diff --git a/rules/ast/functions.go b/rules/ast/functions.go
index 6276f4429..a77ab9819 100644
--- a/rules/ast/functions.go
+++ b/rules/ast/functions.go
@@ -137,7 +137,7 @@ func rateImpl(timestamp time.Time, view *viewAdapter, args []Node) interface{} {
 	// MatrixLiteral exists). Find a better way of getting the duration of a
 	// matrix, such as looking at the samples themselves.
 	interval := args[0].(*MatrixLiteral).interval
-	for i, _ := range vector {
+	for i := range vector {
 		vector[i].Value /= model.SampleValue(interval / time.Second)
 	}
 	return vector
diff --git a/rules/rules_test.go b/rules/rules_test.go
index 78431cbc7..f4083e161 100644
--- a/rules/rules_test.go
+++ b/rules/rules_test.go
@@ -219,8 +219,8 @@ var expressionTests = []struct {
 		intervalRanges: 1,
 	}, {
 		// Lower-cased aggregation operators should work too.
-		expr:           "sum(http_requests) by (job) + min(http_requests) by (job) + max(http_requests) by (job) + avg(http_requests) by (job)",
-		output:					[]string{
+		expr: "sum(http_requests) by (job) + min(http_requests) by (job) + max(http_requests) by (job) + avg(http_requests) by (job)",
+		output: []string{
 			"http_requests{job='app-server'} => 4550 @[%v]",
 			"http_requests{job='api-server'} => 1750 @[%v]",
 		},