Description
2.11:
scala> { implicit def foo(a: Int)(b: Int, c: Int): String = "" + a + b; implicitly[Int => (Int, Int) => String].apply(1).apply(2, 3) }
warning: there was one feature warning; re-run with -feature for details
res0: String = 12
2.12
scala> { implicit def foo(a: Int)(b: Int, c: Int): String = "" + a + b; implicitly[Int => (Int, Int) => String].apply(1).apply(2, 3) }
<console>:12: error: No implicit view available from Int => (Int, Int) => String.
{ implicit def foo(a: Int)(b: Int, c: Int): String = "" + a + b; implicitly[Int => (Int, Int) => String].apply(1).apply(2, 3) }
^
Regressed with the pre-calculation of ptFunctionArity in scala/scala#5875, in which I failed to account for the recursion in checkCompatibility.