diff --git a/crates/fuse-ast/src/ast.rs b/crates/fuse-ast/src/ast.rs
index 5b0ee05..01ac54d 100644
--- a/crates/fuse-ast/src/ast.rs
+++ b/crates/fuse-ast/src/ast.rs
@@ -1,6 +1,6 @@
 use fuse_common::Span;
 use fuse_common_proc::serializable;
-use std::rc::Rc;
+use std::{cell::Cell, rc::Rc};
 
 #[serializable]
 #[derive(Debug)]
@@ -185,8 +185,13 @@ pub enum InterpolationFormat {
 pub struct Identifier {
     pub span: Span,
     pub name: Atom,
+    pub reference: Cell<Option<ReferenceId>>,
 }
 
+#[serializable]
+#[derive(Debug, PartialEq, Clone, Copy)]
+pub struct ReferenceId(u32);
+
 #[serializable]
 #[derive(Debug, PartialEq)]
 pub struct Function {
diff --git a/crates/fuse-parser/src/parsers/expressions.rs b/crates/fuse-parser/src/parsers/expressions.rs
index 5345716..8538713 100644
--- a/crates/fuse-parser/src/parsers/expressions.rs
+++ b/crates/fuse-parser/src/parsers/expressions.rs
@@ -1,3 +1,5 @@
+use std::cell::Cell;
+
 use crate::{lexer::TokenKind, Parser, ParserResult};
 use fuse_ast::{
     ArrayExpressionElement, BinaryOperator, BooleanLiteral, ConstructionExpression,
@@ -71,6 +73,7 @@ impl<'a> Parser<'a> {
         Ok(Identifier {
             span: token.span(),
             name: self.ast.atom(view),
+            reference: Cell::default(),
         })
     }
 
diff --git a/crates/fuse-parser/tests/cases/fail/variable-declaration-01/ast.snap b/crates/fuse-parser/tests/cases/fail/variable-declaration-01/ast.snap
index 42b04b4..a1dc37d 100644
--- a/crates/fuse-parser/tests/cases/fail/variable-declaration-01/ast.snap
+++ b/crates/fuse-parser/tests/cases/fail/variable-declaration-01/ast.snap
@@ -29,6 +29,7 @@ Some(Chunk(
                 end: 10,
               ),
               name: Atom("name"),
+              reference: None,
             ),
             mutable: false,
           )),
diff --git a/crates/fuse-parser/tests/cases/pass/binary-operator-01/ast.snap b/crates/fuse-parser/tests/cases/pass/binary-operator-01/ast.snap
index 961f43e..a19345d 100644
--- a/crates/fuse-parser/tests/cases/pass/binary-operator-01/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/binary-operator-01/ast.snap
@@ -22,6 +22,7 @@ Some(Chunk(
             end: 1,
           ),
           name: Atom("x"),
+          reference: None,
         )),
         rhs: BinaryOperator(BinaryOperator(
           kind: LogicalAnd(Span(
@@ -34,6 +35,7 @@ Some(Chunk(
               end: 5,
             ),
             name: Atom("a"),
+            reference: None,
           )),
           rhs: Identifier(Identifier(
             span: Span(
@@ -41,6 +43,7 @@ Some(Chunk(
               end: 11,
             ),
             name: Atom("b"),
+            reference: None,
           )),
         )),
       ))),
diff --git a/crates/fuse-parser/tests/cases/pass/binary-operator-02/ast.snap b/crates/fuse-parser/tests/cases/pass/binary-operator-02/ast.snap
index 70571b5..3942160 100644
--- a/crates/fuse-parser/tests/cases/pass/binary-operator-02/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/binary-operator-02/ast.snap
@@ -22,6 +22,7 @@ Some(Chunk(
             end: 1,
           ),
           name: Atom("x"),
+          reference: None,
         )),
         rhs: BinaryOperator(BinaryOperator(
           kind: LogicalAnd(Span(
@@ -39,6 +40,7 @@ Some(Chunk(
                 end: 5,
               ),
               name: Atom("a"),
+              reference: None,
             )),
             rhs: Identifier(Identifier(
               span: Span(
@@ -46,6 +48,7 @@ Some(Chunk(
                 end: 11,
               ),
               name: Atom("b"),
+              reference: None,
             )),
           )),
           rhs: Identifier(Identifier(
@@ -54,6 +57,7 @@ Some(Chunk(
               end: 17,
             ),
             name: Atom("c"),
+            reference: None,
           )),
         )),
       ))),
diff --git a/crates/fuse-parser/tests/cases/pass/binary-operator-03/ast.snap b/crates/fuse-parser/tests/cases/pass/binary-operator-03/ast.snap
index 7b9b849..085cb03 100644
--- a/crates/fuse-parser/tests/cases/pass/binary-operator-03/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/binary-operator-03/ast.snap
@@ -22,6 +22,7 @@ Some(Chunk(
