all: various very small cleanups from gopls and staticcheck

I had been accumulating tiny tweaks and cleanups that were too small
to require a commit or review of their own.

* doTasks has had an unused parameter for a long time.
* publishRegistryResolverShim has an unused field.
* writeIndex did not actually check an error from os.WriteFile.
* extractFeatures can prepare the right slice capacities ahead of time.
* A few places can avoid the type parameter in generic func calls;
  note that type inference got much better with Go 1.21.
* zeroReader.Read can make use of the new clear builtin in Go 1.21

Signed-off-by: Daniel Martí <mvdan@mvdan.cc>
Change-Id: I4206073007191c28782acebe926c00ce3c3498db
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1194842
Unity-Result: CUE porcuepine <cue.porcuepine@gmail.com>
Reviewed-by: Noam Dolovich <noam.tzvi.dolovich@gmail.com>
TryBot-Result: CUEcueckoo <cueckoo@cuelang.org>
Reviewed-by: Roger Peppe <rogpeppe@gmail.com>

cmd/cue/cmd/custom.go

@@ -141,15 +141,15 @@ func customCommand(c *Command, typ, name string, tools *cue.Instance) (*cobra.Co
 			// - parse flags and env vars
 			// - constrain current config with config section
 
-			return doTasks(cmd, typ, name, tools)
+			return doTasks(cmd, name, tools)
 		}),
 	}
 
 	// TODO: implement var/flag handling.
 	return sub, nil
 }
 
-func doTasks(cmd *Command, typ, command string, root *cue.Instance) error {
+func doTasks(cmd *Command, command string, root *cue.Instance) error {
 	cfg := &flow.Config{
 		Root:           cue.MakePath(cue.Str(commandSection), cue.Str(command)),
 		InferTasks:     true,

cmd/cue/cmd/modpublish.go

@@ -162,7 +162,7 @@ func runModUpload(cmd *Command, args []string) error {
 		if err != nil {
 			return err
 		}
-		if err := modzip.Create[string](zf, mv, files, osFileIO{
+		if err := modzip.Create(zf, mv, files, osFileIO{
 			modRoot: modRoot,
 		}); err != nil {
 			return err
@@ -253,7 +253,6 @@ func (fio osFileIO) absPath(f string) string {
 // module's zip file.
 type publishRegistryResolverShim struct {
 	resolver    *modconfig.Resolver
-	registry    ociregistry.Interface
 	dryRun      bool
 	recordFiles bool
 	outDir      string
@@ -320,7 +319,7 @@ func (r *publishRegistryResolverShim) writeIndex() error {
 		return err
 	}
 	data = append(data, '\n')
-	if os.WriteFile(filepath.Join(r.outDir, "index.json"), data, 0o666); err != nil {
+	if err := os.WriteFile(filepath.Join(r.outDir, "index.json"), data, 0o666); err != nil {
 		return err
 	}
 	return nil

internal/core/export/toposort.go

@@ -52,9 +52,10 @@ func VertexFeatures(c *adt.OpContext, v *adt.Vertex) []adt.Feature {
 }
 
 func extractFeatures(in []*adt.StructInfo) (a [][]adt.Feature) {
+	a = make([][]adt.Feature, 0, len(in))
 	for _, s := range in {
-		sorted := []adt.Feature{}
-		for _, e := range s.StructLit.Decls {
+		sorted := make([]adt.Feature, 0, len(s.Decls))
+		for _, e := range s.Decls {
 			switch x := e.(type) {
 			case *adt.Field:
 				sorted = append(sorted, x.Label)

mod/modzip/zip.go

@@ -374,7 +374,7 @@ func CheckDir(dir string) (CheckedFiles, error) {
 	if err != nil {
 		return CheckedFiles{}, err
 	}
-	cf, cfErr := CheckFiles[dirFile](files, dirFileIO{})
+	cf, cfErr := CheckFiles(files, dirFileIO{})
 	_ = cfErr // ignore this error; we'll generate our own after rewriting paths.
 
 	// Replace all paths with file system paths.
@@ -595,7 +595,7 @@ func CreateFromDir(w io.Writer, m module.Version, dir string) (err error) {
 		return err
 	}
 
-	return Create[dirFile](w, m, files, dirFileIO{})
+	return Create(w, m, files, dirFileIO{})
 }
 
 type dirFile struct {

mod/modzip/zip_test.go

@@ -179,9 +179,7 @@ func (fi fakeFileInfo) Sys() interface{}   { return nil }
 type zeroReader struct{}
 
 func (r zeroReader) Read(b []byte) (int, error) {
-	for i := range b {
-		b[i] = 0
-	}
+	clear(b)
 	return len(b), nil
 }