diff --git a/cmd/cue/cmd/add.go b/cmd/cue/cmd/add.go
index 68f101b..559b911 100644
--- a/cmd/cue/cmd/add.go
+++ b/cmd/cue/cmd/add.go
@@ -153,7 +153,7 @@
 		stdout := cmd.OutOrStdout()
 		for _, fi := range todo {
 			fmt.Fprintln(stdout, "---", fi.filename)
-			io.Copy(stdout, fi.contents)
+			_, _ = io.Copy(stdout, fi.contents)
 		}
 		return nil
 	}
@@ -291,7 +291,7 @@
 
 	if err = ioutil.WriteFile(fi.filename, b, 0644); err != nil {
 		// Just in case, attempt to restore original file.
-		fo.restore()
+		_ = fo.restore()
 		return originalFile{}, err
 	}
 
diff --git a/cmd/cue/cmd/common.go b/cmd/cue/cmd/common.go
index 992164d..0a8e36a 100644
--- a/cmd/cue/cmd/common.go
+++ b/cmd/cue/cmd/common.go
@@ -19,6 +19,7 @@
 	"io"
 	"os"
 	"strings"
+	"testing"
 
 	"cuelang.org/go/cue"
 	"cuelang.org/go/cue/build"
@@ -33,6 +34,12 @@
 
 var inTest = false
 
+func mustParseFlags(t *testing.T, cmd *cobra.Command, flags ...string) {
+	if err := cmd.ParseFlags(flags); err != nil {
+		t.Fatal(err)
+	}
+}
+
 func exitIfErr(cmd *cobra.Command, inst *cue.Instance, err error, fatal bool) {
 	exitOnErr(cmd, err, fatal)
 }
@@ -67,7 +74,7 @@
 	})
 
 	b := w.Bytes()
-	cmd.OutOrStderr().Write(b)
+	_, _ = cmd.OutOrStderr().Write(b)
 	if fatal {
 		exit()
 	}
diff --git a/cmd/cue/cmd/common_test.go b/cmd/cue/cmd/common_test.go
index 3399c63..50513cf 100644
--- a/cmd/cue/cmd/common_test.go
+++ b/cmd/cue/cmd/common_test.go
@@ -57,7 +57,7 @@
 
 	cfg := printConfig(t)
 
-	filepath.Walk(dir, func(path string, info os.FileInfo, err error) error {
+	_ = filepath.Walk(dir, func(path string, info os.FileInfo, err error) error {
 		t.Run(path, func(t *testing.T) {
 			if err != nil {
 				t.Fatal(err)
@@ -92,8 +92,7 @@
 						fmt.Fprintln(wOut, err)
 					}
 				}()
-				cmd.Execute()
-				return nil
+				return cmd.Execute()
 			})
 			g.Go(func() error {
 				bOut, err = ioutil.ReadAll(rOut)
@@ -105,7 +104,7 @@
 				t.Error(err)
 			}
 			if *update {
-				ioutil.WriteFile(testfile, bOut, 0644)
+				_ = ioutil.WriteFile(testfile, bOut, 0644)
 				return
 			}
 			got, want := string(bOut), string(bWant)
diff --git a/cmd/cue/cmd/custom.go b/cmd/cue/cmd/custom.go
index 74aaa24..63eb3d8 100644
--- a/cmd/cue/cmd/custom.go
+++ b/cmd/cue/cmd/custom.go
@@ -190,6 +190,9 @@
 			m.Lock()
 			obj := tasks.Lookup(t.name)
 			m.Unlock()
+			// NOTE: ignore the linter warning for the following line:
+			// itask.Context is an internal type and we want to break if any
+			// fields are added.
 			update, err := t.Run(&itask.Context{ctx, stdout, stderr}, obj)
 			if err == nil && update != nil {
 				m.Lock()
@@ -311,7 +314,7 @@
 					"when": "now",
 				}
 				enc := json.NewEncoder(w)
-				enc.Encode(d)
+				_ = enc.Encode(d)
 			}))
 		server = s.URL
 	})
diff --git a/cmd/cue/cmd/eval_test.go b/cmd/cue/cmd/eval_test.go
index ccb7fa7..1d7d20a 100644
--- a/cmd/cue/cmd/eval_test.go
+++ b/cmd/cue/cmd/eval_test.go
@@ -20,10 +20,10 @@
 	runCommand(t, newEvalCmd(), "eval")
 