             end: 1,
           ),
           name: Atom("x"),
+          reference: None,
         )),
         rhs: BinaryOperator(BinaryOperator(
           kind: LogicalOr(Span(
@@ -39,6 +40,7 @@ Some(Chunk(
                 end: 5,
               ),
               name: Atom("a"),
+              reference: None,
             )),
             rhs: Identifier(Identifier(
               span: Span(
@@ -46,6 +48,7 @@ Some(Chunk(
                 end: 11,
               ),
               name: Atom("b"),
+              reference: None,
             )),
           )),
           rhs: Identifier(Identifier(
@@ -54,6 +57,7 @@ Some(Chunk(
               end: 16,
             ),
             name: Atom("c"),
+            reference: None,
           )),
         )),
       ))),
diff --git a/crates/fuse-parser/tests/cases/pass/binary-operator-04/ast.snap b/crates/fuse-parser/tests/cases/pass/binary-operator-04/ast.snap
index a130e21..8d7f1b8 100644
--- a/crates/fuse-parser/tests/cases/pass/binary-operator-04/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/binary-operator-04/ast.snap
@@ -22,6 +22,7 @@ Some(Chunk(
             end: 1,
           ),
           name: Atom("x"),
+          reference: None,
         )),
         rhs: BinaryOperator(BinaryOperator(
           kind: Minus(Span(
diff --git a/crates/fuse-parser/tests/cases/pass/binary-operator-05/ast.snap b/crates/fuse-parser/tests/cases/pass/binary-operator-05/ast.snap
index a763744..2ae5b47 100644
--- a/crates/fuse-parser/tests/cases/pass/binary-operator-05/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/binary-operator-05/ast.snap
@@ -22,6 +22,7 @@ Some(Chunk(
             end: 1,
           ),
           name: Atom("x"),
+          reference: None,
         )),
         rhs: BinaryOperator(BinaryOperator(
           kind: LessThan(Span(
diff --git a/crates/fuse-parser/tests/cases/pass/binary-operator-06/ast.snap b/crates/fuse-parser/tests/cases/pass/binary-operator-06/ast.snap
index 6a8bacf..24571c9 100644
--- a/crates/fuse-parser/tests/cases/pass/binary-operator-06/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/binary-operator-06/ast.snap
@@ -22,6 +22,7 @@ Some(Chunk(
             end: 1,
           ),
           name: Atom("x"),
+          reference: None,
         )),
         rhs: BinaryOperator(BinaryOperator(
           kind: LogicalAnd(Span(
@@ -39,6 +40,7 @@ Some(Chunk(
                 end: 5,
               ),
               name: Atom("x"),
+              reference: None,
             )),
             rhs: Identifier(Identifier(
               span: Span(
@@ -46,6 +48,7 @@ Some(Chunk(
                 end: 11,
               ),
               name: Atom("max"),
+              reference: None,
             )),
           )),
           rhs: BinaryOperator(BinaryOperator(
@@ -59,6 +62,7 @@ Some(Chunk(
                 end: 17,
               ),
               name: Atom("x"),
+              reference: None,
             )),
             rhs: Identifier(Identifier(
               span: Span(
@@ -66,6 +70,7 @@ Some(Chunk(
                 end: 24,
               ),
               name: Atom("min"),
+              reference: None,
             )),
           )),
         )),
diff --git a/crates/fuse-parser/tests/cases/pass/binary-operator-07/ast.snap b/crates/fuse-parser/tests/cases/pass/binary-operator-07/ast.snap
index b3db450..8b26f40 100644
--- a/crates/fuse-parser/tests/cases/pass/binary-operator-07/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/binary-operator-07/ast.snap
@@ -22,6 +22,7 @@ Some(Chunk(
             end: 1,
           ),
           name: Atom("x"),
+          reference: None,
         )),
         rhs: BinaryOperator(BinaryOperator(
           kind: Multiply(Span(
@@ -39,6 +40,7 @@ Some(Chunk(
                 end: 6,
               ),
               name: Atom("x"),
+              reference: None,
             )),
           )),
           rhs: NumberLiteral(NumberLiteral(
diff --git a/crates/fuse-parser/tests/cases/pass/call-expression-01/ast.snap b/crates/fuse-parser/tests/cases/pass/call-expression-01/ast.snap
index 9609dda..52d42dd 100644
--- a/crates/fuse-parser/tests/cases/pass/call-expression-01/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/call-expression-01/ast.snap
