Run all linters per package. It allows unloading package data when it's
processed. It dramatically reduces memory (and CPU because of GC) usage.
Relates: #337
* update staticcheck
Don't fork staticcheck: use the upstream version.
Remove unneeded SSA loading.
* Cache go/analysis facts
Don't load unneeded packages for go/analysis.
Repeated run of go/analysis linters now 10x faster
(2s vs 20s on this repo) than before.
Don't perform extra go env calls in go/packages.
Load only needed go env vars in golangci-lint.
Stay in sync by enabled analyzers in go vet: remove nilness and
atomicalign analyzers, add errorsas analyzer.
Don't build SSA for govet.
Standalone govet runs 25% faster than before. All runs can be 5-10% faster
than before.
Relates: #208
Also do following improvements:
- show proper sublinter name for megacheck sublinters
- refactor and make more simple and robust megacheck
merging/optimizing
- improve handling of unknown linter names in //nolint directives
- minimize diff of our megacheck version from the upstream,
https://github.com/golang/go/issues/29612 blocks usage of the upstream
version
- support the new `stylecheck` linter
- improve tests coverage for megacheck and nolint related cases
- update and use upstream versions of unparam and interfacer instead of forked
ones
- don't use golangci/tools repo anymore
- fix newly found issues after updating linters
Also should be noted that megacheck works much faster and consumes less
memory in the newest release, therefore golangci-lint works noticeably
faster and consumes less memory for large repos.
Relates: #314
