t8764.scala: productElement typing

[DarkDimius]

[info] % dotc t8764.scala
[info]
[info] compiling /Users/dark/workspace/dotty/tests/partest-generated/run/t8764.scala
[info] options: -pagewidth 160 -Yno-deep-subtypes -Yno-double-bindings -Ycheck:tailrec,resolveSuper,mixin,restoreScopes -d ./tests/partest-generated/run/t8764-run.obj
[info] /Users/dark/workspace/dotty/tests/partest-generated/run/t8764.scala:12: error: type mismatch:
[info]  found   : Any
[info]  required: Int
[info] val i: Int = a.productElement(0)
[info]                              ^
[info] /Users/dark/workspace/dotty/tests/partest-generated/run/t8764.scala:19: error: type mismatch:
[info]  found   : Any
[info]  required: AnyVal
[info] Note that implicit conversions cannot be applied because they are ambiguous;
[info]  both method any2stringadd in object Predef$ and method ArrowAssoc in object Predef$ convert from Any to AnyVal
[info] val j: AnyVal = b.productElement(0)
[info]                                 ^
[info] two errors found