 	cmd := newEvalCmd()
-	cmd.ParseFlags([]string{"-c", "-a"})
+	mustParseFlags(t, cmd, "-c", "-a")
 	runCommand(t, cmd, "eval_conc")
 
 	cmd = newEvalCmd()
-	cmd.ParseFlags([]string{"-c", "-e", "b.a.b", "-e", "b.idx"})
+	mustParseFlags(t, cmd, "-c", "-e", "b.a.b", "-e", "b.idx")
 	runCommand(t, cmd, "eval_expr")
 }
diff --git a/cmd/cue/cmd/get_go.go b/cmd/cue/cmd/get_go.go
index 7a05f68..20ce3cf 100644
--- a/cmd/cue/cmd/get_go.go
+++ b/cmd/cue/cmd/get_go.go
@@ -465,7 +465,7 @@
 			fmt.Fprintln(w)
 		}
 		fmt.Fprintln(w)
-		io.Copy(w, e.w)
+		_, _ = io.Copy(w, e.w)
 
 		file := filepath.Base(p.CompiledGoFiles[i])
 
@@ -473,7 +473,7 @@
 		file += "_gen.cue"
 		b, err := format.Source(w.Bytes())
 		if err != nil {
-			ioutil.WriteFile(filepath.Join(dir, file), w.Bytes(), 0644)
+			_ = ioutil.WriteFile(filepath.Join(dir, file), w.Bytes(), 0644)
 			fmt.Println(w.String())
 			fmt.Println(dir, file)
 			return err
diff --git a/cmd/cue/cmd/get_go_test.go b/cmd/cue/cmd/get_go_test.go
index 1034819..577ab8a 100644
--- a/cmd/cue/cmd/get_go_test.go
+++ b/cmd/cue/cmd/get_go_test.go
@@ -49,7 +49,7 @@
 	// for the common ground to not have breaking text if people run these
 	// test in GOPATH mode.
 	root := ""
-	filepath.Walk(tmp, func(path string, info os.FileInfo, err error) error {
+	_ = filepath.Walk(tmp, func(path string, info os.FileInfo, err error) error {
 		if root != "" {
 			return filepath.SkipDir
 		}
@@ -72,7 +72,7 @@
 	}
 
 	prefix := "testdata/pkg/cuelang.org/go/cmd/cue/cmd/testdata/code/go/"
-	filepath.Walk(dst, func(path string, info os.FileInfo, err error) error {
+	_ = filepath.Walk(dst, func(path string, info os.FileInfo, err error) error {
 		if info.IsDir() {
 			return nil
 		}
diff --git a/cmd/cue/cmd/import.go b/cmd/cue/cmd/import.go
index ce53316..54849d6 100644
--- a/cmd/cue/cmd/import.go
+++ b/cmd/cue/cmd/import.go
@@ -42,9 +42,6 @@
 	"golang.org/x/sync/errgroup"
 )
 
-// importCmd represents the import command
-var importCmd = newImportCmd()
-
 func newImportCmd() *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   "import",
@@ -531,7 +528,6 @@
 
 type listIndex struct {
 	index map[string]*listIndex
-	file  *ast.File // top-level only
 	field *ast.Field
 }
 
diff --git a/cmd/cue/cmd/import_test.go b/cmd/cue/cmd/import_test.go
index c0ce198..9d8d3cd 100644
--- a/cmd/cue/cmd/import_test.go
+++ b/cmd/cue/cmd/import_test.go
@@ -14,31 +14,29 @@
 
 package cmd
 
-import "testing"
+import (
+	"testing"
+)
 
 func TestImport(t *testing.T) {
 	cmd := newImportCmd()
-	cmd.ParseFlags([]string{
-		"-o", "-", "-f", "--files",
-	})
+	mustParseFlags(t, cmd,
+		"-o", "-", "-f", "--files")
 	runCommand(t, cmd, "import_files")
 
