"""
Built-in function and type variable tracking for TorchDynamo's symbolic execution.

This module contains variable tracker classes for Python built-in functions, types,
and operations during graph compilation. It handles symbolic execution of:

- Built-in functions (len, getattr, isinstance, etc.)
- Type constructors (int, float, str, list, dict, etc.)
- Built-in operators and methods
- Special Python constructs (super, hasattr, etc.)

Key classes:
- BuiltinVariable: Tracks built-in functions and handles their execution
- TypeVariable: Manages type constructor calls and type checking
- SuperVariable: Handles super() calls in class hierarchies

These variable trackers ensure that built-in Python operations are correctly
handled during symbolic execution, either by executing them directly when safe
or by creating appropriate graph nodes when needed.
"""

import abc
import ast
import builtins
import contextlib
import functools
import inspect
import itertools
import logging
import math
import operator
import sys
import types
import typing
from collections import defaultdict, OrderedDict
from collections.abc import Callable, Iterable, Sequence
from typing import Any, NoReturn, TYPE_CHECKING

import torch
from torch.overrides import BaseTorchFunctionMode
from torch.utils._python_dispatch import is_traceable_wrapper_subclass

from .. import graph_break_hints, polyfills, variables
from ..exc import (
    handle_observed_exception,
    ObservedAttributeError,
    ObservedTypeError,
    ObservedUserStopIteration,
    raise_observed_exception,
    raise_type_error,
    raise_value_error,
    unimplemented,
    Unsupported,
    UserError,
    UserErrorType,
)
from ..guards import GuardBuilder, install_guard
from ..source import (
    AttrSource,
    GetItemSource,
    GlobalSource,
    is_constant_source,
    LocalSource,
    Source,
    TypeSource,
)
from ..utils import (
    check_constant_args,
    check_numpy_ndarray_args,
    check_unspec_or_constant_args,
    check_unspec_python_args,
    dict_methods,
    extract_fake_example_value,
    get_fake_value,
    is_tensor_getset_descriptor,
    istype,
    numpy_operator_wrapper,
    proxy_args_kwargs,
    raise_args_mismatch,
    str_methods,
    tensortype_to_dtype,
    unpack_iterable,
)
from .base import (
    AsPythonConstantNotImplementedError,
    GetSet,
    Member,
    ValueMutationNew,
    VariableTracker,
)
from .constant import ConstantVariable, FakeIdVariable
from .dicts import (
    ConstDictVariable,
    DictItemsVariable,
    DictKeysVariable,
    DictViewVariable,
    OrderedDictVariable,
)
from .hashable import is_hashable
from .lists import BaseListVariable, ListVariable, TupleIteratorVariable, TupleVariable
from .misc import CellVariable, NullVariable, StringFormatVariable
from .object_protocol import (
    _NO_DEFAULT,
    binary_iop,
    binary_op,
    generic_delitem,
    generic_getattr,
    generic_getitem,
    generic_getiter,
    generic_hash,
    generic_is_true,
    generic_issubclass,
    generic_repr,
    generic_richcompare,
    generic_setitem,
    generic_size,
    generic_str,
    maybe_get_python_type,
    pycallable_check,
    pyiter_check,
    pylong_from_base,
    pynumber_absolute,
    pynumber_add,
    pynumber_float,
    pynumber_index,
    pynumber_inplace_add,
    pynumber_inplace_matrix_multiply,
    pynumber_inplace_multiply,
    pynumber_int,
    pynumber_invert,
    pynumber_matrix_multiply,
    pynumber_multiply,
    pynumber_negative,
    pynumber_positive,
    pynumber_tobase,
    pysequence_check,
    pysequence_contains,
    python_constant_richcompare_impl,
    ternary_iop,
    ternary_op,
    type_implements_mp_length,
    type_implements_sq_length,
    vt_identity_compare,
)
from .sets import FrozensetVariable, SetVariable
from .tensor import (
    FakeItemVariable,
    supported_comparison_ops,
    SymNodeVariable,
    TensorVariable,
    UnspecializedPythonVariable,
)
from .user_defined import UserDefinedObjectVariable, UserDefinedVariable


if TYPE_CHECKING:
    # Cyclic dependency...
    from torch._dynamo.codegen import PyCodegen
    from torch._dynamo.symbolic_convert import InstructionTranslatorBase

log = logging.getLogger(__name__)


IN_PLACE_DESUGARING_MAP = {
    operator.iadd: operator.add,
    operator.isub: operator.sub,
    operator.imul: operator.mul,
    operator.ifloordiv: operator.floordiv,
    operator.itruediv: operator.truediv,
    operator.imod: operator.mod,
    operator.imatmul: operator.imatmul,
    operator.ilshift: operator.lshift,
    operator.irshift: operator.rshift,
    operator.ipow: operator.pow,
    operator.iand: operator.and_,
    operator.ior: operator.or_,
    operator.ixor: operator.xor,
}

_BUILTIN_CONSTANT_FOLDABLE_METHODS: dict[type, frozenset[str]] = {
    int: frozenset({"__new__", "from_bytes"}),
    bool: frozenset({"__new__", "from_bytes"}),
    float: frozenset({"fromhex", "hex"}),
}
if sys.version_info >= (3, 14):
    _BUILTIN_CONSTANT_FOLDABLE_METHODS[complex] = frozenset({"from_number"})


_HandlerCallback = Callable[
    ["InstructionTranslatorBase", typing.Any, typing.Any], VariableTracker | None
]
_TrackersType = type[VariableTracker] | tuple[type[VariableTracker], ...]
_OPERATOR_TO_DUNDER: dict[Callable[..., Any], str] = {
    operator.eq: "__eq__",
    operator.ne: "__ne__",
    operator.lt: "__lt__",
    operator.le: "__le__",
    operator.gt: "__gt__",
    operator.ge: "__ge__",
}


bin_ops = (
    operator.pow,
    operator.mul,
    operator.matmul,
    operator.floordiv,
    operator.truediv,
    operator.mod,
    operator.add,
    operator.lt,
    operator.gt,
    operator.ge,
    operator.le,
    operator.ne,
    operator.eq,
    operator.sub,
    operator.ipow,
    operator.imul,
    operator.imatmul,
    operator.ifloordiv,
    operator.itruediv,
    operator.imod,
    operator.iadd,
    operator.isub,
)

bin_int_ops = (
    operator.and_,
    operator.or_,
    operator.xor,
    operator.iand,
    operator.ixor,
    operator.ior,
)

un_int_ops = (operator.invert,)

tensor_and_int_ops = (
    operator.lshift,
    operator.rshift,
    operator.ilshift,
    operator.irshift,
    operator.getitem,
)

un_ops = (
    operator.abs,
    operator.pos,
    operator.neg,
    operator.not_,  # Note: this has a local scalar dense call
    operator.length_hint,
)

_SET_LIKE_OP_SUPPORT: tuple[type[VariableTracker], ...] = (
    DictItemsVariable,
    DictKeysVariable,
    SetVariable,
    UserDefinedObjectVariable,
)

BUILTIN_TO_TENSOR_FN_MAP: dict[Callable[..., Any], Callable[..., Any]] = {}

# These functions represent the r* versions of the above ops
# Basically, if __add__(1, Tensor) is called, it is translated
# to __radd__(Tensor, 1).
# In the builtin var, we check if there is a tensor in the first args position,
# if not, we swap the args and use the r* version of the op.
BUILTIN_TO_TENSOR_RFN_MAP: dict[Callable[..., Any], Callable[..., Any]] = {}

# Sentinel for `inspect.getattr_static` lookups that must distinguish
# "attribute absent" from "attribute is None" (e.g. `__reversed__ = None`
# opt-out).
_MISSING_SENTINEL = object()

_COMPUTED_LAZY_CONSTANT_OPS: frozenset[Callable[..., Any]] = frozenset(
    [
        operator.add,
        operator.sub,
        operator.mul,
    ]
)


def _try_computed_lazy_constant(
    fn: Callable[..., Any], args: list[VariableTracker]
) -> VariableTracker | None:
    """Build a ComputedLazyConstantVariable for fn(*args), or None to fall back."""
    from .lazy import ComputedLazyConstantVariable, LazyConstantVariable

    fn = IN_PLACE_DESUGARING_MAP.get(fn, fn)
    if fn not in _COMPUTED_LAZY_CONSTANT_OPS or len(args) != 2:
        return None
    any_unrealized = False
    for arg in args:
        if (
            isinstance(arg, (LazyConstantVariable, ComputedLazyConstantVariable))
            and not arg.is_realized()
        ):
            any_unrealized = True
        elif not isinstance(arg, ConstantVariable):
            return None
    if not any_unrealized:
        return None
    return ComputedLazyConstantVariable.create(fn, args)


def populate_builtin_to_tensor_fn_map() -> None:
    global BUILTIN_TO_TENSOR_FN_MAP
    if len(BUILTIN_TO_TENSOR_FN_MAP) > 0:
        # Only populate once; after there are elements present no need to
        # repopulate
        return
    most_recent_func: Callable[..., Any] | None = None

    class GetMethodMode(BaseTorchFunctionMode):
        """
        Mode to extract the correct methods from torch function invocations
        (Used to get the correct torch.Tensor methods from builtins)
        """

        def __torch_function__(
            self,
            func: Callable[..., Any],
            types: Any,
            args: Sequence[Any] = (),
            kwargs: dict[str, Any] | None = None,
        ) -> Any:
            kwargs = kwargs or {}
            nonlocal most_recent_func
            most_recent_func = func
            return func(*args, **kwargs)

    inp0 = torch.ones(1)
    inp1 = torch.ones(1)
    inp0_int = torch.ones(1, dtype=torch.int32)
    inp1_int = torch.ones(1, dtype=torch.int32)
    with GetMethodMode():
        setups_and_oplists: list[tuple[Callable[..., Any], Iterable[Any]]] = [
            (lambda o: o(inp0), un_ops),
            (lambda o: o(inp0_int), un_int_ops),
            (lambda o: o(inp0, inp1), bin_ops),
            (lambda o: o(inp0_int, inp1_int), bin_int_ops),
            (lambda o: o(inp0_int, 0), tensor_and_int_ops),
        ]
        for setup_fn, op_list in setups_and_oplists:
            for op in op_list:
                setup_fn(op)
                if most_recent_func is None:
                    raise AssertionError(
                        f"most_recent_func is None after setup for op {op}"
                    )
                BUILTIN_TO_TENSOR_FN_MAP[op] = most_recent_func

