diff --git a/lib/src/fileset.rs b/lib/src/fileset.rs
index 2c94684d7..f6e35822c 100644
--- a/lib/src/fileset.rs
+++ b/lib/src/fileset.rs
@@ -396,11 +396,11 @@ static BUILTIN_FUNCTION_MAP: Lazy<HashMap<&'static str, FilesetFunction>> = Lazy
     // code completion inside macro is quite restricted.
     let mut map: HashMap<&'static str, FilesetFunction> = HashMap::new();
     map.insert("none", |_ctx, function| {
-        fileset_parser::expect_no_arguments(function)?;
+        function.expect_no_arguments()?;
         Ok(FilesetExpression::none())
     });
     map.insert("all", |_ctx, function| {
-        fileset_parser::expect_no_arguments(function)?;
+        function.expect_no_arguments()?;
         Ok(FilesetExpression::all())
     });
     map
diff --git a/lib/src/fileset_parser.rs b/lib/src/fileset_parser.rs
index 42b5dfef2..80b37d2a7 100644
--- a/lib/src/fileset_parser.rs
+++ b/lib/src/fileset_parser.rs
@@ -342,14 +342,16 @@ pub fn parse_program_or_bare_string(text: &str) -> FilesetParseResult<Expression
     Ok(ExpressionNode::new(expr, span))
 }
 
-pub fn expect_no_arguments(function: &FunctionCallNode) -> FilesetParseResult<()> {
-    if function.args.is_empty() {
-        Ok(())
-    } else {
-        Err(FilesetParseError::invalid_arguments(
-            function,
-            "Expected 0 arguments",
-        ))
+impl<'i> FunctionCallNode<'i> {
+    pub fn expect_no_arguments(&self) -> FilesetParseResult<()> {
+        if self.args.is_empty() {
+            Ok(())
+        } else {
+            Err(FilesetParseError::invalid_arguments(
+                self,
+                "Expected 0 arguments",
+            ))
+        }
     }
 }