x/tools/gopls: add codelens for references to symbols

[sanket-bhalerao]

Issue Type: Feature Request

it would be nice to see if a function is referenced in the code or not.
click on the codelens and see all the places the variable, function being referenced.

variable:

functions:

Extension version: 2020.8.1301
VS Code version: Code - Insiders 1.49.0-insider (bd08768fd310d34cdd4423a53e5f3ca77340fea5, 2020-08-14T05:56:40.601Z)
OS version: Windows_NT x64 10.0.18363

[stamblerre]

I believe that this feature is supported in GOPATH mode, but is not yet available via the language server. I have been hesitant to add it, since users should just be able to call "Find References" on a symbol to get this information. I would be curious to hear input from others before we move forward with this.

[sanket-bhalerao]

@stamblerre, i tried following for the GOPATH mode.

• set GOPATH to current working directory
• install all the tools required for the extension
• my settings for go are
  

i still dont see the codelens.
am i missing something?

[hyangah]

The codelens is off by default, so you will need to turn it on explicitly.

"go.enableCodeLens": {
        "references": true,
    }

But, if you are using the language server, why not use the Find References feature which is faster and doesn't add much visual noise to the code.

[sanket-bhalerao]

@hyangah , thanks for the help
as to why not use find reference, i work mainly with angular and now just habituated with the codelens. i feel more comfortable with it i guess

[hyangah]

@sanket-bhalerao Is your goal to simply check whether the variable or function is used or not (boolean decision), or you use it to really find all the locations they are used? For former, I think we can do better with color or other visualization than with codelens. For latter, maybe we should discuss more.

[sanket-bhalerao]

@hyangah for variables its the boolean decision (as golang shows unused var as errors this part is already covered)
for functions and methods I use it for find if it is referenced at alss and all the places its used.

[hyangah]

@sanket-bhalerao Thanks! I will transfer this to gopls issue tracker.

[stamblerre]

Thanks for the feature request, @sanket-bhalerao. I'd like to hear from others about the benefits of this feature. Currently, my preference would be to add the 'unused' checks from staticcheck (#36602), which might make this feature a little redundant.

[TheSecEng]

references is a quick insight into how many times a function is being called an generally would allow the end click to create a view into where the functions / etc are being used for quick looks. I think this is much more valuable than what is being shown here. And completely different from staticcheck. Just look at elm language server for instance

[stamblerre]

references is a quick insight into how many times a function is being called an generally would allow the end click to create a view into where the functions / etc are being used for quick looks. I think this is much more valuable than what is being shown here. And completely different from staticcheck. Just look at elm language server for instance

This feature is already available by right-clicking an identifier and selecting "Find all references". The code lens would make it easy to tell if a symbol is referenced, which is typically used to see if it is used anywhere in the workspace--much like the staticcheck 'unused' check.

[TheSecEng]

I guess a workaround to get this feature would just have the client implementation make the request automatically rather than having to click and request them. 🤷‍♂️ Seems like it may be more of a personal preference thing at that point ?

[stamblerre]

I think we would be open to this feature being added in gopls, but it would have to be off by default, because it would be expensive to constantly call "find references" on every symbol in a given file. Still, we will not prioritize work on this, so if a community member would like to pick this up and send a CL, please follow up here.