        # gather the reverse functions
        rsetups_and_oplists: list[tuple[Callable[..., Any], Iterable[Any]]] = [
            (
                lambda o: o(1, inp1),
                bin_ops,
            ),  # Get r* ops, (ex. __sub__(int, Tensor) -> __rsub__(Tensor, int))
            (lambda o: o(1, inp1_int), bin_int_ops),
            (lambda o: o(0, inp0_int), tensor_and_int_ops),
        ]

        rskips = {operator.matmul, operator.imatmul, operator.getitem}
        for setup_fn, op_list in rsetups_and_oplists:
            for op in op_list:
                if op in rskips:
                    continue
                setup_fn(op)
                if most_recent_func is None:
                    raise AssertionError(
                        f"most_recent_func is None after setup for reverse op {op}"
                    )
                if most_recent_func != BUILTIN_TO_TENSOR_FN_MAP[op]:
                    BUILTIN_TO_TENSOR_RFN_MAP[op] = most_recent_func


class BaseBuiltinVariable(VariableTracker):
    """
    Common base class for all builtin variable trackers (BuiltinVariable,
    DictBuiltinVariable, IterBuiltinVariable, and future specialized builtins).

    Provides shared implementations for guard installation, hasattr tracing,
    and Python-level hashability/equality.

    Specialized subclasses (e.g. DictBuiltinVariable) set `_fn` as a class
    attribute. BuiltinVariable stores the callable on the instance as `self.fn`
    and overrides as_python_constant / reconstruct / tp_getattro_impl accordingly.
    """

    _fn: Any = None

    # Type attribute readers shared by BaseBuiltinVariable and BuiltinVariable.
    # Each reader declines (returns None) when the wrapped callable is not a type,
    # letting getattro_impl fall through to its dynamic getattr handling.
    # CPython classification (Objects/typeobject.c):
    #   __bases__ -> type_getsets[] type_get_bases (getset)
    #   __base__  -> type_members[] {T_OBJECT, offsetof(tp_base), Py_READONLY}
    #   __flags__ -> type_members[] {T_ULONG, offsetof(tp_flags), Py_READONLY}
    def _type_get_bases(
        self: "BaseBuiltinVariable", tx: "InstructionTranslatorBase"
    ) -> "VariableTracker | None":
        fn = self.as_python_constant()
        if not isinstance(fn, type):
            return None
        source = self.source and AttrSource(self.source, "__bases__")
        items = [
            VariableTracker.build(tx, b, source and GetItemSource(source, i))
            for i, b in enumerate(fn.__bases__)
        ]
        return variables.TupleVariable(items, source=source)

    def _type_get_base(
        self: "BaseBuiltinVariable", tx: "InstructionTranslatorBase"
    ) -> "VariableTracker | None":
        fn = self.as_python_constant()
        if not isinstance(fn, type):
            return None
        source = self.source and AttrSource(self.source, "__base__")
        return VariableTracker.build(tx, fn.__base__, source)

    def _type_get_flags(
        self: "BaseBuiltinVariable", tx: "InstructionTranslatorBase"
    ) -> "VariableTracker | None":
        fn = self.as_python_constant()
        if not isinstance(fn, type):
            return None
        source = self.source and AttrSource(self.source, "__flags__")
        return VariableTracker.build(tx, fn.__flags__, source)

    tp_getset = {"__bases__": GetSet(_type_get_bases, None)}
    tp_members = {
        "__base__": Member(_type_get_base, None),
        "__flags__": Member(_type_get_flags, None),
    }

    @classmethod
    def create_with_source(cls, value: Any, source: Source) -> "BaseBuiltinVariable":
        install_guard(source.make_guard(GuardBuilder.BUILTIN_MATCH))
        return cls(source=source)

    def as_python_constant(self) -> Any:
        return self._fn

    def reconstruct(self, codegen: "PyCodegen") -> None:
        name = self.as_python_constant().__name__
        if name in codegen.tx.f_globals:
            raise AssertionError("shadowed global")
        codegen.append_output(codegen.create_load_global(name, add=True))

    def tp_getattro_impl(
        self, tx: "InstructionTranslatorBase", name: str
    ) -> VariableTracker:
        # Declarative type-attribute dispatch, mirroring the consultation at the
        # top of VariableTracker.getattro_impl. Inlined here because this
        # override keeps its own GetAttrVariable fallback instead of delegating
        # to super().
        fn = self.as_python_constant()
        source = self.source and AttrSource(self.source, name)
        attr = getattr(fn, name, None)
        return variables.GetAttrVariable(
            self, name, py_type=type(attr) if attr is not None else None, source=source
        )

    def call_obj_hasattr(
        self, tx: "InstructionTranslatorBase", name: str
    ) -> ConstantVariable:
        return VariableTracker.build(tx, hasattr(self.as_python_constant(), name))  # type: ignore[return-value]

    def hash_impl(self, tx: "InstructionTranslatorBase") -> tuple[int, bool]:
        # CPython meth_hash: https://github.com/python/cpython/blob/e76aa128fe/Objects/methodobject.c#L319
        return hash(self.as_python_constant()), False

    def tp_richcompare_impl(
        self,
        tx: "InstructionTranslatorBase",
        other: VariableTracker,
        op: str,
    ) -> VariableTracker:
        return python_constant_richcompare_impl(self, tx, other, op)

    def call_method(
        self,
        tx: "InstructionTranslatorBase",
        name: str,
        args: list[VariableTracker],
        kwargs: dict[str, VariableTracker],
    ) -> VariableTracker:
        if name == "__str__" and len(args) == 1 and not kwargs:
            arg = args[0]
            if self.as_python_constant() is object:
                return generic_repr(tx, arg)
            if self.as_python_constant() is type:
                if isinstance(arg, variables.UserDefinedClassVariable):
                    return VariableTracker.build(tx, type.__str__(arg.value))
                if arg.is_python_constant() and isinstance(
                    arg.as_python_constant(), type
                ):
                    return VariableTracker.build(
                        tx, type.__str__(arg.as_python_constant())
                    )
            return generic_str(tx, arg)
        if name == "__repr__" and len(args) == 1 and not kwargs:
            arg = args[0]
            if self.as_python_constant() is object and isinstance(
                arg, variables.UserDefinedObjectVariable
            ):
                return VariableTracker.build(tx, object.__repr__(arg.value))
            if self.as_python_constant() is type:
                if isinstance(arg, variables.UserDefinedClassVariable):
                    return VariableTracker.build(tx, type.__repr__(arg.value))
                if arg.is_python_constant() and isinstance(
                    arg.as_python_constant(), type
                ):
                    return VariableTracker.build(
                        tx, type.__repr__(arg.as_python_constant())
                    )
            return generic_repr(tx, arg)
        return super().call_method(tx, name, args, kwargs)


def _uses_custom_classinfo_check(
    type_info: Any,
    *,
    use_instancecheck: bool = True,
    use_subclasscheck: bool = True,
) -> bool:
    if isinstance(type_info, tuple):
        return any(_uses_custom_classinfo_check(item) for item in type_info)
    if isinstance(type_info, types.UnionType):
        return any(
            _uses_custom_classinfo_check(item) for item in typing.get_args(type_info)
        )
    if typing.get_origin(type_info) is typing.Union:
        typing_union_uses_instancecheck = sys.version_info >= (3, 12)
        return any(
            _uses_custom_classinfo_check(
                item,
                use_instancecheck=typing_union_uses_instancecheck,
                use_subclasscheck=True,
            )
            for item in typing.get_args(type_info)
        )
    if isinstance(type_info, type):
        if type_info in tensortype_to_dtype:
            return False

        type_info_meta = type(type_info)
        instancecheck = getattr(type_info_meta, "__instancecheck__", None)
        subclasscheck = getattr(type_info_meta, "__subclasscheck__", None)
        if (
            instancecheck is type.__instancecheck__
            and subclasscheck is type.__subclasscheck__
        ):
            return False

        if issubclass(type_info, torch.Tensor) and (
            type_info_meta.__module__,
            type_info_meta.__qualname__,
        ) in {
            ("torch.nn.parameter", "_ParameterMeta"),
            ("torch.nn.parameter", "_BufferMeta"),
            ("torch.distributed.fsdp._flat_param", "_FlatParameterMeta"),
        }:
            return False

        return (
            use_instancecheck
            and instancecheck is not type.__instancecheck__
            and instancecheck is not abc.ABCMeta.__instancecheck__
        ) or (
            use_subclasscheck
            and subclasscheck is not type.__subclasscheck__
            and subclasscheck is not abc.ABCMeta.__subclasscheck__
        )
    return False


class BuiltinVariable(BaseBuiltinVariable):
    """
    A VariableTracker that represents a built-in value (functions and operators).
    A lot of the code here assumes it will be a function object.

