diff --git a/src/hb-ot-cff-common.hh b/src/hb-ot-cff-common.hh
index ddec517a1..55ae10efe 100644
--- a/src/hb-ot-cff-common.hh
+++ b/src/hb-ot-cff-common.hh
@@ -655,9 +655,9 @@ struct FDSelect {
     TRACE_SANITIZE (this);
 
     return_trace (likely (c->check_struct (this) && (format == 0 || format == 3) &&
-			  (format == 0)?
+			  ((format == 0)?
 			  u.format0.sanitize (c, fdcount):
-			  u.format3.sanitize (c, fdcount)));
+			  u.format3.sanitize (c, fdcount))));
   }
 
   bool serialize (hb_serialize_context_t *c, const FDSelect &src, unsigned int num_glyphs)