From 0f137f3e4bf16f8de2bd5c113092e8cee0b4d072 Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Thu, 18 Jun 2026 16:48:57 +0000
Subject: [PATCH] =?UTF-8?q?=E2=9A=A1=20Bolt:=20Use=20list.append=20instead?=
 =?UTF-8?q?=20of=20yield=20from=20in=20iter=5Fcalls=5Fin=5Ffunction=5Fbody?=
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Co-authored-by: tachyon-beep <544926+tachyon-beep@users.noreply.github.com>
---
 .jules/bolt.md                         |  3 +++
 src/wardline/scanner/ast_primitives.py | 32 +++++++++++++++-----------
 2 files changed, 22 insertions(+), 13 deletions(-)
 create mode 100644 .jules/bolt.md

diff --git a/.jules/bolt.md b/.jules/bolt.md
new file mode 100644
index 00000000..278f0212
--- /dev/null
+++ b/.jules/bolt.md
@@ -0,0 +1,3 @@
+## 2024-06-18 - AST Traversal Performance
+**Learning:** For hot-path AST traversal, eager list-appending (`list.append()`) is consistently faster than `yield from` recursion.
+**Action:** Use list-appending instead of `yield from` for AST traversal to improve performance.
diff --git a/src/wardline/scanner/ast_primitives.py b/src/wardline/scanner/ast_primitives.py
index 70f565b3..6a092e8b 100644
--- a/src/wardline/scanner/ast_primitives.py
+++ b/src/wardline/scanner/ast_primitives.py
@@ -105,38 +105,44 @@ def iter_calls_in_function_body(
     values, base classes, metaclass keywords) are still attributed to ``node``.
     """
 
-    def walk_node(current: ast.AST) -> Iterator[ast.Call]:
+    # Optimization: Eager list appending is significantly faster than recursive 'yield from'
+    # in CPython due to reduced generator delegation overhead on deep AST paths.
+    result: list[ast.Call] = []
+
+    def walk_node(current: ast.AST) -> None:
         if isinstance(current, (ast.FunctionDef, ast.AsyncFunctionDef)):
             for decorator in current.decorator_list:
-                yield from walk_node(decorator)
-            yield from _walk_argument_defaults(current.args)
+                walk_node(decorator)
+            _walk_argument_defaults(current.args)
             return
         if isinstance(current, ast.ClassDef):
             for decorator in current.decorator_list:
-                yield from walk_node(decorator)
+                walk_node(decorator)
             for base in current.bases:
-                yield from walk_node(base)
+                walk_node(base)
             for keyword in current.keywords:
-                yield from walk_node(keyword.value)
+                walk_node(keyword.value)
             return
         if isinstance(current, ast.Lambda):
-            yield from _walk_argument_defaults(current.args)
+            _walk_argument_defaults(current.args)
             return
         if isinstance(current, ast.Call):
-            yield current
+            result.append(current)
         for child in ast.iter_child_nodes(current):
-            yield from walk_node(child)
+            walk_node(child)
 
-    def _walk_argument_defaults(args: ast.arguments) -> Iterator[ast.Call]:
+    def _walk_argument_defaults(args: ast.arguments) -> None:
         for default in args.defaults:
-            yield from walk_node(default)
+            walk_node(default)
         for kw_default in args.kw_defaults:
             if kw_default is None:
                 continue
-            yield from walk_node(kw_default)
+            walk_node(kw_default)
 
     for stmt in node.body:
-        yield from walk_node(stmt)
+        walk_node(stmt)
+
+    return iter(result)
 
 
 def resolve_self_method_fqn(