    The BuiltinVariable class wraps Python built-in functions (like len, isinstance, etc.)
    and operators (like +, -, *, etc.) to enable symbolic execution during tracing. This allows
    Dynamo to properly handle these operations when converting Python code to FX graphs while
    maintaining correct semantics and enabling optimizations.
    """

    _SENTINEL = object()
    _nonvar_fields = {
        "fn",
        *VariableTracker._nonvar_fields,
    }

    # __name__ -> type_getsets[] type_get_name (getset). Unlike the type-attribute
    # readers on BaseBuiltinVariable, BuiltinVariable exposes __name__ for any
    # wrapped callable (not just types), so it never declines.
    def _builtin_type_get_name(
        self: "BuiltinVariable", tx: "InstructionTranslatorBase"
    ) -> "VariableTracker | None":
        source = self.source and AttrSource(self.source, "__name__")
        return VariableTracker.build(tx, self.fn.__name__, source)

    tp_getset = {
        "__name__": GetSet(_builtin_type_get_name, None),
    }

    @classmethod
    def create_with_source(cls, value: Any, source: Source) -> "BuiltinVariable":
        install_guard(source.make_guard(GuardBuilder.BUILTIN_MATCH))
        return cls(value, source=source)

    @staticmethod
    @functools.cache
    def _constant_fold_functions() -> set[Callable[..., Any]]:
        fns: set[Callable[..., Any]] = {
            abs,
            all,
            any,
            ascii,
            bin,
            bool,
            callable,
            chr,
            complex,
            divmod,
            float,
            format,
            getattr,
            hex,
            int,
            len,
            max,
            min,
            oct,
            ord,
            pow,
            repr,
            round,
            str,
            str.format,
            sum,
            type,
            operator.abs,
            operator.pos,
            operator.neg,
            operator.not_,
            operator.truth,
            operator.invert,
            operator.pow,
            operator.mul,
            operator.matmul,
            operator.floordiv,
            operator.truediv,
            operator.mod,
            operator.add,
            operator.sub,
            operator.getitem,
            operator.length_hint,
            operator.lshift,
            operator.rshift,
            operator.and_,
            operator.or_,
            operator.xor,
            operator.ipow,
            operator.imul,
            operator.imatmul,
            operator.ifloordiv,
            operator.itruediv,
            operator.imod,
            operator.iadd,
            operator.isub,
            operator.ilshift,
            operator.irshift,
            operator.iand,
            operator.ixor,
            operator.ior,
            operator.index,
        }
        from .tensor import supported_comparison_ops

        fns.update(supported_comparison_ops.values())
        fns.update(x for x in math.__dict__.values() if isinstance(x, type(math.sqrt)))
        return fns

    def can_constant_fold_through(self) -> bool:
        return self.fn in self._constant_fold_functions()

    @staticmethod
    @functools.cache
    def _fx_graph_functions() -> set[Callable[..., Any]]:
        fns = {
            operator.abs,
            operator.pos,
            operator.neg,
            operator.not_,
            operator.invert,
            operator.pow,
            operator.mul,
            operator.matmul,
            operator.floordiv,
            operator.truediv,
            operator.mod,
            operator.add,
            operator.lt,
            operator.gt,
            operator.ge,
            operator.le,
            operator.ne,
            operator.eq,
            operator.sub,
            operator.length_hint,
            operator.lshift,
            operator.rshift,
            operator.and_,
            operator.or_,
            operator.xor,
            operator.ipow,
            operator.imul,
            operator.imatmul,
            operator.ifloordiv,
            operator.itruediv,
            operator.getitem,
            operator.imod,
            operator.iadd,
            operator.isub,
            operator.ilshift,
            operator.irshift,
            operator.iand,
            operator.ixor,
            operator.ior,
        }
        return fns  # type: ignore[return-value]

    @staticmethod
    @functools.cache
    def _binops() -> dict[
        Callable[..., object], tuple[list[str], Callable[..., object]]
    ]:
        # function -> ([forward name, reverse name, in-place name], in-place op)
        fns: dict[Callable[..., object], tuple[list[str], Callable[..., object]]] = {
            # NB: The follow binary operators are not supported for now, since the
            # corresponding magic methods aren't defined on SymInt / SymFloat:
            # operator.matmul
            # divmod
            # operator.and_
            # operator.or_
        }
        return fns

    @staticmethod
    @functools.cache
    def _binop_handlers() -> dict[
        Callable[..., object],
        list[
            tuple[
                tuple[
                    type[VariableTracker],
                    _TrackersType,
                ],
                _HandlerCallback,
            ]
        ],
    ]:
        # Multiple dispatch mechanism defining custom binop behavior for certain type
        # combinations. Handlers are attempted in order, and will be used if the type checks
        # match. They are expected to have the signature:
        # fn(tx, arg0: VariableTracker, arg1: VariableTracker) -> VariableTracker
        from .functions import BaseUserFunctionVariable
        from .nn_module import NNModuleVariable
        from .tensor import supported_const_comparison_ops
        from .torch import BaseTorchVariable

        # Override table contains: op_fn -> [list of handlers]
        op_handlers: dict[Any, list[Any]] = {}
        for (
            op,
            (magic_method_names, in_place_op),
        ) in BuiltinVariable._binops().items():
            op_handlers[op] = []
            op_handlers[in_place_op] = []

            forward_name, reverse_name, inplace_name = magic_method_names

            # User-defined args (highest precedence)
            def user_defined_handler(
                tx: "InstructionTranslatorBase",
                a: VariableTracker,
                b: VariableTracker,
                *,
                forward_name: str = forward_name,
                reverse_name: str = reverse_name,
            ) -> VariableTracker:
                # Manually handle reversing logic if needed (e.g. call __radd__)

                # TODO: If we expand this to handle tensor args, we need to manually
                # handle cases like this:
                #
                # class A(int):
                #     def __radd__(self, other):
                #         print("woof")
                # torch.randn(3) + A(3)
                #
                # In this example, A.__radd__() is not called -> nothing is printed, because
                # Tensor.__add__ only does a subtype test against int, ignoring the subclass.
                # To be fully correct, we should not call A.__radd__() here, and there may be
                # other cases to reason about and add exceptions for.
                if isinstance(a, UserDefinedVariable):
                    return a.call_method(tx, forward_name, [b], {})
                else:
                    return b.call_method(tx, reverse_name, [a], {})

            op_handlers[op].append(
                ((UserDefinedVariable, VariableTracker), user_defined_handler)
            )
            op_handlers[op].append(
                ((VariableTracker, UserDefinedVariable), user_defined_handler)
            )

            def user_defined_inplace_handler(
                tx: "InstructionTranslatorBase",
                a: VariableTracker,
                b: VariableTracker,
                *,
                forward_name: str = inplace_name,
            ) -> VariableTracker:
                return a.call_method(tx, forward_name, [b], {})

            op_handlers[in_place_op].append(
                ((UserDefinedVariable, VariableTracker), user_defined_inplace_handler)
            )
            op_handlers[in_place_op].append(
                ((VariableTracker, UserDefinedVariable), user_defined_inplace_handler)
            )

            # Dynamic shape args
            def dynamic_handler(
                tx: "InstructionTranslatorBase",
                a: VariableTracker,
                b: VariableTracker,
                *,
                fn: Callable[..., Any] = op,
            ) -> VariableTracker:
                from .builder import wrap_fx_proxy

                return wrap_fx_proxy(
                    tx,
                    tx.output.create_proxy(
                        "call_function", fn, *proxy_args_kwargs([a, b], {})
                    ),
                )

            op_handlers[op].append(
                ((SymNodeVariable, VariableTracker), dynamic_handler)
            )
            op_handlers[op].append(
                ((VariableTracker, SymNodeVariable), dynamic_handler)
            )

            # NB: Prefer out-of-place op when calling in-place op to generate valid graph
            op_handlers[in_place_op].append(
                ((SymNodeVariable, VariableTracker), dynamic_handler)
            )
            op_handlers[in_place_op].append(
                ((VariableTracker, SymNodeVariable), dynamic_handler)
            )

        # Special cases - lower precedence but still prefer these over constant folding

        def create_cmp_op_handlers(
            op: Callable[..., Any],
        ) -> list[tuple[tuple[_TrackersType, _TrackersType], _HandlerCallback]]:
            def compare_by_value(
                tx: "InstructionTranslatorBase", a: VariableTracker, b: VariableTracker
            ) -> VariableTracker:
                try:
                    return VariableTracker.build(tx, op(a.value, b.value))  # type: ignore[attr-defined]
                except TypeError as exc:
                    raise_observed_exception(
                        type(exc),
                        tx,
                        args=list(exc.args),
                    )

            result: list[
                tuple[
                    tuple[
                        _TrackersType,
                        _TrackersType,
                    ],
                    _HandlerCallback,
                ]
            ] = [((ConstantVariable, ConstantVariable), compare_by_value)]

            if op in _OPERATOR_TO_DUNDER:
                # For constants, speedup the comparison instead of going
                # through generic_richcompare. Removing this line causes
                # major regression for pr time benchmark - add_loop_eager.
                result = [
                    ((ConstantVariable, ConstantVariable), compare_by_value),
                ]

                op_var = BuiltinVariable(op)
                # Special handling of SymNode variable
                result.extend(
                    [
                        (
                            (SymNodeVariable, VariableTracker),
                            op_var._comparison_with_symnode,
                        ),
                        (
                            (VariableTracker, SymNodeVariable),
                            op_var._comparison_with_symnode,
                        ),
                    ]
                )

