Error constants in Golang

Fri, 24 Apr 2026 11:00:31 +0200

Error constants in Golang

Something that’s been bugging me for years is the fact that you can’t just declare errors as constants in Golang using just the standard library. I finally got annyoed enough by it to do some googling on Bing, and found this great solution by Jonathan Hall on boldlygo.tech from last year:

type errString string

func (e errString) Error() string {
  return string(e)
}

const ErrTooManyFrogs = errString("too many frogs")

This is a great idea, and a great start, but I wanted to be able to just drop-in a package in place of the standard library’s "errors" package, so came up with this:

Thoughts of a grumpy developer

Error constants in Golang

Error constants in Golang