Compiler does not reevaluate apply's implicit each time apply is called, when the applications are in the same statement.

The compiler would be correct if test were a function, and the implicit was defined at the function definition site. In that case the implicit is only supposed to be evaluated in the first application to a function, where the type parameters are then fully determined.

However, this is not the case below, because the implicit is declared not for the function test but for the application function apply, and thus the type parameter A should be determined separately for each invocation of apply. It is proven as shown below by the fact that invoking apply with separate statements or even explicitly calling .apply more than once in the same statement does compile as expected.

The motivating use case is for a workaround to a use case that applies to bug SI-5550.

class Test {
  def apply[A](v: A)(implicit d: A <:< Any) = this
}
val test = new Test

scala> test(1)
res0: Test = Test@a541e5

scala> test("")
res1: Test = Test@a541e5

scala> test(1).apply("")
res2: Test = Test@105f21c

scala> test(1)("")
error: type mismatch;
 found   : java.lang.String("")
 required: <:<[Int,Any]
       test(1)("")
               ^