code: func (p *Package) objectOf(id *ast.Ident) types.Object {
  	if o := p.info.ObjectOf(id); o != nil {
  		return o
  	}
  	panic(fmt.Sprintf("no types.Object for ast.Ident %s @ %s",
  		id.Name, p.Prog.Fset.Position(id.Pos())))
  }
docs: // Like ObjectOf, but panics instead of returning nil.
  // Only valid during p's create and build phases.