code: func (f *file) lintContextKeyTypes() {
  	f.walk(func(node ast.Node) bool {
  		switch node := node.(type) {
  		case *ast.CallExpr:
  			f.checkContextKeyType(node)
  		}
  
  		return true
  	})
  }
docs: // lintContextKeyTypes checks for call expressions to context.WithValue with
  // basic types used for the key argument.
  // See: https://golang.org/issue/17293