lint: enable deadcode and varcheck

[ferhatelmas]

related to #292

didn't enable tests: true since they are included by default

[codecov-io]

Codecov Report

Merging #318 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #318   +/-   ##
=======================================
  Coverage   55.72%   55.72%           
=======================================
  Files          19       19           
  Lines         926      926           
=======================================
  Hits          516      516           
  Misses        358      358           
  Partials       52       52

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[ahmetb]

Feel free to say tests:true if it doesn’t hurt. I definitely want to make sure the linters work on tests.

Also what do either of these linters do? Can you briefly explain?

[corneliusweig]

https://golangci.com/product#linters says

varcheck: Finds unused global variables and constants.
deadcode: Finds unused code.

More info here: https://github.com/remyoudompheng/go-misc/tree/master/deadcode
and https://gitlab.com/opennota/check

[corneliusweig]

So I just checked, and also deadcode won't report functions which are no longer used by production code, but called by some test code 😭

[ahmetb]

Yeah it's not ideal, but it's better than untested/unrefereced methods laying around I guess.

[corneliusweig]

True, true. So let's get this merged then
/lgtm
/approve

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[APPROVALNOTIFIER] This PR is APPROVED

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