diff --git a/src/cprover/axioms.cpp b/src/cprover/axioms.cpp
index e381f17abbb..e38b930fca3 100644
--- a/src/cprover/axioms.cpp
+++ b/src/cprover/axioms.cpp
@@ -65,9 +65,13 @@ void axiomst::evaluate_fc()
       if(a_it->state() != b_it->state())
         continue;
 
+      // Skip pairs with incompatible address types — they can never
+      // point to the same location.
+      if(a_it->address().type() != b_it->address().type())
+        continue;
+
       auto a_op = a_it->address();
-      auto b_op = typecast_exprt::conditional_cast(
-        b_it->address(), a_it->address().type());
+      auto b_op = b_it->address();
       auto operands_equal = equal_exprt(a_op, b_op);
       auto implication = implies_exprt(
         operands_equal,