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