t8463.scala:5: error: type mismatch;
 found   : Long
 required: ?T[Long]
Note that implicit conversions are not applicable because they are ambiguous:
 both method longWrapper in class LowPriorityImplicits of type (x: Long)scala.runtime.RichLong
 and method ArrowAssoc in object Predef of type [A](self: A)ArrowAssoc[A]
 are possible conversion functions from Long to ?T[Long]
  insertCell(Foo(5))
            ^
t8463.scala:5: error: no type parameters for method apply: (activity: T[Long])Test.Foo[T] in object Foo exist so that it can be applied to arguments (Long)
 --- because ---
argument expression's type is not compatible with formal parameter type;
 found   : Long
 required: ?T[Long]
  insertCell(Foo(5))
             ^
t8463.scala:5: error: type mismatch;
 found   : Long(5L)
 required: T[Long]
  insertCell(Foo(5))
                 ^
t8463.scala:5: error: type mismatch;
 found   : Test.Foo[T]
 required: Test.Foo[Test.Cell]
  insertCell(Foo(5))
                ^
four errors found