diff --git a/prism_compile.c b/prism_compile.c
index de3a294933..50a8c87e7d 100644
--- a/prism_compile.c
+++ b/prism_compile.c
@@ -5676,7 +5676,7 @@ pm_compile_node(rb_iseq_t *iseq, const pm_node_t *node, LINK_ANCHOR *const ret,
             // own arrays, followed by a newarray, and then continually
             // concat the arrays with the SplatNode nodes.
             const int max_new_array_size = 0x100;
-            const int min_tmp_array_size = 0x40;
+            const unsigned int min_tmp_array_size = 0x40;
 
             int new_array_size = 0;
             bool first_chunk = true;