$ semgrep --quiet --lang=go --pattern='$PKG.IndexFunc(...) >= 0'

Findings:

  src/archive/tar/reader.go
        395┆ if bytes.IndexFunc(tr.blk[:], notASCII) >= 0 {


  src/testing/benchmark.go
        353┆ if strings.IndexFunc(unit, unicode.IsSpace) >= 0 {

 $ semgrep --quiet --lang=go --pattern='$PKG.IndexFunc(...) < 0'

Findings:

  src/mime/grammar.go
         31┆ return strings.IndexFunc(s, isNotTokenChar) < 0


  src/net/http/cookie.go
        465┆ return strings.IndexFunc(raw, isNotToken) < 0


  src/text/template/funcs.go
        725┆ if strings.IndexFunc(s, jsIsSpecial) < 0 {

 $ semgrep --quiet --lang=go --pattern='$PKG.IndexFunc(...) == -1'

Findings:

  src/net/http/request.go
        831┆ return len(method) > 0 && strings.IndexFunc(method, isNotToken) == -1

 $ semgrep --quiet --lang=go --pattern='$PKG.IndexFunc(...) != -1'

Findings:

  staging/src/k8s.io/client-go/rest/request.go
       1068┆ if bytes.IndexFunc(body, func(r rune) bool {
       1069┆    return r < 0x0a
       1070┆ }) != -1 {


  staging/src/k8s.io/kubectl/pkg/describe/describe.go
        349┆ if strings.IndexFunc(field, func(r rune) bool {
        350┆    return !unicode.IsLetter(r) && r != '-'
        351┆ }) != -1 {