go/format: Inconsistent rendering of *ast.BasicLit

[pjebs]

Go version

go version go1.24.0 darwin/amd64

Output of go env in your module/workspace:

Playground

What did you do?

See: https://go.dev/play/p/cF220dL8yUT

Sometimes I use *ast.BasicLit in my Code generators to write Go statements rather than properly breaking down the statement to the proper ast.* components. It's just easier this way and has never caused me any issues.

Until I noticed this very specific bug:

&ast.BasicLit{
	Kind:  token.INT,
	Value: "Error()",
}

gets rendered as:

error()

I understand this is not the proper way to parse and/or alter the syntax tree. This bug report is just regarding a weird inconsistency. Every other combination for Value: works properly.

What did you see happen?

Improper rendering.

What did you expect to see?

I expected to see: Error()

In the Go playground you can change the stmt to ANYTHING else and it will render properly:

https://go.dev/play/p/cF220dL8yUT
https://go.dev/play/p/FuxSXer6I4g

(WORK-AROUND: When I change it to token.STRING it works)

[seankhliao]

given it's invalid input, I don't think it's necessary to fix. That other things don't break when you pass it invalid input is coincidental, not a feature.

[pjebs]

I agree 100%. My thinking was that there may be something more sinister going on that could or would effect other legitimate things, given the specificity of the bug and the associated strangeness.