From 78eeed6834acdc5839f6e80dd5c037d1a27fe000 Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Wed, 25 Mar 2026 16:42:20 +0300
Subject: [PATCH] checker: fix referenced operator overloading not working
 (fixes #15551)

---
 vlib/v/checker/infix.v                        | 22 ++++++++++---------
 ...overloading_with_reference_operands_test.v | 21 ++++++++++++++++++
 2 files changed, 33 insertions(+), 10 deletions(-)

diff --git a/vlib/v/checker/infix.v b/vlib/v/checker/infix.v
index 60424a3ee..a3d1b7dd6 100644
--- a/vlib/v/checker/infix.v
+++ b/vlib/v/checker/infix.v
@@ -15,6 +15,12 @@ fn infix_expr_is_nil_like(expr ast.Expr) bool {
 	return expr.is_nil() || (expr is ast.UnsafeExpr && expr.expr.is_nil())
 }
 
+fn has_matching_reference_operator_overload(sym &ast.TypeSymbol, op string, receiver_type ast.Type, operand_type ast.Type) bool {
+	method := sym.find_method_with_generic_parent(op) or { return false }
+	return method.params.len == 2 && method.params[0].typ == receiver_type
+		&& method.params[1].typ == operand_type
+}
+
 fn (mut c Checker) infix_expr(mut node ast.InfixExpr) ast.Type {
 	former_expected_type := c.expected_type
 	defer {
@@ -188,17 +194,13 @@ fn (mut c Checker) infix_expr(mut node ast.InfixExpr) ast.Type {
 	if left_type.is_any_kind_of_pointer() && !left_type.has_flag(.shared_f)
 		&& !node.left.is_auto_deref_var()
 		&& node.op in [.plus, .minus, .mul, .div, .mod, .xor, .amp, .pipe] {
-		if !c.pref.translated && ((right_type.is_any_kind_of_pointer() && node.op != .minus)
+		if has_matching_reference_operator_overload(left_sym, node.op.str(), left_type,
+			right_type)
+		{
+			// allow explicit operator overloads like `fn (x &Type) OP (y &Type) ReturnType {`
+		} else if !c.pref.translated && ((right_type.is_any_kind_of_pointer() && node.op != .minus)
 			|| (!right_type.is_any_kind_of_pointer() && node.op !in [.plus, .minus])) {
-			if _ := left_sym.find_method(node.op.str()) {
-				if left_sym.kind == .alias && right_sym.kind == .alias {
-					// allow an explicit operator override `fn (x &AliasType) OP (y &AliasType) &AliasType {`
-				} else {
-					c.invalid_operator_error(node.op, left_type, right_type, left_right_pos)
-				}
-			} else {
-				c.invalid_operator_error(node.op, left_type, right_type, left_right_pos)
-			}
+			c.invalid_operator_error(node.op, left_type, right_type, left_right_pos)
 		} else if node.op in [.plus, .minus] {
 			if !c.inside_unsafe && !node.left.is_auto_deref_var() && !node.right.is_auto_deref_var() {
 				if !c.pref.translated && !c.file.is_translated {
diff --git a/vlib/v/tests/structs/operator_overloading_with_reference_operands_test.v b/vlib/v/tests/structs/operator_overloading_with_reference_operands_test.v
index 6c5db2a87..9c43aab6b 100644
--- a/vlib/v/tests/structs/operator_overloading_with_reference_operands_test.v
+++ b/vlib/v/tests/structs/operator_overloading_with_reference_operands_test.v
@@ -45,3 +45,24 @@ fn test_eq_operator_with_reference_operands() {
 	}
 	assert false
 }
+
+struct Sum {
+	value int
+}
+
+fn (a &Sum) + (b &Sum) &Sum {
+	return &Sum{
+		value: a.value + b.value
+	}
+}
+
+fn test_plus_operator_with_reference_operands() {
+	a := &Sum{
+		value: 2
+	}
+	b := &Sum{
+		value: 3
+	}
+	c := a + b
+	assert c.value == 5
+}
-- 
2.39.5