return true, nil
			}

		case underscore:
			if len(s) == 0 {
				text, ok = dropRune(text)
				if !ok {
					return false, nil
				}
				continue
			}

			text, ok = matcher(text, string(s), hasLeadingPercent)
			if !ok {
				return false, nil
			}
			hasLeadingPercent = false

			text, ok = dropRune(text)
			if !ok {
				return false, nil
			}
			s = []rune{}

		case escape:

	}{
		{"", "", false},
		{"a", "", true},
		{"ab", "b", true},
		{"தமிழ்", "மிழ்", true},
	}

	for i, tc := range dropCases {
		res, ok := dropRune(tc.input)
		if res != tc.resultExpected || ok != tc.matchExpected {
			t.Errorf("DropRune Case %d failed", i)
		}
	}

	matcherCases := []struct {
		iText, iPat        string
		iHasLeadingPercent bool
		resultExpected     string
		matchExpected      bool

go work edit -go 1.18
cmp go.work go.work.want_go_118

go work edit -dropuse m
cmp go.work go.work.want_dropuse_m

go work edit -replace=x.1@v1.3.0=y.1@v1.4.0 -replace='x.1@v1.4.0 = ../z'
cmp go.work go.work.want_add_replaces

go work edit -use n -use ../a -use /b -use c -use c
cmp go.work go.work.want_multiuse

go work edit -dropuse /b -dropuse n
cmp go.work go.work.want_multidropuse

go work edit -dropreplace='x.1@v1.4.0'

			base.Fatalf("go: -use=%s: %v", arg, err)
		}
	})
}

// flagEditworkDropUse implements the -dropuse flag.
func flagEditworkDropUse(arg string) {
	workedits = append(workedits, func(f *modfile.WorkFile) {
		if err := f.DropUse(modload.ToDirectoryPath(arg)); err != nil {
			base.Fatalf("go: -dropdirectory=%s: %v", arg, err)
		}
	})
}

			if dir == keepDir { // (note that dir is always non-empty)
				nKept++
			} else {
				wf.DropUse(dir)
			}
		}
		if keepDir != "" && nKept != 1 {
			// If we kept more than one copy, delete them all.
			// We'll recreate a unique copy with AddUse.
			if nKept > 1 {
				wf.DropUse(keepDir)
			}
			wf.AddUse(keepDir, "")
		}
	}

	"defer":           contentTypeUnsafe,
	"dir":             contentTypePlain,
	"dirname":         contentTypePlain,
	"disabled":        contentTypePlain,
	"draggable":       contentTypePlain,
	"dropzone":        contentTypePlain,
	"enctype":         contentTypeUnsafe,
	"for":             contentTypePlain,
	"form":            contentTypeUnsafe,
	"formaction":      contentTypeURL,
	"formenctype":     contentTypeUnsafe,

		}
	}

	// TODO(#45713): Add module path to comment.

	for diskPath, modulePath := range need {
		f.AddNewUse(diskPath, modulePath)
	}
	f.SortBlocks()
}

func (f *WorkFile) DropUse(path string) error {
	for _, d := range f.Use {
		if d.Path == path {
			d.Syntax.markRemoved()
			*d = Use{}
		}
	}
	return nil
}

	`)

	testCases := []struct {
		nfacctEnsured  bool
		tcpLiberal     bool
		dropRule       string
		nfAcctCounters map[string]bool
	}{
		{
			nfacctEnsured:  false,
			tcpLiberal:     false,
			nfAcctCounters: map[string]bool{},
			dropRule:       "-A KUBE-FORWARD -m conntrack --ctstate INVALID -j DROP",
		},
		{
			nfacctEnsured: true,

// replacing any existing godebug lines with the given key.
//
// The -dropgodebug=key flag drops any existing godebug lines
// with the given key.
//
// The -use=path and -dropuse=path flags
// add and drop a use directive from the go.work file's set of module directories.
//
// The -replace=old[@v]=new[@v] flag adds a replacement of the given