Trivial type safe heterogenous map using only dependent method types, singleton-typed String literal keys and implicits.

gistfile1.scala

scala> trait Assoc[K] { type V ; val value: V }
defined trait Assoc

scala> def mkAssoc[V0](k: String, v: V0): Assoc[k.type] { type V = V0 } =
     |   new Assoc[k.type] { type V = V0 ; val value = v }
mkAssoc: [V0](k: String, v: V0)Assoc[k.type]{type V = V0}

scala> implicit def nameAssoc = mkAssoc("Name", "Mary")
nameAssoc: Assoc[String("Name")]{type V = String}

scala> implicit def ageAssoc = mkAssoc("Age", 23)
ageAssoc: Assoc[String("Age")]{type V = Int}

scala> def lookup(k: String)(implicit assoc: Assoc[k.type]): assoc.V = assoc.value
lookup: (k: String)(implicit assoc: Assoc[k.type])assoc.V

scala> lookup("Name")
res0: String = Mary

scala> lookup("Age")
res1: Int = 23