Small parser changes.

dmc-lib/src/parser.rs

@@ -96,7 +96,7 @@ struct Parser<'a> {
     lexer: Lexer<'a>,
     current: Option<Token>,
     lookahead: Option<Token>,
-    node_index: usize,
+    node_id: usize,
 }
 
 impl<'a> Parser<'a> {
@@ -106,7 +106,7 @@ impl<'a> Parser<'a> {
             lexer: Lexer::new(input),
             current: None,
             lookahead: None,
-            node_index: 0,
+            node_id: 0,
         }
     }
 
@@ -212,6 +212,7 @@ impl<'a> Parser<'a> {
             .with_primary_label_message(&format!("Expected {}.", Self::join_kinds(kinds)))
     }
 
+    #[must_use]
     fn expect_advance(&mut self, token_kind: TokenKind) -> (Option<Token>, Diagnostics) {
         match self.current.take() {
             None => (
@@ -290,6 +291,12 @@ impl<'a> Parser<'a> {
         self.sample_input(token.start(), token.end())
     }
 
+    fn next_node_id(&mut self) -> usize {
+        let node_id = self.node_id;
+        self.node_id += 1;
+        node_id
+    }
+
     fn compilation_unit(&mut self) -> ParseResult<CompilationUnit> {
         let mut functions: Vec<Function> = vec![];
         let mut extern_functions: Vec<ExternFunction> = vec![];