OOP support.

src/error.rs

@@ -3,7 +3,13 @@
 use crate::result::EvalAltResult;
 use crate::token::Position;
 
-use crate::stdlib::{boxed::Box, char, error::Error, fmt, string::String};
+use crate::stdlib::{
+    boxed::Box,
+    char,
+    error::Error,
+    fmt,
+    string::{String, ToString},
+};
 
 /// Error when tokenizing the script text.
 #[derive(Debug, Eq, PartialEq, Clone, Hash)]