                # COMPARE_OP (a == b) dispatches through generic_richcompare,
                # which implements do_richcompare via tp_richcompare_impl slots.
                # See object_protocol.py for details.
                dunder = _OPERATOR_TO_DUNDER[op]

                def handler(
                    tx: "InstructionTranslatorBase",
                    a: VariableTracker,
                    b: VariableTracker,
                ) -> VariableTracker:
                    return generic_richcompare(tx, a, b, dunder)

                result.append(((VariableTracker, VariableTracker), handler))
                return result

            result = [((ConstantVariable, ConstantVariable), compare_by_value)]

            if op in supported_const_comparison_ops.values() and op.__name__.startswith(
                "is_"
            ):
                # Tensor is None, List is not None, etc
                none_result = op(object(), None)

                def never(
                    tx: "InstructionTranslatorBase",
                    a: VariableTracker,
                    b: VariableTracker,
                ) -> VariableTracker:
                    return VariableTracker.build(tx, none_result)

                obj_op_none = never
                none_op_obj = never

                types_that_are_never_none = (
                    TensorVariable,
                    SymNodeVariable,
                    NNModuleVariable,
                    BaseListVariable,
                    UserDefinedVariable,
                    BaseUserFunctionVariable,
                    ConstDictVariable,
                    BaseTorchVariable,
                )
                result.extend(
                    [
                        (
                            (types_that_are_never_none, ConstantVariable),
                            obj_op_none,
                        ),
                        (
                            (ConstantVariable, types_that_are_never_none),
                            none_op_obj,
                        ),
                    ]
                )

                op_var = BuiltinVariable(op)
                result.extend(
                    [
                        (
                            (TensorVariable, VariableTracker),
                            op_var._comparison_with_tensor,
                        ),
                        (
                            (VariableTracker, TensorVariable),
                            op_var._comparison_with_tensor,
                        ),
                        (
                            (SymNodeVariable, VariableTracker),
                            op_var._comparison_with_symnode,
                        ),
                        (
                            (VariableTracker, SymNodeVariable),
                            op_var._comparison_with_symnode,
                        ),
                    ]
                )

                def handle_is(
                    tx: "InstructionTranslatorBase",
                    left: VariableTracker,
                    right: VariableTracker,
                ) -> VariableTracker | None:
                    result = vt_identity_compare(left, right)
                    if result is None:
                        return None
                    is_same = result.as_python_constant()
                    return VariableTracker.build(
                        tx, is_same if op.__name__ == "is_" else not is_same
                    )

                result.append(((VariableTracker, VariableTracker), handle_is))  # type: ignore[arg-type]

            return result

        for op in supported_comparison_ops.values():
            if not callable(op):
                raise AssertionError(f"comparison op {op} is not callable")
            if op in op_handlers:
                raise AssertionError(f"duplicate handler for op {op}")
            op_handlers[op] = create_cmp_op_handlers(op)

        return op_handlers

    @staticmethod
    def _find_binop_handler(
        op: Callable[..., Any], a_type: type[VariableTracker], b_type: type
    ) -> list[_HandlerCallback] | None:
        handlers = BuiltinVariable._binop_handlers().get(op)
        if handlers is None:
            return None

        matches = []
        for (type1, type2), handler in handlers:
            if issubclass(a_type, type1) and issubclass(b_type, type2):
                matches.append(handler)
        return matches

    def can_insert_in_graph(self) -> bool:
        return self.fn in self._fx_graph_functions()

    # Builtins that have been promoted to their own VT classes. Creating a
    # BuiltinVariable for these is a bug; use the specialized class instead.
    MUST_USE_SPECIALIZED: frozenset[Any] = frozenset(
        {dict, getattr, hasattr, iter, list, setattr}
    )

    def __init__(self, fn: Any, **kwargs: Any) -> None:
        if fn in self.MUST_USE_SPECIALIZED:
            raise AssertionError(
                f"Use the specialized VT class for {fn!r}, not BuiltinVariable. "
                f"E.g. DictBuiltinVariable for dict."
            )
        super().__init__(**kwargs)
        self.fn = fn

    def __repr__(self) -> str:
        if self.fn is None:
            name = "None"
        else:
            name = self.fn.__name__

        return f"{self.__class__.__name__}({name})"

    def as_python_constant(self) -> Any:
        return self.fn

    def get_real_python_backed_value(self) -> Any:
        return self.fn

    def nb_or_impl(
        self,
        tx: "InstructionTranslatorBase",
        other: VariableTracker,
        reverse: bool = False,
    ) -> VariableTracker:
        # BuiltinVariable wraps built-in types like list, tuple, dict.
        # type(self.fn).__or__(self.fn, other_val) delegates to CPython's
        # _Py_union_type_or for type unions (e.g. list | tuple).
        # https://github.com/python/cpython/blob/v3.13.0/Objects/typeobject.c#L6028-L6030 (type_as_number.nb_or = _Py_union_type_or)
        # https://github.com/python/cpython/blob/3.13/Objects/unionobject.c#L162 (_Py_union_type_or)
        if not isinstance(self.fn, type):
            return VariableTracker.build(tx, NotImplemented)
        try:
            other_val = other.as_python_constant()
        except NotImplementedError:
            return VariableTracker.build(tx, NotImplemented)
        # pyrefly: ignore[bad-argument-count]
        result = type(self.fn).__or__(self.fn, other_val)
        if result is NotImplemented:
            return VariableTracker.build(tx, NotImplemented)
        return VariableTracker.build(tx, result)

    def as_proxy(self) -> Any:
        DTYPE = {
            bool: torch.bool,
            int: torch.int64,
            float: torch.float64,
        }
        if self.fn in DTYPE:
            return DTYPE[self.fn]
        return super().as_proxy()

    def reconstruct(self, codegen: "PyCodegen") -> None:
        name = self.fn.__name__
        if self.fn.__module__ != "builtins":
            raise AssertionError(f"Expected builtins module, got {self.fn.__module__}")
        if name in codegen.tx.f_globals:
            raise AssertionError("shadowed global")
        codegen.append_output(codegen.create_load_global(name, add=True))

    def constant_args(self, *args: VariableTracker, **kwargs: VariableTracker) -> bool:
        return check_constant_args(args, kwargs)

    def tensor_args(self, *args: VariableTracker) -> bool:
        any_tensor = False
        for arg in args:
            if isinstance(arg, variables.GetAttrVariable):
                return False
            any_tensor = any_tensor or arg.is_tensor()
        return any_tensor

    def tensor_args_type(self, arg_types: list[type]) -> bool:
        any_tensor = False
        for arg_type in arg_types:
            if issubclass(arg_type, variables.GetAttrVariable):
                return False
            any_tensor = any_tensor or issubclass(arg_type, variables.TensorVariable)
        return any_tensor

    def python_and_tensor_constant_only(
        self, *args: VariableTracker, **kwargs: VariableTracker
    ) -> bool:
        tensor_args = []
        non_tensor_args = []
        for i in itertools.chain(args, kwargs.values()):
            if i.is_tensor():
                tensor_args.append(i)
            else:
                non_tensor_args.append(i)
        return all(
            is_constant_source(t.source) if t.source is not None else False
            for t in tensor_args
        ) and self.constant_args(*non_tensor_args)

    @staticmethod
    def unwrap_unspec_args_kwargs(
        args: list[VariableTracker], kwargs: dict[str, VariableTracker]
    ) -> tuple[list[Any], dict[str, Any]]:
        return [x.as_python_constant() for x in args], {
            k: v.as_python_constant() for k, v in kwargs.items()
        }

    def has_constant_handler(
        self, args: list[VariableTracker], kwargs: dict[str, VariableTracker]
    ) -> bool:
        return self.can_constant_fold_through() and check_unspec_or_constant_args(
            args, kwargs
        )

    @staticmethod
    def _make_handler(
        fn: Callable[..., Any], arg_types: list[type], has_kwargs: bool
    ) -> Callable[
        [
            "InstructionTranslatorBase",
            list[VariableTracker],
            dict[str, VariableTracker],
        ],
        VariableTracker | None,
    ]:
        from .lazy import (
            ComputedLazyConstantVariable,
            LazyConstantVariable,
            LazyVariableTracker,
        )

        obj = BuiltinVariable(fn)
        handlers: list[_HandlerCallback] = []

        lazy_constant_types = (LazyConstantVariable, ComputedLazyConstantVariable)
        lazy_types = [t for t in arg_types if issubclass(t, LazyVariableTracker)]
        if lazy_types:
            if not all(issubclass(t, lazy_constant_types) for t in lazy_types):
                # Realize non-constant lazy args and re-dispatch.  Any
                # lazy constant args are kept and handled on the
                # second dispatch through the branch below.
                return lambda tx, args, kwargs: obj.call_function(
                    tx,
                    [
                        a.realize()
                        if isinstance(a, LazyVariableTracker)
                        and not isinstance(a, lazy_constant_types)
                        else a
                        for a in args
                    ],
                    kwargs,
                )

            # Only lazy constant types.  Install type guards
            # and resolve the dispatch type.  If the resolved type is
            # ConstantVariable (the common case), delegate to a handler
            # built for ConstantVariable.  Otherwise (e.g. specialize_int=
            # False turned the int into a SymNodeVariable), realize and
            # re-dispatch so the correct handler is used.
            inner_handler = BuiltinVariable._make_handler(
                fn,
                [
                    ConstantVariable if issubclass(t, lazy_constant_types) else t
                    for t in arg_types
                ],
                has_kwargs,
            )

            def lazy_constant_handler(
                tx: "InstructionTranslatorBase",
                args: list[VariableTracker],
                kwargs: dict[str, VariableTracker],
            ) -> VariableTracker | None:
                if not kwargs:
                    result = _try_computed_lazy_constant(fn, args)
                    if result is not None:
                        return result
                for a in args:
                    if isinstance(a, lazy_constant_types):
                        if a.get_handler_type_for_dispatch() is not ConstantVariable:
                            return obj.call_function(
                                tx,
                                [
                                    v.realize()
                                    if isinstance(v, lazy_constant_types)
                                    else v
                                    for v in args
                                ],
                                kwargs,
                            )
                return inner_handler(tx, args, kwargs)

            return lazy_constant_handler

        if inspect.isclass(fn) and (
            issubclass(fn, BaseException)
            # GeneratorExit doesn't inherit from Exception
            # >>> issubclass(GeneratorExit, Exception)
            # False
            or fn is GeneratorExit
        ):

            def create_exception_class_object(
                tx: "InstructionTranslatorBase",
                args: list[VariableTracker],
                kwargs: dict[str, VariableTracker],
            ) -> VariableTracker:
                if fn is AssertionError and not all(
                    x.is_python_constant() and isinstance(x.as_python_constant(), str)
                    for x in args
                ):
                    unimplemented(
                        gb_type="assert with non-string message",
                        context=str(args),
                        explanation="Dynamo only supports asserts with string messages",
                        hints=[*graph_break_hints.SUPPORTABLE],
                    )

                if fn is StopIteration:
                    return variables.StopIterationVariable(fn, args, kwargs)
                elif fn is AttributeError:
                    return variables.AttributeErrorVariable(fn, args, kwargs)
                elif fn is NameError:
                    return variables.NameErrorVariable(fn, args, kwargs)
                return variables.ExceptionVariable(fn, args, kwargs)

            return create_exception_class_object

        if obj.can_insert_in_graph() and not (
            fn is operator.getitem
            and (
                len(arg_types) != 2
                or not issubclass(arg_types[0], variables.TensorVariable)
            )
        ):
            if obj.tensor_args_type(arg_types):
                return obj._handle_insert_op_in_graph
            elif has_kwargs:
                # need runtime check for kwargs
                handlers.append(obj._handle_insert_op_in_graph)

