[BUG] Incorrect syntax error in GROUP BY clause

[hiroyuki0415]

SELECT   s.uniquename,
         MAX(IIF (s.uniquename = 'xxx', COALESCE (sc.componenttype, -1), NULL)) AS [aggregation]
FROM     solution AS s
         INNER JOIN
         solutioncomponent AS sc
         ON s.solutionid = sc.solutionid
GROUP BY s.uniquename;

When I run this SQL I get the below error:

Msg 102, Level 15, State 1, Line 1
Incorrect syntax near 'COALESCE (sc.componenttype, -1)'.

Msg 102, Level 15, State 1, Line 1
Incorrect syntax near 'COALESCE (sc.componenttype, -1)'.