diff --git a/src/preserves.nim b/src/preserves.nim
index 541a751..9cdc185 100644
--- a/src/preserves.nim
+++ b/src/preserves.nim
@@ -890,7 +890,7 @@ proc fromPreserve*[T, E](v: var T; pr: Preserve[E]): bool =
     of pkRecord, pkSequence:
       if pr.len <= tupleLen(T):
         result = true
-        var i: int
+        var i {.used.}: int
         for f in fields(v):
           if result and i < pr.len:
             result = result and fromPreserve(f, pr[i])