1 files changed, 1 insertions, 0 deletions
diff --git a/src/codegen.c b/src/codegen.c
index 418e1f371..c869285d9 100644
--- a/src/codegen.c
+++ b/src/codegen.c
@@ -719,6 +719,7 @@ attrsym(codegen_scope *s, mrb_sym a)
                                  + 1 /* '=' */
                                  + 1 /* '\0' */
                                  );
+  mrb_assert(len <= SIZE_MAX);
   memcpy(name2, name, (size_t)len);
   name2[len] = '=';
   name2[len+1] = '\0';