From: Mark Thom <markjordanthom@gmail.com>
Date: Sat, 29 Jan 2022 19:50:09 +0000 (-0700)
Subject: add range check to arg/3 (#1250)
X-Git-Tag: v0.9.0^2~37^2
X-Git-Url: https://git.sagredo.dev/?a=commitdiff_plain;h=4ddacc707d5a9afd42ae598ceeb00a9285d8cd17;p=scryer-prolog.git

add range check to arg/3 (#1250)
---

diff --git a/src/machine/machine_state_impl.rs b/src/machine/machine_state_impl.rs
index 373f8704..50b5144c 100644
--- a/src/machine/machine_state_impl.rs
+++ b/src/machine/machine_state_impl.rs
@@ -2080,7 +2080,7 @@ impl MachineState {
 
                 let n = match n {
                     Number::Fixnum(n) => n.get_num() as usize,
-                    Number::Integer(n) => n.to_usize().unwrap(),
+                    Number::Integer(n) if *n >= 0 && *n <= std::usize::MAX => n.to_usize().unwrap(),
                     _ => {
                         self.fail = true;
                         return Ok(());