diff --git a/torch/_inductor/pattern_matcher.py b/torch/_inductor/pattern_matcher.py
index 4b8a9abec6a..1cef108a3eb 100644
--- a/torch/_inductor/pattern_matcher.py
+++ b/torch/_inductor/pattern_matcher.py
@@ -1749,8 +1749,7 @@ def is_mutation_op(node: torch.fx.Node) -> bool:
         if _mutation_op_re.search(node.target.__name__):
             return True
     elif node.op == "call_method":
-        assert isinstance(node.target, str)
-        if _mutation_op_re.search(node.target):
+        if _mutation_op_re.search(cast(str, node.target)):
             return True
     return node.kwargs.get("out") is not None
 
@@ -1834,8 +1833,7 @@ class PatternMatcherPass:
         if has_call_module:
             nodes.append(graph.find_nodes(op="call_module", sort=False))
         pass_name = self.pass_name if self.pass_name is not None else "pattern_matcher"
-        assert isinstance(gm, torch.fx.GraphModule)
-        with GraphTransformObserver(gm, pass_name):
+        with GraphTransformObserver(cast(torch.fx.GraphModule, gm), pass_name):
             for node in sorted(itertools.chain.from_iterable(nodes), reverse=True):
                 target = extract_target(node)
                 if node.op == "call_module":
@@ -2160,6 +2158,5 @@ def extract_target(node: torch.fx.Node) -> torch.fx.node.Target:
      as a function.
     """
     if node.op == "call_module":
-        assert isinstance(node.target, str)
-        return _get_attr(node.graph.owning_module, node.target).__class__
+        return _get_attr(node.graph.owning_module, cast(str, node.target)).__class__
     return node.target