diff --git a/rinja_derive/src/tests.rs b/rinja_derive/src/tests.rs
index 2ef24157a..57e36ec44 100644
--- a/rinja_derive/src/tests.rs
+++ b/rinja_derive/src/tests.rs
@@ -407,6 +407,22 @@ match (
         "{% if y is defined && !(y) %}bla{% endif %}",
         r#"if *(&(!(self.y)) as &::core::primitive::bool) {
     writer.write_str("bla")?;
+}"#,
+        &[("y", "bool")],
+        3,
+    );
+    compare(
+        "{% if y is not defined || !y %}bla{% endif %}",
+        r#"if *(&(!self.y) as &::core::primitive::bool) {
+    writer.write_str("bla")?;
+}"#,
+        &[("y", "bool")],
+        3,
+    );
+    compare(
+        "{% if y is not defined || !(y) %}bla{% endif %}",
+        r#"if *(&(!(self.y)) as &::core::primitive::bool) {
+    writer.write_str("bla")?;
 }"#,
         &[("y", "bool")],
         3,