diff --git a/ext/coverage/coverage.c b/ext/coverage/coverage.c
index af0cb87c66..ed4a69d3db 100644
--- a/ext/coverage/coverage.c
+++ b/ext/coverage/coverage.c
@@ -36,7 +36,7 @@ static int
 coverage_clear_result_i(st_data_t key, st_data_t val, st_data_t h)
 {
     VALUE coverage = (VALUE)val;
-    rb_ary_clear((VALUE)val);
+    rb_ary_clear(coverage);
     return ST_CONTINUE;
 }