Adding limit to a UNION SQL outputs incorrect sql in "tsql" dialect

[aman-wisdom]

Description
The issue exists in the latest version of sqlglot 26.6.0. When applying limit operation on a Union node and converting to T-SQL, we get an expression which is invalid in T-SQL.

Fully reproducible code snippet

>>> parse_one("select count(*) from a union select count(*) from b", dialect="tsql").limit(5).sql(dialect="tsql")
'SELECT TOP 5 * FROM (SELECT COUNT(*) FROM a UNION SELECT COUNT(*) FROM b) AS _l_0'

While this looks correct, it throws syntax error as shown in the image below. Note that the union query works as a standalone but not when placed within parantheses. (See error message at the bottom of the image.)

Official Documentation
Couldn't find the official documentation explaining this situation, but it should be reproducible anywhere I think.

[georgesittas]

This is unrelated to the limit, the query you get back should work as long as the counts are aliased:

1> WITH a AS (SELECT 1 AS id), b AS (SELECT 2 AS id) SELECT TOP 5 * FROM (SELECT COUNT(*) AS col FROM a UNION SELECT COUNT(*) AS col FROM b) AS _l_0
2> GO
col        
-----------
          1

(1 rows affected)