code: func (l *Loader) ImportSources(sources map[string][]byte) {
  	p := l.Parser()
  	for name, src := range sources {
  		p.ForceFileSource(name, src)
  	}
  }
docs: // ImportSources writes into the receiver's source code the given source
  // code buffers.
  //
  // This is useful in the situation where an ancillary loader is created for
  // some reason (e.g. loading config from a plan file) but the cached source
  // code from that loader must be imported into the "main" loader in order
  // to return source code snapshots in diagnostic messages.
  //
  //     loader.ImportSources(otherLoader.Sources())