fix(rust): emit field type references for tuple structs

extract_rust() only traversed field_declaration_list (named-struct
bodies), so tuple structs -- whose positional fields nest under
ordered_field_declaration_list -- had every field type reference
silently dropped from the graph.

This is the same node shape the enum handler already accounts for
(tuple variants nest their types under ordered_field_declaration_list);
the struct path was simply left behind. Add an additive branch that,
for each type node in a tuple struct's ordered_field_declaration_list,
collects type refs via _rust_collect_type_refs and emits references
edges with the appropriate field / generic_arg context. The
named-struct path is untouched.

For `struct Wrapper(Logger, Config);` with Logger/Config defined
in-file, no field edges were produced before; both are now emitted.

Adds test_rust_tuple_struct_field_references and a tuple struct to the
shared Rust fixture covering plain and generic positional field types.

graphify/extract.py

@@ -8180,6 +8180,27 @@ def extract_rust(path: Path) -> dict:
                                 if tgt != item_nid:
                                     add_edge(item_nid, tgt, "references",
                                              field.start_point[0] + 1, context=ctx)
+                    # Tuple structs (`struct Wrapper(pub Logger, Config);`) nest their
+                    # positional field types directly under ordered_field_declaration_list
+                    # with no field_declaration wrapper -- the same shape handled for tuple
+                    # enum variants below. Without this branch these field type references
+                    # are silently dropped.
+                    for c in node.children:
+                        if c.type != "ordered_field_declaration_list":
+                            continue
+                        fline = c.start_point[0] + 1
+                        for tc in c.children:
+                            if tc.type not in ("type_identifier", "generic_type",
+                                               "scoped_type_identifier", "reference_type",
+                                               "primitive_type", "tuple_type", "array_type"):
+                                continue
+                            refs = []
+                            _rust_collect_type_refs(tc, source, False, refs)
+                            for ref_name, role in refs:
+                                ctx = "generic_arg" if role == "generic_arg" else "field"
+                                tgt = ensure_named_node(ref_name, fline)
+                                if tgt != item_nid:
+                                    add_edge(item_nid, tgt, "references", fline, context=ctx)
                 if t == "enum_item":
                     # Variant payload types nest under enum_variant_list ->
                     # enum_variant -> ordered_field_declaration_list (tuple variant,

tests/fixtures/sample.rs

@@ -56,3 +56,5 @@ enum GraphEvent {
     NodeAdded(Graph),
     Processed { proc: DataProcessor },
 }
+
+struct GraphPair(Graph, Result<DataProcessor>);

tests/test_multilang.py

@@ -365,6 +365,19 @@ def test_rust_struct_field_emits_field_context():
     assert ("DataProcessor", "DataProcessor") not in _edge_labels(r, "references", "field")
 
 
+def test_rust_tuple_struct_field_references():
+    """Tuple struct fields (`struct Wrapper(A, B);`) nest their positional types
+    under ordered_field_declaration_list with no field_declaration wrapper -- the
+    same shape as tuple enum variants. That path was not traversed for structs, so
+    tuple-struct field type references were silently dropped.
+    """
+    r = extract_rust(FIXTURES / "sample.rs")
+    field_refs = _edge_labels(r, "references", "field")
+    assert ("GraphPair", "Graph") in field_refs, "tuple-struct field reference missing"
+    assert ("GraphPair", "Result") in field_refs, "tuple-struct generic field reference missing"
+    assert ("GraphPair", "DataProcessor") in _edge_labels(r, "references", "generic_arg")
+
+
 def test_rust_method_parameter_return_and_generic_contexts():
     r = extract_rust(FIXTURES / "sample.rs")
     assert ("build", "DataProcessor") in _edge_labels(r, "references", "parameter_type")