1 files changed, 1 insertions, 1 deletions
diff --git a/src/vm.c b/src/vm.c
index 70c27da57..43c3d120f 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -186,7 +186,7 @@ stack_extend_alloc(mrb_state *mrb, mrb_int room)
 
   if (off > size) size = off;
 #ifdef MRB_STACK_EXTEND_DOUBLING
-  if (room <= size)
+  if (room <= (size_t)size)
     size *= 2;
   else
     size += room;