feat(query) add declaration field to VarRef (#774)

crates/oxc_query/src/edges.rs

@@ -3504,6 +3504,7 @@ pub(super) fn resolve_var_ref_edge<'a, 'b: 'a>(
 ) -> ContextOutcomeIterator<'a, Vertex<'b>, VertexIterator<'a, Vertex<'b>>> {
     match edge_name {
         "span" => var_ref::span(contexts, resolve_info),
+        "declaration" => var_ref::declaration(contexts, resolve_info, adapter),
         "ancestor" => ancestors(contexts, adapter),
         "parent" => parents(contexts, adapter),
         "strip_parens" => strip_parens(contexts, parameters),
@@ -3515,11 +3516,35 @@ pub(super) fn resolve_var_ref_edge<'a, 'b: 'a>(
 
 mod var_ref {
     use trustfall::provider::{
-        ContextIterator, ContextOutcomeIterator, ResolveEdgeInfo, VertexIterator,
+        resolve_neighbors_with, ContextIterator, ContextOutcomeIterator, ResolveEdgeInfo,
+        VertexIterator,
     };
 
+    use crate::Adapter;
+
     use super::{super::vertex::Vertex, get_span};
 
+    pub(super) fn declaration<'a, 'b: 'a>(
+        contexts: ContextIterator<'a, Vertex<'b>>,
+        _resolve_info: &ResolveEdgeInfo,
+        adapter: &'a Adapter<'b>,
+    ) -> ContextOutcomeIterator<'a, Vertex<'b>, VertexIterator<'a, Vertex<'b>>> {
+        resolve_neighbors_with(contexts, |v| {
+            let var_ref = v
+                .as_var_ref()
+                .unwrap_or_else(|| panic!("expected to have a varref vertex, instead have: {v:#?}"))
+                .identifier_reference;
+            let v = var_ref
+                .reference_id
+                .get()
+                .and_then(|x| adapter.semantic.symbols().references.get(x))
+                .and_then(oxc_semantic::Reference::symbol_id)
+                .map(|x| adapter.semantic.symbol_declaration(x));
+
+            Box::new(v.into_iter().map(|x| (*x).into()))
+        })
+    }
+
     pub(super) fn span<'a, 'b: 'a>(
         contexts: ContextIterator<'a, Vertex<'b>>,
         _resolve_info: &ResolveEdgeInfo,

crates/oxc_query/src/schema.graphql

@@ -823,6 +823,7 @@ type FnDeclarationAST implements Function & ASTNode & FnDeclaration & HasSpan &
 
 interface VarRef implements HasSpan & Expression {
   name: String!
+  declaration: ASTNode
   # Expression
   as_constant_string: String
   """
@@ -835,6 +836,7 @@ interface VarRef implements HasSpan & Expression {
 
 type VarRefAST implements HasSpan & Expression & VarRef & ASTNode {
   name: String!
+  declaration: ASTNode
   # ASTNode
   parent: ASTNode
   ancestor: [ASTNode!]!