Add more tests

Also test right-associative combinations and combinations with Null

Author: odersky

tests/pos/i10217.scala

@@ -24,4 +24,9 @@ trait W
 
 class Foo[T]
 
-val f = Foo[A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U]
+val f1 = Foo[A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U]
+val f2 = Foo[A | (B | (C | (D | (E | (F | (G | (H | (I | (J | (K | (L | (M | (N | (O | (P | (Q | (R | (S | (T | U)))))))))))))))))))]
+val f3 = Foo[Null | Null | Null | Null | Null | Null | Null | Null | Null | Null | Null | Null | Null | Null | Null | Null | Null | Null | Null | Null | A]
+val f4 = Foo[A | Null | Null | Null | Null | Null | Null | Null | Null | Null | Null | Null | Null | Null | Null | Null | Null | Null | Null | Null | Null]
+val f5 = Foo[Null | (Null | (Null | (Null | (Null | (Null | (Null | (Null | (Null | (Null | (Null | (Null | (Null | (Null | (Null | (Null | (Null | (Null | (Null | (Null | A)))))))))))))))))))]
+val f6 = Foo[A | (Null | (Null | (Null | (Null | (Null | (Null | (Null | (Null | (Null | (Null | (Null | (Null | (Null | (Null | (Null | (Null | (Null | (Null | Null))))))))))))))))))]