Added neg test

(scalac and dotty both produce an error here)

Author: odersky

tests/neg/i739.scala

@@ -0,0 +1,7 @@
+class Foo[A, B]
+class Test {
+  implicit val f: Foo[Int, String] = ???
+  def t[A, B >: A](a: A)(implicit f: Foo[A, B]) = ???
+  t(1) // error
+}
+