# File lib/sass/tree/visitors/perform.rb, line 274
  def visit_directive(node)
    if node.value['#{']
      if node.value =~ /^@import (?!url\()/
        Sass::Util.sass_warn "DEPRECATION WARNING on line \#{node.line}\#{\" of \#{node.filename}\" if node.filename}:\n@import directives using \\\#{} interpolation will need to use url() in Sass 3.2.\nFor example:\n\n  @import url(\"http://\\\#{$url}/style.css\");\n"
      end
      node.value = run_interp(Sass::Engine.parse_interp(node.value, node.line, 0, node.options))
    end
    yield
    node
  end