import scala.reflect.makro.{Context => Ctx} object Impls { def foo[U](c: Ctx)(x: c.Expr[U])(evidence: c.Expr[Numeric[U]]) = { import c.mirror._ val plusOne = Apply(Select(evidence.tree, newTermName("plus")), List(x.tree, Literal(Constant(1)))) val body = Apply(Select(Ident(definitions.PredefModule), newTermName("println")), List(plusOne)) Expr[Unit](body) } }