diff --git a/promql/engine.go b/promql/engine.go
index eac3b64093..a5b66052f3 100644
--- a/promql/engine.go
+++ b/promql/engine.go
@@ -1259,7 +1259,7 @@ func (enh *EvalNodeHelper) resetHistograms(inVec Vector, arg parser.Expr) annota
 // the given funcCall with the values computed for each expression at that
 // step. The return value is the combination into time series of all the
 // function call results.
-// The prepSeries function (if provided) can be used to prepare the helper
+// The matching (if provided) can be used to prepare the helper
 // for each series, then passed to each call funcCall.
 func (ev *evaluator) rangeEval(ctx context.Context, matching *parser.VectorMatching, funcCall func([]Vector, Matrix, [][]EvalSeriesHelper, *EvalNodeHelper) (Vector, annotations.Annotations), exprs ...parser.Expr) (Matrix, annotations.Annotations) {
 	numSteps := int((ev.endTimestamp-ev.startTimestamp)/ev.interval) + 1