diff --git a/crates/prometeu-compiler/src/analysis/symbols/mod.rs b/crates/prometeu-compiler/src/analysis/symbols/mod.rs
index d77083ce..21d646c6 100644
--- a/crates/prometeu-compiler/src/analysis/symbols/mod.rs
+++ b/crates/prometeu-compiler/src/analysis/symbols/mod.rs
@@ -1,5 +1,6 @@
 use crate::common::diagnostics::{Diagnostic, DiagnosticLevel};
 use crate::common::spans::Span;
+use crate::frontends::pbs::ast::{AstArena, NodeId};
 use prometeu_analysis::NameId;
 use serde::{Deserialize, Serialize};
 use std::collections::HashMap;
@@ -52,11 +53,16 @@ pub struct DefIndex {
     symbols: HashMap<DefKey, SymbolId>,
 }
 
-#[derive(Debug, Default, Clone)]
+#[derive(Debug, Default, Clone, Serialize, Deserialize)]
 pub struct RefIndex {
     refs: Vec<Vec<Span>>,
 }
 
+#[derive(Debug, Default, Clone, Serialize, Deserialize)]
+pub struct NodeToSymbol {
+    map: Vec<Option<SymbolId>>,
+}
+
 impl SymbolArena {
     pub fn new() -> Self {
         Self { symbols: Vec::new() }
@@ -125,6 +131,32 @@ impl RefIndex {
     }
 }
 
+impl NodeToSymbol {
+    pub fn new() -> Self {
+        Self { map: Vec::new() }
+    }
+
+    pub fn bind_node(&mut self, node_id: NodeId, symbol_id: SymbolId) {
+        self.ensure(node_id);
+        self.map[node_id.0 as usize] = Some(symbol_id);
+    }
+
+    pub fn get(&self, node_id: NodeId) -> Option<SymbolId> {
+        self.map.get(node_id.0 as usize).and_then(|opt| *opt)
+    }
+
+    pub fn ensure(&mut self, node_id: NodeId) {
+        let index = node_id.0 as usize;
+        if index >= self.map.len() {
+            self.map.resize(index + 1, None);
+        }
+    }
+
+    pub fn resize_to_fit(&mut self, arena: &AstArena) {
+        self.map.resize(arena.nodes.len(), None);
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -212,4 +244,26 @@ mod tests {
         assert_eq!(index.refs_of(SymbolId(5)), &[span_b1]);
         assert!(index.refs_of(SymbolId(9)).is_empty());
     }
+
+    #[test]
+    fn node_to_symbol_bind_and_get() {
+        let mut map = NodeToSymbol::new();
+        let nid = NodeId(10);
+        let sid = SymbolId(5);
+
+        map.bind_node(nid, sid);
+        assert_eq!(map.get(nid), Some(sid));
+        assert_eq!(map.get(NodeId(0)), None);
+    }
+
+    #[test]
+    fn node_to_symbol_expands_automatically() {
+        let mut map = NodeToSymbol::new();
+        let nid_high = NodeId(100);
+        let sid = SymbolId(1);
+
+        map.bind_node(nid_high, sid);
+        assert_eq!(map.get(nid_high), Some(sid));
+        assert!(map.map.len() > 100);
+    }
 }
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