all: update references to symbols moved from io/ioutil to io

The old ioutil references are still valid, but update our code
to reflect best practices and get used to the new locations.

Code compiled with the bootstrap toolchain
(cmd/asm, cmd/dist, cmd/compile, debug/elf)
must remain Go 1.4-compatible and is excluded.
Also excluded vendored code.

For #41190.

Change-Id: I6d86f2bf7bc37a9d904b6cee3fe0c7af6d94d5b1
Reviewed-on: https://go-review.googlesource.com/c/go/+/263142
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>

2 files changed, 11 insertions, 11 deletions

diff --git a/src/html/template/clone_test.go b/src/html/template/clone_test.go
index c9c619f0d4..7cb1b9ca06 100644
--- a/src/html/template/clone_test.go
+++ b/src/html/template/clone_test.go
@@ -8,7 +8,7 @@ import (
 	"bytes"
 	"errors"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"strings"
 	"sync"
 	"testing"
@@ -171,7 +171,7 @@ func TestCloneThenParse(t *testing.T) {
 		t.Error("adding a template to a clone added it to the original")
 	}
 	// double check that the embedded template isn't available in the original
-	err := t0.ExecuteTemplate(ioutil.Discard, "a", nil)
+	err := t0.ExecuteTemplate(io.Discard, "a", nil)
 	if err == nil {
 		t.Error("expected 'no such template' error")
 	}
@@ -185,13 +185,13 @@ func TestFuncMapWorksAfterClone(t *testing.T) {
 
 	// get the expected error output (no clone)
 	uncloned := Must(New("").Funcs(funcs).Parse("{{customFunc}}"))
-	wantErr := uncloned.Execute(ioutil.Discard, nil)
+	wantErr := uncloned.Execute(io.Discard, nil)
 
 	// toClone must be the same as uncloned. It has to be recreated from scratch,
 	// since cloning cannot occur after execution.
 	toClone := Must(New("").Funcs(funcs).Parse("{{customFunc}}"))
 	cloned := Must(toClone.Clone())
-	gotErr := cloned.Execute(ioutil.Discard, nil)
+	gotErr := cloned.Execute(io.Discard, nil)
 
 	if wantErr.Error() != gotErr.Error() {
 		t.Errorf("clone error message mismatch want %q got %q", wantErr, gotErr)
@@ -213,7 +213,7 @@ func TestTemplateCloneExecuteRace(t *testing.T) {
 		go func() {
 			defer wg.Done()
 			for i := 0; i < 100; i++ {
-				if err := tmpl.Execute(ioutil.Discard, "data"); err != nil {
+				if err := tmpl.Execute(io.Discard, "data"); err != nil {
 					panic(err)
 				}
 			}
@@ -237,7 +237,7 @@ func TestCloneGrowth(t *testing.T) {
 	tmpl = Must(tmpl.Clone())
 	Must(tmpl.Parse(`{{define "B"}}Text{{end}}`))
 	for i := 0; i < 10; i++ {
-		tmpl.Execute(ioutil.Discard, nil)
+		tmpl.Execute(io.Discard, nil)
 	}
 	if len(tmpl.DefinedTemplates()) > 200 {
 		t.Fatalf("too many templates: %v", len(tmpl.DefinedTemplates()))
@@ -257,7 +257,7 @@ func TestCloneRedefinedName(t *testing.T) {
 	for i := 0; i < 2; i++ {
 		t2 := Must(t1.Clone())
 		t2 = Must(t2.New(fmt.Sprintf("%d", i)).Parse(page))
-		err := t2.Execute(ioutil.Discard, nil)
+		err := t2.Execute(io.Discard, nil)
 		if err != nil {
 			t.Fatal(err)
 		}
diff --git a/src/html/template/exec_test.go b/src/html/template/exec_test.go
index fc76ee40e5..232945a0bb 100644
--- a/src/html/template/exec_test.go
+++ b/src/html/template/exec_test.go
@@ -11,7 +11,7 @@ import (
 	"errors"
 	"flag"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"reflect"
 	"strings"
 	"testing"
@@ -1335,7 +1335,7 @@ func TestExecuteGivesExecError(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	err = tmpl.Execute(ioutil.Discard, 0)
+	err = tmpl.Execute(io.Discard, 0)
 	if err == nil {
 		t.Fatal("expected error; got none")
 	}
@@ -1481,7 +1481,7 @@ func TestEvalFieldErrors(t *testing.T) {
 	for _, tc := range tests {
 		t.Run(tc.name, func(t *testing.T) {
 			tmpl := Must(New("tmpl").Parse(tc.src))
-			err := tmpl.Execute(ioutil.Discard, tc.value)
+			err := tmpl.Execute(io.Discard, tc.value)
 			got := "<nil>"
 			if err != nil {
 				got = err.Error()
@@ -1498,7 +1498,7 @@ func TestMaxExecDepth(t *testing.T) {
 		t.Skip("skipping in -short mode")
 	}
 	tmpl := Must(New("tmpl").Parse(`{{template "tmpl" .}}`))
-	err := tmpl.Execute(ioutil.Discard, nil)
+	err := tmpl.Execute(io.Discard, nil)
 	got := "<nil>"
 	if err != nil {
 		got = err.Error()