        # Handle binary ops (e.g. __add__ / __radd__, __iadd__, etc.)
        # NB: Tensor args are handled above and not here
        if len(arg_types) == 2 and not has_kwargs:
            # Try to find a handler for the arg types; otherwise, fall through to constant handler
            binop_handlers = BuiltinVariable._find_binop_handler(fn, *arg_types)
            if not binop_handlers:
                pass
            elif len(binop_handlers) == 1:
                (binop_handler,) = binop_handlers
                handlers.append(lambda tx, args, _: binop_handler(tx, *args))
            else:

                def call_binop_handlers(
                    tx: "InstructionTranslatorBase", args: Any, _: Any
                ) -> Any:
                    # pyrefly: ignore [not-iterable]
                    for fn in binop_handlers:
                        rv = fn(tx, *args)
                        if rv:
                            return rv
                    return None

                handlers.append(call_binop_handlers)

        self_handler = getattr(obj, f"call_{fn.__name__}", None)
        if self_handler:

            def call_self_handler(
                tx: "InstructionTranslatorBase",
                args: list[VariableTracker],
                kwargs: dict[str, VariableTracker],
            ) -> VariableTracker | None:
                try:
                    # pyrefly: ignore [not-callable]
                    return self_handler(tx, *args, **kwargs)
                except TypeError:
                    # Check if binding is bad. inspect signature bind is expensive.
                    # So check only when handler call fails.
                    try:
                        # pyrefly: ignore [bad-argument-type]
                        inspect.signature(self_handler).bind(tx, *args, **kwargs)
                    except TypeError as e:
                        has_constant_handler = obj.has_constant_handler(args, kwargs)
                        if not has_constant_handler:
                            log.warning(
                                "incorrect arg count %s %s and no constant handler",
                                self_handler,
                                e,
                            )
                            unimplemented(
                                gb_type="invalid call to builtin op handler",
                                context=f"invalid args to {self_handler}: {args} {kwargs}",
                                explanation=f"Encountered TypeError when trying to handle op {fn.__name__}",
                                hints=[*graph_break_hints.DIFFICULT],
                            )
                    else:
                        raise
                except Unsupported as exc:
                    has_constant_handler = obj.has_constant_handler(args, kwargs)
                    if not has_constant_handler:
                        raise
                    # Actually, we will handle this just fine
                    exc.remove_from_stats()
                return None

            handlers.append(call_self_handler)

        if obj.can_constant_fold_through():
            if (
                all(issubclass(x, ConstantVariable) for x in arg_types)
                and not has_kwargs
            ):

                def constant_fold_handler(
                    tx: "InstructionTranslatorBase",
                    args: list[VariableTracker],
                    kwargs: dict[str, VariableTracker],
                ) -> VariableTracker | None:
                    # fast path
                    try:
                        res = fn(
                            *[x.as_python_constant() for x in args],
                        )
                    except Exception as exc:
                        raise_observed_exception(
                            type(exc),
                            tx,
                            args=list(exc.args),
                        )
                    except AsPythonConstantNotImplementedError as exc:
                        unimplemented(
                            gb_type="constant fold exception",
                            context=f"attempted to run function {fn} with arguments {args}",
                            explanation="Encountered exception when attempting to constant fold.",
                            hints=[*graph_break_hints.DYNAMO_BUG],
                            from_exc=exc,
                        )
                    return VariableTracker.build(tx, res)

            else:

                def constant_fold_handler(
                    tx: "InstructionTranslatorBase",
                    args: list[VariableTracker],
                    kwargs: dict[str, VariableTracker],
                ) -> VariableTracker | None:
                    # path with a runtime check
                    if check_unspec_or_constant_args(args, kwargs):
                        try:
                            res = fn(
                                *[x.as_python_constant() for x in args],
                                **{
                                    k: v.as_python_constant() for k, v in kwargs.items()
                                },
                            )
                        except AsPythonConstantNotImplementedError as exc:
                            unimplemented(
                                gb_type="constant fold exception",
                                context=f"attempted to run function {fn} with arguments {args}",
                                explanation="Encountered exception when attempting to constant fold.",
                                hints=[*graph_break_hints.DYNAMO_BUG],
                                from_exc=exc,
                            )
                        except Exception as exc:
                            raise_observed_exception(
                                type(exc),
                                tx,
                                args=list(exc.args),
                            )
                        return VariableTracker.build(tx, res)
                    return None

            handlers.append(constant_fold_handler)

        def call_unimplemented(args: list[VariableTracker]) -> None:
            real_arg_types = [arg.python_type_name() for arg in args]
            unimplemented(
                gb_type="Failed to trace builtin operator",
                context=f"builtin {fn.__name__} {arg_types} {has_kwargs}",
                explanation=f"Dynamo does not know how to trace builtin operator `{fn.__name__}` "
                f"with argument types {real_arg_types} (has_kwargs {has_kwargs})",
                hints=[
                    f"Avoid calling builtin `{fn.__name__}` with argument types {real_arg_types}. "
                    f"Consider using an equivalent alternative function/method to `{fn.__name__}`.",
                    "If you are attempting to call a logging function (e.g. `print`), "
                    "you can try adding it to `torch._dynamo.config.reorderable_logging_functions`.",
                    "Please report an issue to PyTorch.",
                ],
            )

        if len(handlers) == 0:
            return lambda tx, args, kwargs: call_unimplemented(args)
        elif len(handlers) == 1:
            (handler,) = handlers

            def builtin_dispatch(
                tx: "InstructionTranslatorBase",
                args: list[VariableTracker],
                kwargs: dict[str, VariableTracker],
            ) -> VariableTracker | None:
                rv = handler(tx, args, kwargs)
                if rv:
                    return rv
                call_unimplemented(args)
                return rv

        else:

            def builtin_dispatch(
                tx: "InstructionTranslatorBase",
                args: list[VariableTracker],
                kwargs: dict[str, VariableTracker],
            ) -> VariableTracker | None:
                rv = None
                for fn in handlers:
                    rv = fn(tx, args, kwargs)
                    if rv:
                        return rv
                call_unimplemented(args)
                return rv

        return builtin_dispatch

    @staticmethod
    def _constant_eval_numeric_expr(node: ast.AST) -> bool:
        allowed_nodes = (
            ast.Expression,
            ast.Constant,
            ast.UnaryOp,
            ast.BinOp,
            ast.UAdd,
            ast.USub,
            ast.Invert,
            ast.Add,
            ast.Sub,
            ast.Mult,
            ast.Div,
            ast.FloorDiv,
            ast.Mod,
            ast.BitOr,
            ast.BitXor,
            ast.BitAnd,
        )
        return all(
            isinstance(child, allowed_nodes)
            and (
                not isinstance(child, ast.Constant)
                or isinstance(child.value, (bool, int, float, complex))
            )
            for child in ast.walk(node)
        )

    @staticmethod
    def _constant_eval_result(
        tx: "InstructionTranslatorBase", tree: ast.Expression, filename: str
    ) -> VariableTracker | None:
        if any(isinstance(child, ast.Call) for child in ast.walk(tree)):
            return None
        ast.fix_missing_locations(tree)
        try:
            result = ast.literal_eval(tree)
        except ValueError:
            if not BuiltinVariable._constant_eval_numeric_expr(tree):
                return None
            try:
                result = eval(
                    compile(tree, filename, "eval"),
                    {"__builtins__": {}},
                    {},
                )
            except Exception as exc:
                raise_observed_exception(type(exc), tx, args=list(exc.args))
        return VariableTracker.build(tx, result)

    def call_eval(
        self,
        tx: "InstructionTranslatorBase",
        source: VariableTracker,
        *args: VariableTracker,
        **kwargs: VariableTracker,
    ) -> VariableTracker | None:
        if args or kwargs:
            return None
        if not source.is_python_constant():
            return None
        source_str = source.as_python_constant()
        if not isinstance(source_str, str):
            return None

        try:
            tree = ast.parse(source_str.strip(), mode="eval")
        except SyntaxError as exc:
            raise_observed_exception(SyntaxError, tx, args=[exc.msg])

        return self._constant_eval_result(tx, tree, "<torch._dynamo.eval>")

    def call_vars(
        self,
        tx: "InstructionTranslatorBase",
        *args: VariableTracker,
        **kwargs: VariableTracker,
    ) -> VariableTracker:
        if kwargs:
            raise_type_error(tx, "vars() takes no keyword arguments")
        if len(args) == 0:
            return self._call_frame_locals_snapshot(tx)
        if len(args) != 1:
            raise_type_error(tx, f"vars expected at most 1 argument, got {len(args)}")
        # vars(obj) is obj.__dict__ if __dict__ is present else TypeError
        try:
            return args[0].tp_getattro_impl(tx, "__dict__")
        except ObservedAttributeError:
            raise_observed_exception(TypeError, tx)

    def call_locals(
        self, tx: "InstructionTranslatorBase", *args: VariableTracker
    ) -> VariableTracker:
        if len(args) != 0:
            raise_observed_exception(TypeError, tx)
        return self._call_frame_locals_snapshot(tx)

