Added a test from @nvartolomei #6229

tests/queries/0_stateless/01263_type_conversion_nvartolomei.reference

+123
+123
+a
+a
+---
+a
+a

tests/queries/0_stateless/01263_type_conversion_nvartolomei.sql

+DROP TABLE IF EXISTS m;
+DROP TABLE IF EXISTS d;
+
+CREATE TABLE m
+(
+    `v` UInt8
+)
+ENGINE = MergeTree()
+PARTITION BY tuple()
+ORDER BY v;
+
+CREATE TABLE d
+(
+    `v` UInt16
+)
+ENGINE = Distributed('test_cluster_two_shards', currentDatabase(), m, rand());
+
+INSERT INTO m VALUES (123);
+SELECT * FROM d;
+
+
+DROP TABLE m;
+DROP TABLE d;
+
+
+CREATE TABLE m
+(
+    `v` Enum8('a' = 1, 'b' = 2)
+)
+ENGINE = MergeTree()
+PARTITION BY tuple()
+ORDER BY v;
+
+CREATE TABLE d
+(
+    `v` Enum8('a' = 1)
+)
+ENGINE = Distributed('test_cluster_two_shards', currentDatabase(), m, rand());
+
+INSERT INTO m VALUES ('a');
+SELECT * FROM d;
+
+SELECT '---';
+
+INSERT INTO m VALUES ('b');
+SELECT v FROM d ORDER BY v; -- { clientError 36 }
+
+
+DROP TABLE m;
+DROP TABLE d;