diff --git a/codegen/type.go b/codegen/type.go
index 9b3b799ae5c..276b4130847 100644
--- a/codegen/type.go
+++ b/codegen/type.go
@@ -105,7 +105,10 @@ func (t Type) unmarshal(result, raw string, remainingMods []string, depth int) s
 		var rawIf = "rawIf" + strconv.Itoa(depth)
 		var index = "idx" + strconv.Itoa(depth)
 
-		return tpl(`{{.rawSlice}} := {{.raw}}.([]interface{})
+		return tpl(`var {{.rawSlice}} []interface{}
+			if {{.raw}} != nil {
+				{{.rawSlice}} = {{.raw}}.([]interface{})
+			}
 			{{.result}} = make({{.type}}, len({{.rawSlice}}))
 			for {{.index}} := range {{.rawSlice}} {
 				{{ .next -}}
diff --git a/example/dataloader/generated.go b/example/dataloader/generated.go
index 0b0b4d87e71..69cb4b6e695 100644
--- a/example/dataloader/generated.go
+++ b/example/dataloader/generated.go
@@ -459,10 +459,16 @@ func (ec *executionContext) _Query_torture(ctx context.Context, field graphql.Co
 	var arg0 [][]int
 	if tmp, ok := field.Args["customerIds"]; ok {
 		var err error
-		rawIf1 := tmp.([]interface{})
+		var rawIf1 []interface{}
+		if tmp != nil {
+			rawIf1 = tmp.([]interface{})
+		}
 		arg0 = make([][]int, len(rawIf1))
 		for idx1 := range rawIf1 {
-			rawIf2 := rawIf1[idx1].([]interface{})
+			var rawIf2 []interface{}
+			if rawIf1[idx1] != nil {
+				rawIf2 = rawIf1[idx1].([]interface{})
+			}
 			arg0[idx1] = make([]int, len(rawIf2))
 			for idx2 := range rawIf2 {
 				arg0[idx1][idx2], err = graphql.UnmarshalInt(rawIf2[idx2])