@@ -22,6 +22,7 @@ Some(Chunk(
             end: 4,
           ),
           name: Atom("test"),
+          reference: None,
         )),
         arguments: [],
       ))),
diff --git a/crates/fuse-parser/tests/cases/pass/call-expression-02/ast.snap b/crates/fuse-parser/tests/cases/pass/call-expression-02/ast.snap
index 5a28fff..6cf9e64 100644
--- a/crates/fuse-parser/tests/cases/pass/call-expression-02/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/call-expression-02/ast.snap
@@ -22,6 +22,7 @@ Some(Chunk(
             end: 4,
           ),
           name: Atom("test"),
+          reference: None,
         )),
         arguments: [
           Identifier(Identifier(
@@ -30,6 +31,7 @@ Some(Chunk(
               end: 6,
             ),
             name: Atom("a"),
+            reference: None,
           )),
           Identifier(Identifier(
             span: Span(
@@ -37,6 +39,7 @@ Some(Chunk(
               end: 9,
             ),
             name: Atom("b"),
+            reference: None,
           )),
           Identifier(Identifier(
             span: Span(
@@ -44,6 +47,7 @@ Some(Chunk(
               end: 12,
             ),
             name: Atom("c"),
+            reference: None,
           )),
         ],
       ))),
diff --git a/crates/fuse-parser/tests/cases/pass/call-expression-03/ast.snap b/crates/fuse-parser/tests/cases/pass/call-expression-03/ast.snap
index 107b2fd..0392db2 100644
--- a/crates/fuse-parser/tests/cases/pass/call-expression-03/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/call-expression-03/ast.snap
@@ -22,6 +22,7 @@ Some(Chunk(
             end: 3,
           ),
           name: Atom("foo"),
+          reference: None,
         )),
         rhs: BinaryOperator(BinaryOperator(
           kind: Member(Span(
@@ -39,6 +40,7 @@ Some(Chunk(
                 end: 7,
               ),
               name: Atom("bar"),
+              reference: None,
             )),
             arguments: [],
           )),
@@ -53,6 +55,7 @@ Some(Chunk(
                 end: 13,
               ),
               name: Atom("baz"),
+              reference: None,
             )),
             arguments: [],
           )),
diff --git a/crates/fuse-parser/tests/cases/pass/enum-declaration-01/ast.snap b/crates/fuse-parser/tests/cases/pass/enum-declaration-01/ast.snap
index 9d2219a..c75c02d 100644
--- a/crates/fuse-parser/tests/cases/pass/enum-declaration-01/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/enum-declaration-01/ast.snap
@@ -22,6 +22,7 @@ Some(Chunk(
             end: 13,
           ),
           name: Atom("EnumName"),
+          reference: None,
         ),
         variants: [
           EnumVariant(
@@ -31,6 +32,7 @@ Some(Chunk(
                 end: 23,
               ),
               name: Atom("VariantA"),
+              reference: None,
             ),
             value: None,
           ),
@@ -41,6 +43,7 @@ Some(Chunk(
                 end: 33,
               ),
               name: Atom("VariantB"),
+              reference: None,
             ),
             value: None,
           ),
diff --git a/crates/fuse-parser/tests/cases/pass/enum-declaration-02/ast.snap b/crates/fuse-parser/tests/cases/pass/enum-declaration-02/ast.snap
index e555339..909eb30 100644
--- a/crates/fuse-parser/tests/cases/pass/enum-declaration-02/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/enum-declaration-02/ast.snap
@@ -22,6 +22,7 @@ Some(Chunk(
             end: 10,
           ),
           name: Atom("Ident"),
+          reference: None,
         ),
         variants: [
           EnumVariant(
@@ -31,6 +32,7 @@ Some(Chunk(
                 end: 16,
               ),
               name: Atom("Var1"),
+              reference: None,
             ),
             value: Some(StringLiteral(StringLiteral(
               span: Span(
@@ -52,6 +54,7 @@ Some(Chunk(
                 end: 32,
               ),
               name: Atom("Var2"),
+              reference: None,
             ),
             value: Some(StringLiteral(StringLiteral(
               span: Span(
diff --git a/crates/fuse-parser/tests/cases/pass/function-declaration-01/ast.snap b/crates/fuse-parser/tests/cases/pass/function-declaration-01/ast.snap