    @staticmethod
    def _call_frame_locals_snapshot(tx: "InstructionTranslatorBase") -> VariableTracker:
        from .builder import VariableBuilder

        frame_local_names = set(tx.f_code.co_varnames) | set(tx.cell_and_freevars())
        cell_and_freevars = set(tx.cell_and_freevars())
        frame_locals = {}
        # symbolic_cellvars registers all of the frame's cells. Cells are listed first so that a colliding fast local of
        # the same name shadows the cell, matching CPython (except for 3.12, which is backwards): the two share a name
        # but not a localsplus slot, and the fast slot wins while it holds a value (an empty one is skipped below,
        # leaving the cell contents visible).
        if sys.version_info[:2] == (3, 12):
            its = (tx.symbolic_locals.items(), tx.symbolic_cellvars.items())
        else:
            its = (tx.symbolic_cellvars.items(), tx.symbolic_locals.items())

        for name, value in itertools.chain(*its):
            if name not in frame_local_names:
                continue
            # Match on CellVariable, not name: a colliding fast local shares a
            # cell's name but is not itself a cell.
            if type.__instancecheck__(CellVariable, value):
                value = tx.output.side_effects.load_cell(value)
            if type.__instancecheck__(NullVariable, value) or isinstance(
                value, variables.DeletedVariable
            ):
                continue
            frame_locals[ConstantVariable.create(name)] = value
        # Include locals pruned from symbolic_locals by the unused-input optimisation.
        # locals()/vars() observes the entire namespace, so build VTs (installing
        # guards) for any pruned entry that still has a runtime value.
        for name in frame_local_names:
            if name in frame_locals or name in cell_and_freevars:
                continue
            if name not in tx.f_locals:
                continue
            vt = VariableBuilder(tx, LocalSource(name))(tx.f_locals[name])
            frame_locals[ConstantVariable.create(name)] = vt
        return ConstDictVariable(
            frame_locals,
            mutation_type=ValueMutationNew(),
        )

    def _handle_insert_op_in_graph(
        self,
        tx: "InstructionTranslatorBase",
        args: list[VariableTracker],
        kwargs: dict[str, VariableTracker],
    ) -> VariableTracker | None:
        from .builder import wrap_fx_proxy, wrap_fx_proxy_cls

        if kwargs and not self.tensor_args(*args, *kwargs.values()):
            return None

        # insert handling for torch function here
        from .builder import SourcelessBuilder
        from .torch_function import can_dispatch_torch_function, dispatch_torch_function

        global BUILTIN_TO_TENSOR_RFN_MAP, BUILTIN_TO_TENSOR_FN_MAP
        if can_dispatch_torch_function(tx, args, kwargs):
            # Only remap the fn to tensor methods if we aren't exporting
            # export serde does not handle method descriptors today
            if not tx.export:
                # Ensure the builtin maps are populated before accessing them
                populate_builtin_to_tensor_fn_map()
                # Use sourceless builder, we built the map ourselves
                if not args[0].is_tensor():
                    if self.fn in BUILTIN_TO_TENSOR_RFN_MAP:
                        func = BUILTIN_TO_TENSOR_RFN_MAP[self.fn]
                    else:
                        func = BUILTIN_TO_TENSOR_FN_MAP[self.fn]

                    tmp = args[0]
                    # swap args and call reverse version of func
                    args[0] = args[1]  # type: ignore[index]
                    args[1] = tmp  # type: ignore[index]
                else:
                    func = BUILTIN_TO_TENSOR_FN_MAP[self.fn]
            else:
                func = self.fn

            fn_var = SourcelessBuilder.create(tx, func)

            return dispatch_torch_function(tx, fn_var, args, kwargs)

        fn = self.fn
        try:
            # Constant fold for constant tensor and python constants
            if self.python_and_tensor_constant_only(*args, **kwargs):
                from ..bytecode_transformation import unique_id
                from .functions import invoke_and_store_as_constant

                return invoke_and_store_as_constant(
                    tx, fn, unique_id(fn.__name__), args, kwargs
                )

            if fn in IN_PLACE_DESUGARING_MAP and isinstance(
                args[0], variables.ConstantVariable
            ):
                # In-place operators like += usually mustate tensor
                # values, but in the edge case of immutable values they
                # re-bind the variable.
                #
                # The easiest way to keep the graph consistent in this
                # scenario is to de-sugar eagerly.
                fn = IN_PLACE_DESUGARING_MAP[fn]
                args = [args[0], args[1]]  # type: ignore[assignment]

            if fn is operator.getitem:
                if kwargs:
                    raise_type_error(
                        tx, "_operator.getitem() takes no keyword arguments"
                    )
                if len(args) != 2:
                    raise_type_error(
                        tx, f"getitem expected 2 arguments, got {len(args)}"
                    )
                if isinstance(args[1], SymNodeVariable):
                    # Standard indexing will force specialization due to
                    # __index__.  Rewrite as a regular torch op which will
                    # trace fine
                    fn = torch.select
                    args = [
                        args[0],
                        variables.VariableTracker.build(tx, 0),
                        args[1],
                    ]  # type: ignore[assignment]

            # Interaction between ndarray and tensors:
            #   We prefer the tensor op whenever there are tensors involved
            # NB: Use exact type check here - NumpyNdarrayVariable is a TensorVariable
            # subclass but should NOT trigger the tensor path
            if check_numpy_ndarray_args(args, kwargs) and not any(
                type(arg) is TensorVariable for arg in args
            ):
                proxy = tx.output.create_proxy(
                    "call_function",
                    numpy_operator_wrapper(fn),
                    *proxy_args_kwargs(args, kwargs),
                )

                return wrap_fx_proxy_cls(variables.NumpyNdarrayVariable, tx, proxy)

            if (
                fn in _OPERATOR_TO_DUNDER
                and len(args) == 2
                and any(
                    not isinstance(a, (variables.TensorVariable, SymNodeVariable))
                    for a in args
                )
            ):
                return generic_richcompare(
                    tx, args[0], args[1], _OPERATOR_TO_DUNDER[fn]
                )

            proxy = tx.output.create_proxy(
                "call_function",
                fn,
                *proxy_args_kwargs(args, kwargs),
            )
            if any(isinstance(arg, FakeItemVariable) for arg in args):
                return wrap_fx_proxy_cls(
                    FakeItemVariable,
                    tx,
                    proxy,
                )
            elif check_unspec_python_args(args, kwargs):
                _args, _kwargs = self.unwrap_unspec_args_kwargs(args, kwargs)
                raw_value = fn(*_args, **_kwargs)

                need_unwrap = any(
                    x.need_unwrap
                    for x in itertools.chain(args, kwargs.values())
                    if isinstance(x, variables.UnspecializedPythonVariable)
                )

                return wrap_fx_proxy_cls(
                    UnspecializedPythonVariable,
                    tx,
                    proxy,
                    raw_value=raw_value,
                    need_unwrap=need_unwrap,
                )
            elif all(isinstance(x, SymNodeVariable) for x in args):
                return SymNodeVariable.create(tx, proxy, None)
            else:
                # Work around for vision_maskrcnn due to precision difference
                # specialize the dividend when float divide by tensor
                if fn is operator.truediv and isinstance(
                    args[0], variables.UnspecializedPythonVariable
                ):
                    args = list(args)
                    args[0] = args[0].as_python_constant()
                return wrap_fx_proxy(tx, proxy)

        except NotImplementedError:
            unimplemented(
                gb_type="unimplemented builtin op on tensor arguments",
                context=f"partial tensor op: {self} {args} {kwargs}",
                explanation=f"Dynamo does not know how to trace builtin operator {self.fn} with tensor arguments",
                hints=[*graph_break_hints.SUPPORTABLE],
            )

    call_function_handler_cache: dict[
        tuple[object, ...],
        Callable[
            [
                "InstructionTranslatorBase",
                list[VariableTracker],
                dict[str, VariableTracker],
            ],
            VariableTracker,
        ],
    ] = {}

    def call_function(
        self,
        tx: "InstructionTranslatorBase",
        args: list[VariableTracker],
        kwargs: dict[str, VariableTracker],
    ) -> VariableTracker:
        if self.fn is object and not args and not kwargs:
            # object() -> a fresh opaque instance, wrapped as ObjectVariable to
            # match how SourcelessBuilder wraps bare `object` instances. Falling
            # through to the constant handler cannot build a VT from object().
            from .builder import SourcelessBuilder

            return SourcelessBuilder.create(tx, object())

        key: tuple[object, ...]
        if kwargs:
            kwargs = {k: v.realize() for k, v in kwargs.items()}
            key = (self.fn, *(type(x) for x in args), True)
        else:
            key = (self.fn, *(type(x) for x in args))

        handler = self.call_function_handler_cache.get(key)
        if not handler:
            self.call_function_handler_cache[key] = handler = self._make_handler(  # type: ignore[assignment]
                self.fn, [type(x) for x in args], bool(kwargs)
            )
        if handler is None:
            raise AssertionError(
                f"No handler found for {self.fn} with args {[type(x) for x in args]}"
            )
        return handler(tx, args, kwargs)  # type: ignore[return-value]

