Tag a self dot method call with its receiver's syntactic type

Detect when a member call's receiver is literally self (a distinct
tree sitter node type, not an identifier) and, when the enclosing
impl block's bare type name is known, carry it on the raw_call as
rust_self_type. Nothing consumes this yet, so the extracted edges
are unchanged; it is the signal the next commit's resolver needs.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

graphify/extractors/rust.py

@@ -410,7 +410,7 @@ def extract_rust(path: Path) -> dict:
     seen_call_pairs: set[tuple[str, str]] = set()
     raw_calls: list[dict] = []
 
-    def walk_calls(node, caller_nid: str) -> None:
+    def walk_calls(node, caller_nid: str, self_type: str | None = None) -> None:
         if node.type == "function_item":
             return
         if node.type == "call_expression":
@@ -418,6 +418,7 @@ def extract_rust(path: Path) -> dict:
             callee_name: str | None = None
             is_member_call: bool = False
             is_scoped_call: bool = False
+            is_self_call: bool = False
             if func_node:
                 if func_node.type == "identifier":
                     callee_name = _read_text(func_node, source)
@@ -426,6 +427,9 @@ def extract_rust(path: Path) -> dict:
                     field = func_node.child_by_field_name("field")
                     if field:
                         callee_name = _read_text(field, source)
+                    receiver = func_node.child_by_field_name("value")
+                    if receiver is not None and receiver.type == "self":
+                        is_self_call = True
                 elif func_node.type == "scoped_identifier":
                     # Type::method() — still allow in-file EXTRACTED match, but
                     # skip cross-file resolution: bare last-segment lookup ignores
@@ -452,18 +456,21 @@ def extract_rust(path: Path) -> dict:
                             "weight": 1.0,
                         })
                 elif not is_scoped_call and callee_name.lower() not in _RUST_TRAIT_METHOD_BLOCKLIST:
-                    raw_calls.append({
+                    rc_entry = {
                         "caller_nid": caller_nid,
                         "callee": callee_name,
                         "is_member_call": is_member_call,
                         "source_file": str_path,
                         "source_location": f"L{node.start_point[0] + 1}",
-                    })
+                    }
+                    if is_self_call and self_type:
+                        rc_entry["rust_self_type"] = self_type
+                    raw_calls.append(rc_entry)
         for child in node.children:
-            walk_calls(child, caller_nid)
+            walk_calls(child, caller_nid, self_type)
 
-    for caller_nid, body_node, _impl_type in function_bodies:
-        walk_calls(body_node, caller_nid)
+    for caller_nid, body_node, impl_type in function_bodies:
+        walk_calls(body_node, caller_nid, impl_type)
 
     valid_ids = seen_ids
     clean_edges = []