From 29e962749a17d85c52d72b7d29d808cf74d55c02 Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Wed, 11 Mar 2026 13:54:18 +0300
Subject: [PATCH] cgen: incorrect Auto De-referencing of &net.TcpConn in Map
 Access (fixes #21067)

---
 vlib/v/debug/tests/map_nested_ref_mut.expect  |  9 +++++++++
 vlib/v/debug/tests/map_nested_ref_mut.vv      | 12 ++++++++++++
 .../map_nested_reference_value_test.v         | 19 +++++++++++++++++++
 3 files changed, 40 insertions(+)
 create mode 100644 vlib/v/debug/tests/map_nested_ref_mut.expect
 create mode 100644 vlib/v/debug/tests/map_nested_ref_mut.vv
 create mode 100644 vlib/v/tests/builtin_maps/map_nested_reference_value_test.v

diff --git a/vlib/v/debug/tests/map_nested_ref_mut.expect b/vlib/v/debug/tests/map_nested_ref_mut.expect
new file mode 100644
index 000000000..171ca6c0f
--- /dev/null
+++ b/vlib/v/debug/tests/map_nested_ref_mut.expect
@@ -0,0 +1,9 @@
+#!/usr/bin/env expect
+source "common.tcl"
+
+expect "Break on *main* main in ${test_file}:9\r\n"
+expect "${test_file}:9 vdbg> "
+send "p connection\n"
+expect "connection = * (&net.TcpConn)"
+send "q\n"
+expect eof
diff --git a/vlib/v/debug/tests/map_nested_ref_mut.vv b/vlib/v/debug/tests/map_nested_ref_mut.vv
new file mode 100644
index 000000000..0f119a534
--- /dev/null
+++ b/vlib/v/debug/tests/map_nested_ref_mut.vv
@@ -0,0 +1,12 @@
+import net
+
+fn main() {
+	mut con_list := map[string]map[string]&net.TcpConn{}
+	con_list['foo'] = {
+		'bar': &net.TcpConn{}
+	}
+	for _, mut connection in unsafe { con_list['foo'] } {
+		$dbg;
+		dump(connection)
+	}
+}
diff --git a/vlib/v/tests/builtin_maps/map_nested_reference_value_test.v b/vlib/v/tests/builtin_maps/map_nested_reference_value_test.v
new file mode 100644
index 000000000..0504f3a1e
--- /dev/null
+++ b/vlib/v/tests/builtin_maps/map_nested_reference_value_test.v
@@ -0,0 +1,19 @@
+import net
+
+fn accept_mut_tcp_conn(mut conn net.TcpConn) bool {
+	return true
+}
+
+fn test_nested_map_tcpconn_reference_value_for_in_mut_type() {
+	mut con_list := map[string]map[string]&net.TcpConn{}
+	conn := &net.TcpConn{}
+	con_list['foo'] = {
+		'bar': conn
+	}
+
+	for _, mut connection in unsafe { con_list['foo'] } {
+		assert typeof(connection).name == '&net.TcpConn'
+		assert accept_mut_tcp_conn(mut connection)
+		assert voidptr(connection) == voidptr(conn)
+	}
+}
-- 
2.39.5