diff --git a/v2/build/generators.jam b/v2/build/generators.jam
index 1887302a5..1da22d6f3 100644
--- a/v2/build/generators.jam
+++ b/v2/build/generators.jam
@@ -755,7 +755,7 @@ local rule viable-source-types-real ( target-type )
         }
     }
 
-    return [ sequence.unique $(result) ] ;
+    return $(result) ;
 }