From 6637013d795242ef2321015b66e7808a1b7e5159 Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Wed, 11 Mar 2026 15:38:14 +0300
Subject: [PATCH] cgen: error assignment from incompatible pointer type (fixes
 #18977)

---
 .../json2_map_to_any_cgen_regression_test.v   | 91 +++++++++++++++++++
 1 file changed, 91 insertions(+)
 create mode 100644 vlib/v/tests/sumtypes/json2_map_to_any_cgen_regression_test.v

diff --git a/vlib/v/tests/sumtypes/json2_map_to_any_cgen_regression_test.v b/vlib/v/tests/sumtypes/json2_map_to_any_cgen_regression_test.v
new file mode 100644
index 000000000..a6ecb73ad
--- /dev/null
+++ b/vlib/v/tests/sumtypes/json2_map_to_any_cgen_regression_test.v
@@ -0,0 +1,91 @@
+module main
+
+import x.json2
+
+struct RegressionReader {}
+
+fn (mut rd RegressionReader) read_map_len() !int {
+	return 1
+}
+
+fn (mut rd RegressionReader) read_string() !string {
+	return 'a'
+}
+
+fn (mut rd RegressionReader) read_reply() !json2.Any {
+	return json2.Any('b')
+}
+
+interface RegressionCmder {
+mut:
+	read_reply(mut rd RegressionReader) !
+}
+
+struct RegressionCmdableStateful {
+mut:
+	cmdable_stateful_function fn (mut cmd RegressionCmder) ! = unsafe { nil }
+}
+
+fn (c RegressionCmdableStateful) hello() !&RegressionMapStringAnyCmd {
+	mut cmd := new_regression_map_string_any_cmd('hello')
+	c.cmdable_stateful_function(mut cmd)!
+	return cmd
+}
+
+struct RegressionBaseCmd {
+	args []json2.Any
+}
+
+struct RegressionMapStringAnyCmd {
+	RegressionBaseCmd
+mut:
+	val json2.Any
+}
+
+fn new_regression_map_string_any_cmd(args ...json2.Any) &RegressionMapStringAnyCmd {
+	return &RegressionMapStringAnyCmd{
+		RegressionBaseCmd: RegressionBaseCmd{
+			args: args
+		}
+	}
+}
+
+fn (mut cmd RegressionMapStringAnyCmd) read_reply(mut rd RegressionReader) ! {
+	n := rd.read_map_len()!
+	mut new_map := map[string]json2.Any{}
+	for _ in 0 .. n {
+		k := rd.read_string()!
+		v := rd.read_reply() or {
+			if err.msg() == 'nil' {
+				new_map[k] = 'nil'
+				continue
+			}
+			return err
+		}
+		new_map[k] = v
+	}
+	cmd.val = new_map
+}
+
+@[heap]
+struct RegressionConnection {
+	RegressionCmdableStateful
+}
+
+fn new_regression_connection() &RegressionConnection {
+	mut c := &RegressionConnection{}
+	c.cmdable_stateful_function = c.process
+	return c
+}
+
+fn (mut c RegressionConnection) process(mut cmd RegressionCmder) ! {
+	mut rd := RegressionReader{}
+	cmd.read_reply(mut rd)!
+}
+
+fn test_json2_map_assignment_to_any_inside_mut_receiver_does_not_break_cgen() {
+	mut conn := new_regression_connection()
+	cmd := conn.hello()!
+	reply := cmd.val as map[string]json2.Any
+	assert reply['a']!.str() == 'b'
+}
-- 
2.39.5