diff --git a/src/nagini_translation/resources/bool.sil b/src/nagini_translation/resources/bool.sil
index 6b61505a..377d4a29 100644
--- a/src/nagini_translation/resources/bool.sil
+++ b/src/nagini_translation/resources/bool.sil
@@ -223,7 +223,7 @@ function int___mul__(self: Int, other: Int): Int
 
 function int___pow__(self: Int, other: Int): Int
     decreases _
-    requires other >= 0
+    requires @error("** is currently only supported for non-negative exponents.")(other >= 0)
 {
     ___pow(self, other)
 }
diff --git a/src/nagini_translation/translators/expression.py b/src/nagini_translation/translators/expression.py
index 555f8f72..c9214860 100644
--- a/src/nagini_translation/translators/expression.py
+++ b/src/nagini_translation/translators/expression.py
@@ -994,6 +994,8 @@ def translate_operator(self, left: Expr, right: Expr, left_type: PythonType,
         
         if left_type == right_type or isinstance(right_type, TypeVar):
             call_stmt, call = self.get_func_or_method_call(left_type, LEFT_OPERATOR_FUNCTIONS[type(node.op)], [left, right], [left_type, right_type], node, ctx)
+            if call is None:
+                raise UnsupportedException(node, "Unsupported binary operator")
             return stmt + call_stmt, call
             
         else: