diff --git a/.github/workflows/upstream pretest.yaml b/.github/workflows/upstream pretest.yaml
index 83d69267..3c99859d 100644
--- a/.github/workflows/upstream pretest.yaml	
+++ b/.github/workflows/upstream pretest.yaml	
@@ -113,7 +113,7 @@ jobs:
                             $head_sha_by_pr.Add($pr_num, $sha)
                         }
                         
-                        $pretest_prs = @{}
+                        $pretest_prs = @()
                         foreach ($l in Get-GitRemoteBranches $fork_url 'refs/heads/pretest/*') {
                             $sha = $l.sha
                             $pr_num = $l.matches[1]