From 15db77558c5b7c1a981eb9e15dacaeb393852d11 Mon Sep 17 00:00:00 2001
From: Mark Thom <markjordanthom@gmail.com>
Date: Sat, 23 May 2020 13:33:05 -0600
Subject: [PATCH] throw evaluable type error for unrecognized atoms in
 arith_eval_by_metacall

---
 src/prolog/machine/arithmetic_ops.rs | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/prolog/machine/arithmetic_ops.rs b/src/prolog/machine/arithmetic_ops.rs
index 61627aa8..45aecb9b 100644
--- a/src/prolog/machine/arithmetic_ops.rs
+++ b/src/prolog/machine/arithmetic_ops.rs
@@ -269,6 +269,18 @@ impl MachineState {
                         caller,
                     ));
                 }
+                &HeapCellValue::Atom(ref name, _) => {
+                    let evaluable_stub = MachineError::functor_stub(name.clone(), 0);
+
+                    return Err(self.error_form(
+                        MachineError::type_error(
+                            self.heap.h(),
+                            ValidType::Evaluable,
+                            evaluable_stub,
+                        ),
+                        caller,
+                    ));
+                }
                 &HeapCellValue::Addr(addr) if addr.is_ref() => {
                     return Err(self.error_form(
                         MachineError::instantiation_error(),
-- 
2.54.0