 	cmd = newImportCmd()
-	cmd.ParseFlags([]string{
-		"-o", "-", "-f", "-l", `"\(strings.ToLower(kind))" "\(name)"`,
-	})
+	mustParseFlags(t, cmd,
+		"-o", "-", "-f", "-l", `"\(strings.ToLower(kind))" "\(name)"`)
 	runCommand(t, cmd, "import_path")
 
 	cmd = newImportCmd()
-	cmd.ParseFlags([]string{
-		"-o", "-", "-f", "-l", `"\(strings.ToLower(kind))"`, "--list",
-	})
+	mustParseFlags(t, cmd,
+		"-o", "-", "-f", "-l", `"\(strings.ToLower(kind))"`, "--list")
 	runCommand(t, cmd, "import_list")
 
 	cmd = newImportCmd()
-	cmd.ParseFlags([]string{
+	mustParseFlags(t, cmd,
 		"-o", "-", "-f", "--list",
-		"-l", `"\(strings.ToLower(kind))" "\(name)"`, "--recursive",
-	})
+		"-l", `"\(strings.ToLower(kind))" "\(name)"`, "--recursive")
 	runCommand(t, cmd, "import_hoiststr")
 }
diff --git a/cmd/cue/cmd/interfaces/text.go b/cmd/cue/cmd/interfaces/text.go
index 0aa0270..8d716fc 100644
--- a/cmd/cue/cmd/interfaces/text.go
+++ b/cmd/cue/cmd/interfaces/text.go
@@ -20,3 +20,9 @@
 	textMarshaler   = encoding.TextMarshaler
 	textUnmarshaler = encoding.TextUnmarshaler
 )
+
+// Suppress incorrect linter errors (types are used).
+var (
+	_ = textMarshaler(nil)
+	_ = textUnmarshaler(nil)
+)
diff --git a/cmd/cue/cmd/interfaces/top.go b/cmd/cue/cmd/interfaces/top.go
index 0d2d9a5..2c06872 100644
--- a/cmd/cue/cmd/interfaces/top.go
+++ b/cmd/cue/cmd/interfaces/top.go
@@ -27,3 +27,11 @@
 		UnmarshalYAML(func(interface{}) error) error
 	}
 )
+
+// Suppress incorrect linter errors (types are used).
+var (
+	_ = jsonMarshaler(nil)
+	_ = jsonUnmarshaler(nil)
+	_ = yamlMarshal(nil)
+	_ = yamlUnmarshal(nil)
+)
diff --git a/cmd/cue/cmd/trim.go b/cmd/cue/cmd/trim.go
index cc79744..1ca999f 100644
--- a/cmd/cue/cmd/trim.go
+++ b/cmd/cue/cmd/trim.go
@@ -535,17 +535,6 @@
 	return false
 }
 
-func deleteNode(a []ast.Node, n ast.Node) []ast.Node {
-	k := 0
-	for _, e := range a {
-		if e != n {
-			a[k] = e
-			k++
-		}
-	}
-	return a[:k]
-}
-
 type key struct {
 	label  string
 	hidden bool
diff --git a/cmd/cue/cmd/trim_test.go b/cmd/cue/cmd/trim_test.go
index 5c5d8d0..bc8001f 100644
--- a/cmd/cue/cmd/trim_test.go
+++ b/cmd/cue/cmd/trim_test.go
@@ -20,6 +20,6 @@
 
 func TestTrim(t *testing.T) {
 	cmd := newTrimCmd()
-	cmd.ParseFlags([]string{"-o", "-"})
+	mustParseFlags(t, cmd, "-o", "-")
 	runCommand(t, cmd, "trim")
 }
diff --git a/cmd/cue/cmd/vet.go b/cmd/cue/cmd/vet.go
index a55a5aa..70e7452 100644
--- a/cmd/cue/cmd/vet.go
+++ b/cmd/cue/cmd/vet.go
@@ -72,7 +72,8 @@
 			if !shown && err == nil {
 				shown = true
 				p := message.NewPrinter(getLang())
-				p.Fprintln(w, "some instances are incomplete; use the -c flag to show errors or suppress this message")
+				_, _ = p.Fprintln(w,
+					"some instances are incomplete; use the -c flag to show errors or suppress this message")
 			}
 		}
 		exitIfErr(cmd, inst, err, false)