index e2ca866..4e1ac50 100644
--- a/crates/fuse-parser/tests/cases/pass/function-declaration-01/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/function-declaration-01/ast.snap
@@ -27,6 +27,7 @@ Some(Chunk(
               end: 13,
             ),
             name: Atom("test"),
+            reference: None,
           )),
           params: FunctionParameters(
             span: Span(
diff --git a/crates/fuse-parser/tests/cases/pass/function-declaration-02/ast.snap b/crates/fuse-parser/tests/cases/pass/function-declaration-02/ast.snap
index 4ed87ef..594ed56 100644
--- a/crates/fuse-parser/tests/cases/pass/function-declaration-02/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/function-declaration-02/ast.snap
@@ -27,6 +27,7 @@ Some(Chunk(
               end: 13,
             ),
             name: Atom("test"),
+            reference: None,
           )),
           params: FunctionParameters(
             span: Span(
@@ -51,6 +52,7 @@ Some(Chunk(
                         end: 15,
                       ),
                       name: Atom("a"),
+                      reference: None,
                     ),
                     mutable: false,
                   )),
@@ -75,6 +77,7 @@ Some(Chunk(
                         end: 18,
                       ),
                       name: Atom("b"),
+                      reference: None,
                     ),
                     mutable: false,
                   )),
@@ -99,6 +102,7 @@ Some(Chunk(
                         end: 21,
                       ),
                       name: Atom("c"),
+                      reference: None,
                     ),
                     mutable: false,
                   )),
@@ -119,6 +123,7 @@ Some(Chunk(
                 end: 26,
               ),
               name: Atom("b"),
+              reference: None,
             ))),
           ],
         )),
diff --git a/crates/fuse-parser/tests/cases/pass/function-declaration-03/ast.snap b/crates/fuse-parser/tests/cases/pass/function-declaration-03/ast.snap
index b75d41a..fa3772a 100644
--- a/crates/fuse-parser/tests/cases/pass/function-declaration-03/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/function-declaration-03/ast.snap
@@ -27,6 +27,7 @@ Some(Chunk(
               end: 7,
             ),
             name: Atom("test"),
+            reference: None,
           )),
           params: FunctionParameters(
             span: Span(
@@ -51,6 +52,7 @@ Some(Chunk(
                         end: 9,
                       ),
                       name: Atom("a"),
+                      reference: None,
                     ),
                     mutable: false,
                   )),
@@ -69,6 +71,7 @@ Some(Chunk(
             end: 15,
           ),
           name: Atom("a"),
+          reference: None,
         ))),
       )),
     ],
diff --git a/crates/fuse-parser/tests/cases/pass/function-expression-03/ast.snap b/crates/fuse-parser/tests/cases/pass/function-expression-03/ast.snap
index b00455b..ea345f8 100644
--- a/crates/fuse-parser/tests/cases/pass/function-expression-03/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/function-expression-03/ast.snap
@@ -45,6 +45,7 @@ Some(Chunk(
                         end: 4,
                       ),
                       name: Atom("a"),
+                      reference: None,
                     ),
                     mutable: false,
                   )),
@@ -69,6 +70,7 @@ Some(Chunk(
                         end: 7,
                       ),
                       name: Atom("b"),
+                      reference: None,
                     ),
                     mutable: false,
                   )),
@@ -89,6 +91,7 @@ Some(Chunk(
                 end: 11,
               ),
               name: Atom("a"),
+              reference: None,
             ))),
           ],
         )),
diff --git a/crates/fuse-parser/tests/cases/pass/function-expression-04/ast.snap b/crates/fuse-parser/tests/cases/pass/function-expression-04/ast.snap
index 69df94b..c93489f 100644
--- a/crates/fuse-parser/tests/cases/pass/function-expression-04/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/function-expression-04/ast.snap
