Macros_Test_1.scala:2: error: macro implementation has wrong shape:
 required: (c: scala.reflect.macros.Context): c.Expr[Any]
 found   : (c: scala.reflect.macros.Context)(implicit evidence$2: Numeric[U]): c.universe.Literal
macro implementations cannot have implicit parameters other than WeakTypeTag evidences
  def foo[U] = macro Impls.foo[U]
                           ^
one error found