diff --git a/src/parse/variable.rs b/src/parse/variable.rs
index b712947..3ffc1a7 100644
--- a/src/parse/variable.rs
+++ b/src/parse/variable.rs
@@ -23,7 +23,8 @@ impl VariableValue {
 
 impl<'a> Parser<'a> {
     pub(super) fn parse_variable_declaration(&mut self) -> SassResult<()> {
-        assert!(matches!(self.toks.next(), Some(Token { kind: '$', .. })));
+        let next = self.toks.next();
+        assert!(matches!(next, Some(Token { kind: '$', .. })));
         let ident: Identifier = self.parse_identifier_no_interpolation(false)?.node.into();
         self.whitespace_or_comment();