import scala.language.experimental.namedTuples object Test: type NT = NamedTuple.Concat[(hi: Int), (bla: String)] def foo(x: NT) = x.hi // error val y: (hi: Int, bla: String) = x y.hi // ok

[error] ./try/nt.scala:6:5 [error] Found: (x$proxy1 : (x : Test.NT) & [error] $proxy1.NamedTuple[ [error] Tuple.Concat[ [error] NamedTupleDecomposition.Names[ [error] $proxy1.NamedTuple[Tuple1[("hi" : String)], Tuple1[Int]]], [error] NamedTupleDecomposition.Names[ [error] $proxy1.NamedTuple[Tuple1[("bla" : String)], Tuple1[String]]] [error] ], [error] Tuple.Concat[ [error] NamedTupleDecomposition.DropNames[ [error] $proxy1.NamedTuple[Tuple1[("hi" : String)], Tuple1[Int]]], [error] NamedTupleDecomposition.DropNames[ [error] $proxy1.NamedTuple[Tuple1[("bla" : String)], Tuple1[String]]] [error] ] [error] ] [error] ) [error] Required: (Int, String) [error] x.hi // error [error] ^

 val $proxy1: NamedTuple.type{ type AnyNamedTuple = Any; type NamedTuple[N <: Tuple,V <: Tuple] = V } = NamedTuple.$asInstanceOf[ NamedTuple.type{ type AnyNamedTuple = Any; type NamedTuple[N <: Tuple,V <: Tuple] = V } ] val NamedTuple$_this: ($proxy1 : NamedTuple.type{ type AnyNamedTuple = Any; type NamedTuple[N <: Tuple,V <: Tuple] = V } ) = $proxy1 { val $scrutinee1: <error unspecified error> = NamedTuple$_this.toTuple[(("hi" : String), ("bla" : String)), (Int, String)](x$proxy1) val tup: <error unspecified error> = $scrutinee1 tup.apply[(Int, String) & NonEmptyTuple](0).asInstanceOf[ Tuple.Elem[(Int, String), 0.type]]