code: func (v *Context) Error(err error) {
  	ctx := ""
  	if v.file != "" {
  		ctx = fmt.Sprintf("in %q", v.file)
  	} else {
  		ctx = "in <unspecified file>"
  	}
  	if len(v.element) != 0 {
  		ctx += " (" + strings.Join(v.element, " / ") + ")"
  	}
  	// Make the file and the logical path also usable through error inspection.
  	err = errors.Annotate(err, "%s", ctx).Tag(fileTag.With(v.file), elementTag.With(v.element)).Err()
  	v.errors = append(v.errors, err)
  }
docs: // Error records the given error as a validation error.