@@ -38,6 +38,7 @@ Some(Chunk(
             end: 13,
           ),
           name: Atom("ident"),
+          reference: None,
         ))),
       ))),
     ],
diff --git a/crates/fuse-parser/tests/cases/pass/function-expression-05/ast.snap b/crates/fuse-parser/tests/cases/pass/function-expression-05/ast.snap
index 3a1b158..16dc855 100644
--- a/crates/fuse-parser/tests/cases/pass/function-expression-05/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/function-expression-05/ast.snap
@@ -45,6 +45,7 @@ Some(Chunk(
                         end: 8,
                       ),
                       name: Atom("value"),
+                      reference: None,
                     ),
                     mutable: false,
                   )),
@@ -63,6 +64,7 @@ Some(Chunk(
             end: 19,
           ),
           name: Atom("value"),
+          reference: None,
         ))),
       ))),
     ],
diff --git a/crates/fuse-parser/tests/cases/pass/identifier-01/ast.snap b/crates/fuse-parser/tests/cases/pass/identifier-01/ast.snap
index ded6437..559eaf5 100644
--- a/crates/fuse-parser/tests/cases/pass/identifier-01/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/identifier-01/ast.snap
@@ -17,6 +17,7 @@ Some(Chunk(
           end: 10,
         ),
         name: Atom("ident_name"),
+        reference: None,
       ))),
     ],
   ),
diff --git a/crates/fuse-parser/tests/cases/pass/if-expression-01/ast.snap b/crates/fuse-parser/tests/cases/pass/if-expression-01/ast.snap
index 817db7d..26dfd32 100644
--- a/crates/fuse-parser/tests/cases/pass/if-expression-01/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/if-expression-01/ast.snap
@@ -22,6 +22,7 @@ Some(Chunk(
             end: 7,
           ),
           name: Atom("expr"),
+          reference: None,
         )),
         body: Block(
           statements: [
diff --git a/crates/fuse-parser/tests/cases/pass/if-expression-02/ast.snap b/crates/fuse-parser/tests/cases/pass/if-expression-02/ast.snap
index c8f2e8d..40236ca 100644
--- a/crates/fuse-parser/tests/cases/pass/if-expression-02/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/if-expression-02/ast.snap
@@ -22,6 +22,7 @@ Some(Chunk(
             end: 7,
           ),
           name: Atom("cond"),
+          reference: None,
         )),
         body: Block(
           statements: [
diff --git a/crates/fuse-parser/tests/cases/pass/if-expression-03/ast.snap b/crates/fuse-parser/tests/cases/pass/if-expression-03/ast.snap
index d528cc9..b097d26 100644
--- a/crates/fuse-parser/tests/cases/pass/if-expression-03/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/if-expression-03/ast.snap
@@ -21,6 +21,7 @@ Some(Chunk(
             end: 8,
           ),
           name: Atom("cond1"),
+          reference: None,
         )),
         body: Block(
           statements: [
@@ -49,6 +50,7 @@ Some(Chunk(
               end: 38,
             ),
             name: Atom("cond2"),
+            reference: None,
           )),
           body: Block(
             statements: [
diff --git a/crates/fuse-parser/tests/cases/pass/if-expression-04/ast.snap b/crates/fuse-parser/tests/cases/pass/if-expression-04/ast.snap
index 82c7a23..ba7bc9d 100644
--- a/crates/fuse-parser/tests/cases/pass/if-expression-04/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/if-expression-04/ast.snap
@@ -26,6 +26,7 @@ Some(Chunk(
               end: 4,
             ),
             name: Atom("x"),
+            reference: None,
           )),
           rhs: BinaryOperator(BinaryOperator(
             kind: LogicalAnd(Span(
@@ -38,6 +39,7 @@ Some(Chunk(
                 end: 9,
               ),
               name: Atom("y"),
+              reference: None,
             )),
             rhs: Identifier(Identifier(
               span: Span(
@@ -45,6 +47,7 @@ Some(Chunk(
                 end: 15,
               ),
               name: Atom("z"),
+              reference: None,
             )),
           )),
         )),
@@ -82,6 +85,7 @@ Some(Chunk(
                   end: 35,
                 ),
                 name: Atom("x"),
+                reference: None,
               )),
