Structural.scala

$ scala -language:_
Welcome to Scala 2.11.8 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_45).
Type in expressions for evaluation. Or try :help.

scala> import reflect.macros.whitebox.Context
import reflect.macros.whitebox.Context

scala> def idImpl(c: Context)(t: c.Tree): c.Tree = t
idImpl: (c: scala.reflect.macros.whitebox.Context)(t: c.Tree)c.Tree

scala> class C { def id(t: Int): Int = macro idImpl }
defined class C

scala> val c = new C
c: C = C@564718df

scala> val test = c: { def id(t: Int): Int }
test: AnyRef{def id(t: Int): Int} = C@564718df

scala> test.id(3)
java.lang.NoSuchMethodException: C.id(int)
  at java.lang.Class.getMethod(Class.java:1786)
  at .reflMethod$Method1(<console>:17)
  ... 32 elided