gouse

Toggle ‘declared and not used’ errors in Go by using idiomatic _ = notUsedVar and leaving a TODO comment.

Installation

go install github.com/looshch/gouse@latest

Caution

Non-stable (archived) Go versions require older gouse version.

Go version	gouse version
1.21.0+	1.3.0+
1.18–1.20.14	1.2.3

Usage

By default, gouse accepts code from stdin or from a file provided as a path argument and writes the toggled version to stdout. ‘-w’ flag writes the result back to the file. If multiple paths provided, ‘-w’ flag is required.

Examples

$ gouse
...input...
notUsed = true
...input...

...output...
notUsed = true; _ = notUsed /* TODO: gouse */
...output...

$ gouse main.go
...
notUsed = true; _ = notUsed /* TODO: gouse */
...

$ gouse -w main.go io.go core.go
$ cat main.go io.go core.go
...
notUsedFromMain = true; _ = notUsedFromMain /* TODO: gouse */
...
notUsedFromIo = true; _ = notUsedFromIo /* TODO: gouse */
...
notUsedFromCore = true; _ = notUsedFromCore /* TODO: gouse */
...

How it works

First it tries to remove previously created fake usages. If there is nothing to remove, it tries to build an input and checks the build stdout for ‘declared and not used’ errors. If there is any, it creates fake usages for unused variables from the errors.

Integrations

• Vim: just bind <cmd> w <bar> silent !gouse -w %<cr> to some mapping.
• Visual Studio Code plugin.

Credits

Inspired by Nikita Rabaev’s idea.