diff --git a/src/embed_tests/TestPyObject.cs b/src/embed_tests/TestPyObject.cs
index d0d8eab45..f7f07e6a4 100644
--- a/src/embed_tests/TestPyObject.cs
+++ b/src/embed_tests/TestPyObject.cs
@@ -71,5 +71,13 @@ public void AsManagedObjectInvalidCast()
             var list = PythonEngine.Eval("list");
             Assert.Throws<InvalidCastException>(() => list.AsManagedObject(typeof(int)));
         }
+
+        [Test]
+        public void UnaryMinus_ThrowsOnBadType()
+        {
+            dynamic list = new PyList();
+            var error = Assert.Throws<PythonException>(() => list = -list);
+            Assert.AreEqual("TypeError", error.Type.Name);
+        }
     }
 }
diff --git a/src/runtime/pyobject.cs b/src/runtime/pyobject.cs
index 55e76019b..4a61e65e8 100644
--- a/src/runtime/pyobject.cs
+++ b/src/runtime/pyobject.cs
@@ -1398,6 +1398,7 @@ public override bool TryBinaryOperation(BinaryOperationBinder binder, object arg
                     result = null;
                     return false;
             }
+            Exceptions.ErrorCheck(res);
             result = CheckNone(new PyObject(res));
             return true;
         }
@@ -1450,6 +1451,7 @@ public override bool TryUnaryOperation(UnaryOperationBinder binder, out object r
                     result = null;
                     return false;
             }
+            Exceptions.ErrorCheck(res);
             result = CheckNone(new PyObject(res));
             return true;
         }