               rhs: Identifier(Identifier(
                 span: Span(
@@ -89,6 +93,7 @@ Some(Chunk(
                   end: 41,
                 ),
                 name: Atom("y"),
+                reference: None,
               )),
             )),
             rhs: Identifier(Identifier(
@@ -97,6 +102,7 @@ Some(Chunk(
                 end: 46,
               ),
               name: Atom("z"),
+              reference: None,
             )),
           )),
           body: Block(
diff --git a/crates/fuse-parser/tests/cases/pass/impl-statement-01/ast.snap b/crates/fuse-parser/tests/cases/pass/impl-statement-01/ast.snap
index c3b0934..0e30dd7 100644
--- a/crates/fuse-parser/tests/cases/pass/impl-statement-01/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/impl-statement-01/ast.snap
@@ -23,6 +23,7 @@ Some(Chunk(
               end: 19,
             ),
             name: Atom("Test"),
+            reference: None,
           ),
         ),
         trait: TypeAnnotation(
@@ -32,6 +33,7 @@ Some(Chunk(
               end: 10,
             ),
             name: Atom("Trait"),
+            reference: None,
           ),
         ),
         methods: [],
diff --git a/crates/fuse-parser/tests/cases/pass/impl-statement-02/ast.snap b/crates/fuse-parser/tests/cases/pass/impl-statement-02/ast.snap
index 796272f..6e2378e 100644
--- a/crates/fuse-parser/tests/cases/pass/impl-statement-02/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/impl-statement-02/ast.snap
@@ -22,6 +22,7 @@ Some(Chunk(
               end: 19,
             ),
             name: Atom("Test"),
+            reference: None,
           ),
         ),
         trait: TypeAnnotation(
@@ -31,6 +32,7 @@ Some(Chunk(
               end: 10,
             ),
             name: Atom("Trait"),
+            reference: None,
           ),
         ),
         methods: [
@@ -52,6 +54,7 @@ Some(Chunk(
                     end: 28,
                   ),
                   name: Atom("test"),
+                  reference: None,
                 )),
                 params: FunctionParameters(
                   span: Span(
@@ -86,6 +89,7 @@ Some(Chunk(
                     end: 46,
                   ),
                   name: Atom("test2"),
+                  reference: None,
                 )),
                 params: FunctionParameters(
                   span: Span(
@@ -110,6 +114,7 @@ Some(Chunk(
                               end: 50,
                             ),
                             name: Atom("foo"),
+                            reference: None,
                           ),
                           mutable: false,
                         )),
@@ -120,6 +125,7 @@ Some(Chunk(
                               end: 58,
                             ),
                             name: Atom("number"),
+                            reference: None,
                           ),
                         )),
                         optional: false,
@@ -142,6 +148,7 @@ Some(Chunk(
                               end: 63,
                             ),
                             name: Atom("bar"),
+                            reference: None,
                           ),
                           mutable: false,
                         )),
@@ -152,6 +159,7 @@ Some(Chunk(
                               end: 71,
                             ),
                             name: Atom("number"),
+                            reference: None,
                           ),
                         )),
                         optional: false,
@@ -167,6 +175,7 @@ Some(Chunk(
                       end: 80,
                     ),
                     name: Atom("Type"),
+                    reference: None,
                   ),
                 )),
               ),
diff --git a/crates/fuse-parser/tests/cases/pass/parenthesized-expression-02/ast.snap b/crates/fuse-parser/tests/cases/pass/parenthesized-expression-02/ast.snap
index 795cbec..871f604 100644
--- a/crates/fuse-parser/tests/cases/pass/parenthesized-expression-02/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/parenthesized-expression-02/ast.snap
@@ -22,6 +22,7 @@ Some(Chunk(
             end: 11,
           ),