    def call_method(
        self,
        tx: "InstructionTranslatorBase",
        name: str,
        args: list[VariableTracker],
        kwargs: dict[str, VariableTracker],
    ) -> VariableTracker:
        if self.fn is object and name == "__setattr__":
            if len(args) != 3:
                raise AssertionError(
                    f"object.__setattr__ expects 3 args, got {len(args)}"
                )
            if len(kwargs) != 0:
                raise AssertionError(
                    f"object.__setattr__ expects no kwargs, got {len(kwargs)}"
                )
            obj, name_var, val = args
            obj = obj.realize()
            if (
                isinstance(obj, UserDefinedObjectVariable)
                and tx.output.side_effects.is_attribute_mutation(obj)
                and name_var.is_python_constant()
            ):
                return obj.method_setattr_standard(tx, name_var, val)

        if name == "__new__":
            # Supported __new__ methods
            if self.fn is object and len(args) == 1:
                if len(kwargs) != 0:
                    raise AssertionError(
                        f"object.__new__ expects no kwargs, got {len(kwargs)}"
                    )
                return tx.output.side_effects.track_new_user_defined_object(
                    self,
                    args[0],
                    args[1:],
                    tx=tx,
                )

            if self.fn is tuple and len(args) == 2 and not kwargs:
                if isinstance(args[0], BuiltinVariable) and args[0].fn is tuple:
                    init_args = unpack_iterable(tx, args[1])
                    return variables.TupleVariable(
                        init_args, mutation_type=ValueMutationNew()
                    )

                return tx.output.side_effects.track_new_user_defined_object(
                    self,
                    args[0],
                    args[1:],
                    tx=tx,
                )

        if name in _BUILTIN_CONSTANT_FOLDABLE_METHODS.get(self.fn, ()):
            if all(a.is_python_constant() for a in args) and all(
                v.is_python_constant() for v in kwargs.values()
            ):
                try:
                    fn = getattr(self.fn, name)
                    res = fn(
                        *(a.as_python_constant() for a in args),
                        **{k: v.as_python_constant() for k, v in kwargs.items()},
                    )
                    return VariableTracker.build(tx, res)
                except Exception as e:
                    raise_observed_exception(
                        type(e),
                        tx,
                        args=list(e.args),
                    )

        if self.fn is object and name == "__init__":
            # object.__init__ is a no-op
            return variables.ConstantVariable.create(None)

        if self.fn in (set, frozenset, list, tuple):
            if isinstance(args[0], variables.UserDefinedObjectVariable):
                if args[0]._base_vt is None:
                    raise AssertionError(
                        "UserDefinedObjectVariable._base_vt must not be None"
                    )
                return args[0]._base_vt.call_method(tx, name, args[1:], kwargs)
            else:
                return args[0].call_method(tx, name, args[1:], kwargs)

        if (
            name in ("__eq__", "__ne__", "__lt__", "__le__", "__gt__", "__ge__")
            and len(args) == 2
            and not kwargs
            and isinstance(self.fn, type)
            and args[0].is_python_constant()
            and args[1].is_python_constant()
        ):
            # Unbound rich-comparison dunder, e.g. complex.__eq__(1+1j, 2).
            # Invoke only the left type's slot on the constants, mirroring
            # CPython (returns NotImplemented rather than falling back to the
            # reflected operation when the operands are incompatible).
            lval = args[0].as_python_constant()
            if isinstance(lval, self.fn):
                return ConstantVariable.create(
                    getattr(self.fn, name)(lval, args[1].as_python_constant())
                )

        if self.fn is str and len(args) >= 1:
            resolved_fn = getattr(self.fn, name, None)
            if resolved_fn in str_methods:
                # Only delegate to ConstantVariable, not other types that happen to be constants
                if isinstance(args[0], ConstantVariable):
                    return args[0].call_method(tx, name, args[1:], kwargs)

        if self.fn is float and len(args) >= 1:
            # Only delegate to ConstantVariable, not other types that happen to be constants
            if isinstance(args[0], ConstantVariable):
                return VariableTracker.build(
                    tx, getattr(float, name)(args[0].as_python_constant())
                )

        if name == "__len__" and len(args) == 1 and not kwargs:
            # type.__len__(instance) → len(instance)
            # e.g. list.__len__(my_list) → len(my_list)
            return generic_size(tx, args[0])

        if name == "__str__" and len(args) == 1 and not kwargs:
            return super().call_method(tx, name, args, kwargs)

        if name == "__repr__" and len(args) == 1 and not kwargs:
            return super().call_method(tx, name, args, kwargs)

        if name == "__iter__" and len(args) == 1 and not kwargs:
            # type.__iter__(instance) → iter(instance)
            # e.g., tuple.__iter__(my_tuple) → iter(my_tuple)
            # For builtin types called on user-defined subclasses, use the base iterator
            return generic_getiter(tx, args[0])

        if name == "__neg__" and len(args) == 1 and not kwargs:
            # type.__neg__(instance) → neg(instance)
            # e.g., int.__neg__(4) → neg(4)
            return pynumber_negative(tx, args[0])

        if name == "__pos__" and len(args) == 1 and not kwargs:
            # type.__pos__(instance) → pos(instance)
            # e.g., int.__pos__(4) → pos(4)
            return pynumber_positive(tx, args[0])

        if name == "__abs__" and len(args) == 1 and not kwargs:
            # type.__abs__(instance) → abs(instance)
            # e.g., int.__abs__(-4) → abs(-4)
            return pynumber_absolute(tx, args[0])

        if name == "__invert__" and len(args) == 1 and not kwargs:
            # type.__invert__(instance) → ~instance
            # e.g., int.__invert__(4) → ~4
            return pynumber_invert(tx, args[0])

        if name == "__hash__" and len(args) == 1 and not kwargs:
            arg = args[0]
            if (
                isinstance(arg, variables.UserDefinedConstantVariable)
                and arg._base_vt is not None
            ):
                return generic_hash(tx, arg._base_vt)

        return super().call_method(tx, name, args, kwargs)

    def call_int(
        self,
        tx: "InstructionTranslatorBase",
        arg: VariableTracker,
        base: VariableTracker | None = None,
    ) -> VariableTracker | None:
        if base is None:
            return pynumber_int(tx, arg)
        return pylong_from_base(tx, arg, base)

    def call_float(
        self, tx: "InstructionTranslatorBase", arg: VariableTracker
    ) -> VariableTracker | None:
        return pynumber_float(tx, arg)

    def call_bin(
        self, tx: "InstructionTranslatorBase", arg: VariableTracker
    ) -> VariableTracker | None:
        return pynumber_tobase(tx, arg, 2)

    def call_oct(
        self, tx: "InstructionTranslatorBase", arg: VariableTracker
    ) -> VariableTracker | None:
        return pynumber_tobase(tx, arg, 8)

    def call_hex(
        self, tx: "InstructionTranslatorBase", arg: VariableTracker
    ) -> VariableTracker | None:
        return pynumber_tobase(tx, arg, 16)

    def call_bool(
        self, tx: "InstructionTranslatorBase", arg: VariableTracker
    ) -> VariableTracker | None:
        # Emulate PyBool_Type.tp_vectorcall which boils down to PyObject_IsTrue.
        return generic_is_true(tx, arg)

    def call_hash(
        self, tx: "InstructionTranslatorBase", arg: VariableTracker
    ) -> VariableTracker:
        return generic_hash(tx, arg)

    def call_repr(
        self, tx: "InstructionTranslatorBase", arg: VariableTracker
    ) -> VariableTracker | None:
        return generic_repr(tx, arg)

    def call_str(
        self, tx: "InstructionTranslatorBase", arg: VariableTracker
    ) -> VariableTracker | None:
        return generic_str(tx, arg)

    def call___build_class__(self, tx, *args, **kwargs):
        def fail(args, kwargs) -> NoReturn:
            unimplemented(
                gb_type="Invalid call to __build_class__",
                context=f"Non-constant args to __build_class__: {args} {kwargs}",
                explanation="Cannot trace class definition: the class body function is unsupported or the base class argument are not compile-time constants",
                hints=[*graph_break_hints.SUPPORTABLE],
            )

        if not torch._dynamo.config.enable_trace_load_build_class:
            fail(args, kwargs)

        try:
            if isinstance(args[0], variables.NestedUserFunctionVariable):
                fn = args[0].get_function(allow_sourced_cells=True)
            else:
                fn = args[0].get_function()
        except NotImplementedError:
            fail(args, kwargs)

        if check_constant_args(args[1:], kwargs):
            r = builtins.__build_class__(
                fn,  # type: ignore[possibly-undefined]
                *[a.as_python_constant() for a in args[1:]],
            )
            return VariableTracker.build(tx, r)
        else:
            fail(args, kwargs)

    def _call_min_max(
        self,
        tx: "InstructionTranslatorBase",
        *args: VariableTracker,
        key: VariableTracker | None = None,
        default: VariableTracker | None = None,
    ) -> VariableTracker | None:
        name = self.fn.__name__
        if len(args) == 0:
            raise_type_error(tx, f"{name} expected at least 1 argument, got 0")

