remove unwrap in Value::is_null

src/value/mod.rs

@@ -116,7 +116,12 @@ impl Value {
                 self.clone().eval(span)?.is_null(span)?
             }
             Self::List(v, _, Brackets::Bracketed) if v.is_empty() => false,
-            Self::List(v, ..) => v.iter().all(|f| f.is_null(span).unwrap()),
+            Self::List(v, ..) => v
+                .iter()
+                .map(|f| Ok(f.is_null(span)?))
+                .collect::<SassResult<Vec<bool>>>()?
+                .into_iter()
+                .all(|f| f),
             _ => false,
         })
     }

tests/error.rs

@@ -230,3 +230,7 @@ error!(
     "a {color: \"", "Error: Expected \"."
 );
 error!(nothing_after_sgl_quote, "a {color: '", "Error: Expected '.");
+error!(
+    invalid_binop_in_list,
+    "a {color: foo % bar, baz;}", "Error: Undefined operation \"foo % bar\"."
+);