           name: Atom("identifier"),
+          reference: None,
         )),
       ))),
     ],
diff --git a/crates/fuse-parser/tests/cases/pass/parenthesized-expression-03/ast.snap b/crates/fuse-parser/tests/cases/pass/parenthesized-expression-03/ast.snap
index 9020163..9f9ecfe 100644
--- a/crates/fuse-parser/tests/cases/pass/parenthesized-expression-03/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/parenthesized-expression-03/ast.snap
@@ -65,6 +65,7 @@ Some(Chunk(
                 end: 27,
               ),
               name: Atom("other"),
+              reference: None,
             )),
           )),
         )),
diff --git a/crates/fuse-parser/tests/cases/pass/string-interpolation-03/ast.snap b/crates/fuse-parser/tests/cases/pass/string-interpolation-03/ast.snap
index 7afbef5..2fa1394 100644
--- a/crates/fuse-parser/tests/cases/pass/string-interpolation-03/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/string-interpolation-03/ast.snap
@@ -24,6 +24,7 @@ Some(Chunk(
                 end: 15,
               ),
               name: Atom("world"),
+              reference: None,
             )),
             format: Display,
           )),
diff --git a/crates/fuse-parser/tests/cases/pass/struct-construction-01/ast.snap b/crates/fuse-parser/tests/cases/pass/struct-construction-01/ast.snap
index 5fa4634..54df914 100644
--- a/crates/fuse-parser/tests/cases/pass/struct-construction-01/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/struct-construction-01/ast.snap
@@ -18,6 +18,7 @@ Some(Chunk(
             end: 8,
           ),
           name: Atom("MyStruct"),
+          reference: None,
         )),
         construction: ConstructionExpression(
           span: Span(
@@ -36,6 +37,7 @@ Some(Chunk(
                   end: 16,
                 ),
                 name: Atom("first"),
+                reference: None,
               ),
               value: NumberLiteral(NumberLiteral(
                 span: Span(
@@ -58,6 +60,7 @@ Some(Chunk(
                   end: 29,
                 ),
                 name: Atom("second"),
+                reference: None,
               ),
               value: NumberLiteral(NumberLiteral(
                 span: Span(
diff --git a/crates/fuse-parser/tests/cases/pass/struct-construction-02/ast.snap b/crates/fuse-parser/tests/cases/pass/struct-construction-02/ast.snap
index 69c0e8a..097f8b3 100644
--- a/crates/fuse-parser/tests/cases/pass/struct-construction-02/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/struct-construction-02/ast.snap
@@ -18,6 +18,7 @@ Some(Chunk(
             end: 4,
           ),
           name: Atom("Test"),
+          reference: None,
         )),
         construction: ConstructionExpression(
           span: Span(
@@ -36,6 +37,7 @@ Some(Chunk(
                   end: 12,
                 ),
                 name: Atom("first"),
+                reference: None,
               ),
               value: StringLiteral(StringLiteral(
                 span: Span(
@@ -56,6 +58,7 @@ Some(Chunk(
                 end: 29,
               ),
               name: Atom("second"),
+              reference: None,
             ))),
             Spread(SpreadArgument(
               span: Span(
@@ -68,6 +71,7 @@ Some(Chunk(
                   end: 39,
                 ),
                 name: Atom("third"),
+                reference: None,
               )),
             )),
           ],
diff --git a/crates/fuse-parser/tests/cases/pass/struct-declaration-01/ast.snap b/crates/fuse-parser/tests/cases/pass/struct-declaration-01/ast.snap
index 872af67..cb5160e 100644
--- a/crates/fuse-parser/tests/cases/pass/struct-declaration-01/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/struct-declaration-01/ast.snap
@@ -22,6 +22,7 @@ Some(Chunk(
             end: 15,
           ),
           name: Atom("MyStruct"),
+          reference: None,
         ),
         fields: [
           StructField(
@@ -32,6 +33,7 @@ Some(Chunk(
                 end: 23,
               ),
               name: Atom("field1"),
+              reference: None,
             ),
             type_annotation: TypeAnnotation(
               identifier: Identifier(
@@ -40,6 +42,7 @@ Some(Chunk(
