Dissecting https://github.com/ktoso/scala-macro-method-alias

entry_point.scala

import language.experimental.macros // enable the macros language feature

import reflect.macros._

object Alias {
  def aliasFor[P1, P2, T](delegate: (P1, P2) => T): T = macro alias_impl[T]

  // ...
}

macro_impl.scala

def alias_impl[T](c: Context)(delegate: c.Expr[Any]): c.Expr[T] = {
    import c._

    val tree = delegate.tree.children match {
      case expr :: Nil =>

        val methodName = extractDelegateMethodName(c)

        val params = extractDelegatorParams(c).mkString(", ")

        parse(s"""$methodName($params)""") // : c.Tree

      case _ =>
        c.abort(c.enclosingPosition, "alias macro should only be used on single method delegation")
    }

    c.Expr(tree)
  }

method.scala

private def extractDelegateMethodName(c: Context)(children: List[c.universe.Tree]): c.universe.Tree =
  children
    .map(a => a.children)
    .flatten
    .filter(_.isTerm) // PS: yeap I know this is getting ugly/long
    .filterNot(a => a.isEmpty && a.toString == "aliasFor") // exclude the macro name
    .head // first tree inside our macro
    .children.head // the thing inside is partially applied - it should be just one method

start.scala

import pl.project13.scala.macros.Alias.aliasFor

def !!(a: String, b: Int) = aliasFor { manyParams _ }