1 files changed, 1 insertions, 0 deletions
diff --git a/internal/array.h b/internal/array.h
index 17d91a800b..a0d16dec3f 100644
--- a/internal/array.h
+++ b/internal/array.h
@@ -35,6 +35,7 @@ void rb_ary_cancel_sharing(VALUE ary);
 size_t rb_ary_size_as_embedded(VALUE ary);
 void rb_ary_make_embedded(VALUE ary);
 bool rb_ary_embeddable_p(VALUE ary);
+VALUE rb_ary_diff(VALUE ary1, VALUE ary2);
 
 static inline VALUE rb_ary_entry_internal(VALUE ary, long offset);
 static inline bool ARY_PTR_USING_P(VALUE ary);