Fix subtraction underflow bug

CHANGELOG.md

@@ -8,6 +8,7 @@ Bug fixes
 ---------
 
 * (Fuzzing) An integer-overflow bug from an inclusive range in the bits iterator is fixed.
+* (Fuzzing) An integer-underflow bug from an inclusive range is fixed.
 
 Enhancements
 ------------

src/eval/target.rs

@@ -1,6 +1,6 @@
 //! Type to hold a mutable reference to the target of an evaluation.
 
 use crate::{Dynamic, EvalAltResult, Position, RhaiError, RhaiResultOf};
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
 use std::{
@@ -404,6 +404,8 @@
                 let ve = if *exclusive {
                     let end = if *end > n { n } else { *end };
                     s.chars().skip(end)
+                } else if n == 0 {
+                    s.chars().skip(usize::MAX)
                 } else {
                     let end = if *end >= n { n - 1 } else { *end };
                     s.chars().skip(end + 1)