class Gem::Resolver::LockSet

def load_spec name, version, platform, source # :nodoc:
  dep = Gem::Dependency.new name, version
  found = @specs.find do |spec|
    dep.matches_spec? spec and spec.platform == platform
  end
  tuple = Gem::NameTuple.new found.name, found.version, found.platform
  found.source.fetch_spec tuple
end