# File lib/sass/script/tree/map_literal.rb, line 50 def _perform(environment) keys = Set.new map = Sass::Script::Value::Map.new(Sass::Util.to_hash(pairs.map do |(k, v)| k, v = k.perform(environment), v.perform(environment) if keys.include?(k) raise Sass::SyntaxError.new("Duplicate key #{k.inspect} in map #{to_sass}.") end keys << k [k, v] end)) map.options = options map end