
+++ b/vlib/v/tests/aliases/alias_fixed_array_operator_overloading_cmp_test.v
@@ -0,0 +1,20 @@
+type Addr = [4]u8
+
+fn (a Addr) u32() u32 {
+	return (u32(a[0]) << 24) | (u32(a[1]) << 16) | (u32(a[2]) << 8) | u32(a[3])
+}
+
+fn (a Addr) < (b Addr) bool {
+	return a.u32() < b.u32()
+}
+
+fn test_fixed_array_alias_derived_comparison_operators_work() {
+	a := Addr([u8(1), 2, 3, 4]!)
+	b := Addr([u8(5), 4, 3, 2]!)
+
+	assert a < b
+	assert a <= b
+	assert b > a
+	assert b >= a
+	assert a != b
+}
-- 
2.39.5