From 1c40b6fd4a0a9d04ebf516b3d3fb61819fc22461 Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Thu, 26 Feb 2026 19:45:07 +0300
Subject: [PATCH] json2: fix alias type of json2.Any can't decode json used as
 generic (fixes #24127)

---
 vlib/x/json2/decode_sumtype.v              | 12 ++++++++-
 vlib/x/json2/tests/decode_any_alias_test.v | 29 ++++++++++++++++++++++
 2 files changed, 40 insertions(+), 1 deletion(-)
 create mode 100644 vlib/x/json2/tests/decode_any_alias_test.v

diff --git a/vlib/x/json2/decode_sumtype.v b/vlib/x/json2/decode_sumtype.v
index 3533b2af3..fd624e333 100644
--- a/vlib/x/json2/decode_sumtype.v
+++ b/vlib/x/json2/decode_sumtype.v
@@ -329,7 +329,17 @@ fn (mut decoder Decoder) init_sumtype_by_value_kind[T](mut val T, value_info Val
 
 fn (mut decoder Decoder) decode_sumtype[T](mut val T) ! {
 	$if T is $alias {
-		decoder.decode_error('Type aliased sumtypes not supported.')!
+		$if T.unaliased_typ is Any {
+			mut unaliased_val := Any{}
+			value_info := decoder.current_node.value
+
+			decoder.init_sumtype_by_value_kind(mut unaliased_val, value_info)!
+
+			unaliased_val = decoder.get_decoded_sumtype_workaround(unaliased_val)!
+			val = T(unaliased_val)
+		} $else {
+			decoder.decode_error('Type aliased sumtypes not supported.')!
+		}
 	} $else {
 		value_info := decoder.current_node.value
 
diff --git a/vlib/x/json2/tests/decode_any_alias_test.v b/vlib/x/json2/tests/decode_any_alias_test.v
new file mode 100644
index 000000000..3301bce40
--- /dev/null
+++ b/vlib/x/json2/tests/decode_any_alias_test.v
@@ -0,0 +1,29 @@
+import x.json2 as json
+
+type Issue24127Any = json.Any
+type Issue24127Map = map[string]Issue24127Any
+
+const issue_24127_json_inputs = [
+	'{}',
+	'{"a":"b"}',
+	'{"a":1}',
+	'{"a":3.14}',
+	'{"a":{"b":"c"}}',
+	'{"a":true}',
+]
+
+fn test_decode_alias_of_any_sumtype() {
+	for input in issue_24127_json_inputs {
+		direct := json.decode[json.Any](input)!
+		aliased := json.decode[Issue24127Any](input)!
+		assert json.encode(direct) == json.encode(aliased)
+	}
+}
+
+fn test_decode_map_with_any_alias_value() {
+	for input in issue_24127_json_inputs {
+		direct := json.decode[map[string]json.Any](input)!
+		aliased := json.decode[Issue24127Map](input)!
+		assert json.encode(direct) == json.encode(aliased)
+	}
+}
-- 
2.39.5