prealloc: false positive

[carnott-snap]

1. Version of golangci-lint: golangci-lint --version (or git commit if you don't use binary distribution)

golangci-lint has version v1.17.1 built from (unknown, mod sum: "h1:lc8Hf9GPCjIr0hg3S/xhvFT1+Hydass8F1xchr8jkME=") on (unknown)

2. Config file: cat .golangci.toml

[linters]
disable-all = true
enable = ["prealloc"]

3. Go environment: go version && go env

go version go1.12.7 linux/amd64

GOARCH="amd64"
GOBIN=""
GOCACHE="/home/user/.cache/go-build"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/user/go"
GOPROXY=""
GORACE=""
GOROOT="/home/user/.local/share/umake/go/go-lang"
GOTMPDIR=""
GOTOOLDIR="/home/user/.local/share/umake/go/go-lang/pkg/tool/linux_amd64"
GCCGO="gccgo"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/tmp/test/go.mod"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build952158134=/tmp/go-build -gno-record-gcc-switches"

4. Verbose output of running: golangci-lint run -v

INFO [config_reader] Config search paths: [./ /tmp/test /tmp /] 
INFO [config_reader] Used config file .golangci.toml 
INFO [lintersdb] Active 1 linters: [prealloc]     
INFO [loader] Go packages loading at mode load files took 39.075415ms 
INFO [runner] worker.1 took 2.247µs               
INFO [runner] worker.3 took 5.257µs               
INFO [runner] worker.4 took 16.694µs              
INFO [runner] worker.2 took 95.789µs with stages: prealloc: 56.232µs 
INFO [runner] Workers idle times: #1: 41.617µs, #3: 21.566µs, #4: 9.983µs 
INFO [runner] processing took 266.368µs with stages: exclude: 90.072µs, identifier_marker: 77.485µs, source_code: 36.31µs, skip_dirs: 14.474µs, nolint: 11.319µs, autogenerated_exclude: 11.138µs, cgo: 8.666µs, path_prettifier: 7.254µs, uniq_by_line: 2.226µs, max_same_issues: 1.884µs, path_shortener: 1.619µs, max_from_linter: 1.141µs, filename_unadjuster: 990ns, max_per_file_from_linter: 884ns, diff: 437ns, skip_files: 277ns, exclude-rules: 192ns 
main.go:4:2: Consider preallocating `a` (prealloc)
        var a []int
        ^
INFO File cache stats: 1 entries of total size 135B 
INFO Memory: 2 samples, avg is 68.9MB, max is 68.9MB 
INFO Execution took 78.8856ms                     

5. This issue was also reported upstream: line of sight loops trick prealloc alexkohler/prealloc#16

var a []int
for i := range []struct{}{{}, {}, {}} {
        if i < 1 {
              continue
        } 
        a = append(a, i)
}

[jirfag]

Thank you, please reopen when upstream will be fixed to update it