Cargo check fix

Author: romanoff

src/ast/helpers/stmt_data_loading.rs

@@ -21,6 +21,8 @@
 
 #[cfg(not(feature = "std"))]
 use alloc::string::String;
+#[cfg(not(feature = "std"))]
+use alloc::vec::Vec;
 use core::fmt;
 
 #[cfg(feature = "serde")]