🚨 Add some tooling/ linting

errgroup_test.go

@@ -43,8 +43,6 @@ func ExampleGroup_justErrors() {
 		"http://www.somestupidname.com/",
 	}
 	for _, url := range urls {
-		// Launch a goroutine to fetch the URL.
-		url := url // https://golang.org/doc/faq#closures_and_goroutines
 		g.Go(func() error {
 			// Fetch the URL.
 			resp, err := http.Get(url)
@@ -71,7 +69,6 @@ func ExampleGroup_parallel() {
 		searches := []Search{Web, Image, Video}
 		results := make([]Result, len(searches))
 		for i, search := range searches {
-			i, search := i, search // https://golang.org/doc/faq#closures_and_goroutines
 			g.Go(func() error {
 				result, err := search(ctx, query)
 				if err == nil {
@@ -120,7 +117,6 @@ func TestZeroGroup(t *testing.T) {
 
 		var firstErr error
 		for i, err := range tc.errs {
-			err := err
 			g.Go(func() error { return err })
 
 			if firstErr == nil && err != nil {
@@ -153,7 +149,6 @@ func TestWithContext(t *testing.T) {
 		g, ctx := errgroup.WithContext(context.Background())
 
 		for _, err := range tc.errs {
-			err := err
 			g.Go(func() error { return err })
 		}
 
@@ -267,7 +262,6 @@ func TestCancelCause(t *testing.T) {
 		g, ctx := errgroup.WithContext(context.Background())
 
 		for _, err := range tc.errs {
-			err := err
 			g.TryGo(func() error { return err })
 		}