                   end: 31,
                 ),
                 name: Atom("number"),
+                reference: None,
               ),
             ),
           ),
@@ -51,6 +54,7 @@ Some(Chunk(
                 end: 39,
               ),
               name: Atom("field2"),
+              reference: None,
             ),
             type_annotation: TypeAnnotation(
               identifier: Identifier(
@@ -59,6 +63,7 @@ Some(Chunk(
                   end: 47,
                 ),
                 name: Atom("string"),
+                reference: None,
               ),
             ),
           ),
@@ -70,6 +75,7 @@ Some(Chunk(
                 end: 55,
               ),
               name: Atom("field3"),
+              reference: None,
             ),
             type_annotation: TypeAnnotation(
               identifier: Identifier(
@@ -78,6 +84,7 @@ Some(Chunk(
                   end: 64,
                 ),
                 name: Atom("boolean"),
+                reference: None,
               ),
             ),
           ),
diff --git a/crates/fuse-parser/tests/cases/pass/tuple-initializer-03/ast.snap b/crates/fuse-parser/tests/cases/pass/tuple-initializer-03/ast.snap
index 24e7866..53051e4 100644
--- a/crates/fuse-parser/tests/cases/pass/tuple-initializer-03/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/tuple-initializer-03/ast.snap
@@ -23,6 +23,7 @@ Some(Chunk(
               end: 6,
             ),
             name: Atom("first"),
+            reference: None,
           ))),
         ],
       ))),
diff --git a/crates/fuse-parser/tests/cases/pass/variable-assignment-01/ast.snap b/crates/fuse-parser/tests/cases/pass/variable-assignment-01/ast.snap
index 31a453f..baf81cc 100644
--- a/crates/fuse-parser/tests/cases/pass/variable-assignment-01/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/variable-assignment-01/ast.snap
@@ -22,6 +22,7 @@ Some(Chunk(
             end: 1,
           ),
           name: Atom("x"),
+          reference: None,
         )),
         rhs: NumberLiteral(NumberLiteral(
           span: Span(
diff --git a/crates/fuse-parser/tests/cases/pass/variable-declaration-01/ast.snap b/crates/fuse-parser/tests/cases/pass/variable-declaration-01/ast.snap
index 0038f9c..82eef1b 100644
--- a/crates/fuse-parser/tests/cases/pass/variable-declaration-01/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/variable-declaration-01/ast.snap
@@ -29,6 +29,7 @@ Some(Chunk(
                 end: 6,
               ),
               name: Atom("id"),
+              reference: None,
             ),
             mutable: false,
           )),
diff --git a/crates/fuse-parser/tests/cases/pass/variable-declaration-02/ast.snap b/crates/fuse-parser/tests/cases/pass/variable-declaration-02/ast.snap
index 3a609c7..78c68af 100644
--- a/crates/fuse-parser/tests/cases/pass/variable-declaration-02/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/variable-declaration-02/ast.snap
@@ -29,6 +29,7 @@ Some(Chunk(
                 end: 6,
               ),
               name: Atom("id"),
+              reference: None,
             ),
             mutable: false,
           )),
diff --git a/crates/fuse-parser/tests/cases/pass/variable-declaration-03/ast.snap b/crates/fuse-parser/tests/cases/pass/variable-declaration-03/ast.snap
index b99d1c7..af1da23 100644
--- a/crates/fuse-parser/tests/cases/pass/variable-declaration-03/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/variable-declaration-03/ast.snap
@@ -29,6 +29,7 @@ Some(Chunk(
                 end: 11,
               ),
               name: Atom("num"),
+              reference: None,
             ),
             mutable: true,
           )),
diff --git a/crates/fuse-parser/tests/cases/pass/variable-declaration-04/ast.snap b/crates/fuse-parser/tests/cases/pass/variable-declaration-04/ast.snap
index b55cb9d..c7f3f5b 100644
--- a/crates/fuse-parser/tests/cases/pass/variable-declaration-04/ast.snap
+++ b/crates/fuse-parser/tests/cases/pass/variable-declaration-04/ast.snap
@@ -29,6 +29,7 @@ Some(Chunk(
                 end: 8,
               ),
               name: Atom("PI"),
+              reference: None,
             ),
             mutable: false,
           )),