Impls_Macros_1.scala:8: error: macro implementation has incompatible shape:
 required: (c: scala.reflect.macros.blackbox.Context)(x: c.Expr[Int]): c.Expr[Nothing]
 or      : (c: scala.reflect.macros.blackbox.Context)(x: c.Tree): c.Tree
 found   : (c: scala.reflect.macros.blackbox.Context)(x: Int): Nothing
type mismatch for parameter x: c.Expr[Int] does not conform to Int
  def foo(x: Int) = macro Impls.foo
                                ^
one error found