From: Emilie Burgun <emilie@shadamethyst.xyz>
Date: Mon, 20 Jan 2025 10:10:16 +0000 (+0100)
Subject: Fix `X is gcd(1, 2 ^ 64)` triggering a panic
X-Git-Tag: v0.10.0~77^2~3
X-Git-Url: https://git.sagredo.dev/?a=commitdiff_plain;h=e2d1a2b6bc9943aec76fcc085beec0600c33313e;p=scryer-prolog.git

Fix `X is gcd(1, 2 ^ 64)` triggering a panic

The implementation for gcd/2 would cast the second argument to an isize.
---

diff --git a/src/machine/arithmetic_ops.rs b/src/machine/arithmetic_ops.rs
index 2d1bdc65..3cd1d9d8 100644
--- a/src/machine/arithmetic_ops.rs
+++ b/src/machine/arithmetic_ops.rs
@@ -947,8 +947,7 @@ pub(crate) fn gcd(n1: Number, n2: Number, arena: &mut Arena) -> Result<Number, M
             Ok(Number::arena_from(Integer::from(n2_clone.gcd(&n1)), arena))
         }
         (Number::Integer(n1), Number::Integer(n2)) => {
-            let n2: isize = (&*n2).try_into().unwrap();
-            let value: Integer = (&*n1).gcd(&Integer::from(n2)).into();
+            let value: Integer = (&*n1).gcd(&*n2).into();
             Ok(Number::arena_from(value, arena))
         }
         (Number::Float(f), _) | (_, Number::Float(f)) => {