        # `default` is keyword-only and only valid with a single iterable arg.
        positional = len(args) > 1
        if positional and default is not None:
            raise_type_error(
                tx,
                f"Cannot specify a default for {name}() with multiple positional arguments",
            )

        if key is not None and key.is_constant_none():
            key = None

        items = list(args) if positional else unpack_iterable(tx, args[0])

        if len(items) == 0:
            if default is not None:
                return default
            raise_value_error(tx, f"{name}() iterable argument is empty")

        if key is None:
            return self._call_min_max_seq(tx, items)
        return self._call_min_max_seq_with_key(tx, items, key)

    def _call_min_max_seq(
        self, tx: "InstructionTranslatorBase", items: list[VariableTracker]
    ) -> VariableTracker:
        if len(items) <= 0:
            raise AssertionError("_call_min_max_seq requires at least one item")
        if len(items) == 1:
            return items[0]

        return functools.reduce(functools.partial(self._call_min_max_binary, tx), items)  # type: ignore[arg-type,return-value]

    def _call_min_max_seq_with_key(
        self,
        tx: "InstructionTranslatorBase",
        items: list[VariableTracker],
        key: VariableTracker,
    ) -> VariableTracker:
        # Mirror CPython builtin_min_max: compare on key(item) but return the
        # original element, keeping the first extremal element on ties (only
        # replace on a strict comparison). Like list.sort, comparisons are done
        # through Dynamo and must fold to a compile-time constant, so Tensor and
        # SymInt keys graph break.
        keyvals = [key.call_function(tx, [item], {}) for item in items]
        best_item, best_key = items[0], keyvals[0]
        for item, keyval in zip(items[1:], keyvals[1:]):
            left, right = (best_key, keyval) if self.fn is max else (keyval, best_key)
            cmp = BuiltinVariable(operator.lt).call_function(tx, [left, right], {})
            if not cmp.is_python_constant():
                unimplemented(
                    gb_type="min/max with non-constant key",
                    context=str(keyval),
                    explanation=(
                        f"Cannot compute {self.fn.__name__}() whose key comparison is "
                        f"not a compile-time constant. Key type: {keyval.python_type()}. "
                        f"Most notably, Tensor or SymInt keys are unsupported, but ints work."
                    ),
                    hints=[
                        "Use something else as the key.",
                        *graph_break_hints.SUPPORTABLE,
                    ],
                )
            if cmp.as_python_constant():
                best_item, best_key = item, keyval
        return best_item

    def _call_min_max_binary(
        self,
        tx: "InstructionTranslatorBase",
        a: VariableTracker | None,
        b: VariableTracker | None,
    ) -> VariableTracker | None:
        if a is None or b is None:
            # a or b could be none if we reduce and _call_min_max_binary failed
            # to return something
            return None
        if self.tensor_args(a, b):
            if not a.is_tensor():
                a, b = b, a
            if not a.is_tensor():
                raise AssertionError(
                    "Expected at least one tensor argument for min/max"
                )

            # result of an item call is a scalar convert to a tensor
            if isinstance(a, FakeItemVariable):
                a = variables.TorchInGraphFunctionVariable(torch.tensor).call_function(
                    tx, [a], {}
                )

            # Dynamic input does not get resolved, rather, gets stored as call_function
            if isinstance(a, SymNodeVariable) or isinstance(b, SymNodeVariable):
                from .builder import wrap_fx_proxy_cls

                return wrap_fx_proxy_cls(
                    type(a),
                    tx=tx,
                    proxy=tx.output.create_proxy(
                        "call_function",
                        self.fn,
                        *proxy_args_kwargs([a, b], {}),
                    ),
                )

            # convert min/max to torch ops
            if b.is_python_constant():
                fn: VariableTracker
                if isinstance(a, variables.NumpyNdarrayVariable):
                    import numpy as np

                    fn = variables.NumpyVariable(np.clip)
                else:
                    fn = variables.TorchInGraphFunctionVariable(torch.clamp)
                kwargs = {"min": b} if (self.fn is max) else {"max": b}
                result = fn.call_function(tx, [a], kwargs)
            else:
                if isinstance(a, variables.NumpyNdarrayVariable):
                    import numpy as np

                    np_fn = {max: np.maximum, min: np.minimum}[self.fn]
                    fn = variables.NumpyVariable(np_fn)
                else:
                    torch_fn = {max: torch.maximum, min: torch.minimum}[self.fn]
                    fn = variables.TorchInGraphFunctionVariable(torch_fn)
                result = fn.call_function(tx, [a, b], {})

            # return unspec if both a, b are unspec or const
            if all(
                isinstance(
                    i,
                    (
                        variables.UnspecializedPythonVariable,
                        variables.ConstantVariable,
                    ),
                )
                for i in [a, b]
            ):
                if any(isinstance(val, FakeItemVariable) for val in [a, b]):
                    # type: ignore[arg-type]
                    return variables.FakeItemVariable.from_tensor_variable(result)

                if b.is_python_constant():
                    raw_b = b.as_python_constant()
                else:
                    raw_b = b.raw_value  # type: ignore[attr-defined]
                if self.fn is max:
                    raw_res = max(a.raw_value, raw_b)  # type: ignore[attr-defined]
                else:
                    raw_res = min(a.raw_value, raw_b)  # type: ignore[attr-defined]

                need_unwrap = any(
                    x.need_unwrap
                    for x in [a, b]
                    if isinstance(x, variables.UnspecializedPythonVariable)
                )
                return variables.UnspecializedPythonVariable.from_tensor_variable(
                    result,  # type: ignore[arg-type]
                    raw_res,
                    need_unwrap,
                )
            # otherwise return tensor
            else:
                return result
        elif isinstance(a, SymNodeVariable) or isinstance(b, SymNodeVariable):
            py_fn = torch.sym_max if self.fn is max else torch.sym_min
            proxy = tx.output.create_proxy(
                "call_function", py_fn, *proxy_args_kwargs([a, b], {})
            )
            return SymNodeVariable.create(tx, proxy, None)
        elif isinstance(a, ConstantVariable) and isinstance(b, ConstantVariable):
            value = self.fn(
                a.as_python_constant(),
                b.as_python_constant(),
            )
            return VariableTracker.build(tx, value)
        return None

    call_min = _call_min_max
    call_max = _call_min_max

    def call_abs(
        self, tx: "InstructionTranslatorBase", arg: VariableTracker
    ) -> VariableTracker:
        return pynumber_absolute(tx, arg)

    def call_pos(
        self, tx: "InstructionTranslatorBase", arg: VariableTracker
    ) -> VariableTracker:
        return pynumber_positive(tx, arg)

    def call_index(
        self, tx: "InstructionTranslatorBase", arg: VariableTracker
    ) -> VariableTracker:
        # Specialize SymNodeVariable to a constant first, matching CPython's
        # PyNumber_Index which forces a concrete int.
        return pynumber_index(tx, arg)

    def call_round(
        self,
        tx: "InstructionTranslatorBase",
        arg: VariableTracker,
        *args: VariableTracker,
        **kwargs: VariableTracker,
    ) -> VariableTracker:
        from .builder import SourcelessBuilder

        # Call arg.__round__()
        round_method = SourcelessBuilder.create(tx, getattr).call_function(
            tx, [arg, VariableTracker.build(tx, "__round__")], {}
        )
        return round_method.call_function(tx, list(args), kwargs)

    def call_range(
        self,
        tx: "InstructionTranslatorBase",
        *args: VariableTracker,
        **kwargs: VariableTracker,
    ) -> VariableTracker:
        if kwargs:
            raise_type_error(tx, "range() takes no keyword arguments")
        if len(args) == 0:
            raise_type_error(tx, "range expected at least 1 argument, got 0")
        if len(args) > 3:
            raise_type_error(tx, f"range expected at most 3 arguments, got {len(args)}")
        args = tuple(pynumber_index(tx, arg) for arg in args)
        return variables.RangeVariable(list(args))

    def _dynamic_args(self, *args: VariableTracker, **kwargs: VariableTracker) -> bool:
        return any(isinstance(x, SymNodeVariable) for x in args) or any(
            isinstance(x, SymNodeVariable) for x in kwargs.values()
        )

    def call_slice(
        self, tx: "InstructionTranslatorBase", *args: VariableTracker
    ) -> VariableTracker:
        if not 1 <= len(args) < 4:
            raise_type_error(tx, f"slice expected at least 1 argument, got {len(args)}")
        return variables.SliceVariable(list(args), tx)

    def _dyn_proxy(
        self, tx: "InstructionTranslatorBase", *args: Any, **kwargs: Any
    ) -> VariableTracker:
        from .builder import wrap_fx_proxy

        return wrap_fx_proxy(
            tx,
            tx.output.create_proxy(
                "call_function", self.fn, *proxy_args_kwargs(args, kwargs)
            ),
        )

    def call_tuple(
        self,
        tx: "InstructionTranslatorBase",
        *args: VariableTracker,
        **kwargs: VariableTracker,
    ) -> VariableTracker | None:
        # ref: https://github.com/python/cpython/blob/main/Objects/abstract.c#L2004-L2078
        if kwargs:
            raise_type_error(
                tx,
                f"{self.fn.__name__}() takes no keyword arguments",
            )
        if len(args) == 0:
            return TupleVariable([], mutation_type=ValueMutationNew())
        elif len(args) > 1:
            raise_type_error(
                tx,
                f"{self.fn.__name__} expected at most 1 argument, got {len(args)}",
            )

        obj = args[0]
        if isinstance(obj, TupleVariable) and obj.python_type() is tuple:
            return obj

        items = unpack_iterable(tx, args[0])
        return TupleVariable(items, mutation_type=ValueMutationNew())

    def call_callable(
        self, tx: "InstructionTranslatorBase", arg: VariableTracker
    ) -> VariableTracker:
        # PyCallable_Check: callable(x) is type(x)->tp_call != NULL. Dispatch on
        # the arg's Python type slot rather than enumerating callable VTs.
        # callable() is the only handler for this builtin, so always return a
        # result (or graph break via maybe_get_python_type) -- never None, which
        # would signal "try another handler" that does not exist.
        return variables.ConstantVariable.create(
            pycallable_check(maybe_get_python_type(arg))
        )

    def call_cast(
        self, _: Any, *args: VariableTracker, **kwargs: VariableTracker
    ) -> VariableTracker | None:
        if len(args) == 2:
            return args[1]

        unimplemented(
            gb_type="bad args to builtin cast()",
            context=f"got args {args} {kwargs}",
            explanation="Dynamo expects exactly 2 args to builtin cast().",
            hints=["Ensure your call to cast() has exactly 2 arguments."],
        )

    def call_dir(
        self, tx: "InstructionTranslatorBase", arg: VariableTracker
    ) -> VariableTracker | None:
        if isinstance(arg, variables.UserDefinedClassVariable):
            return VariableTracker.build(tx, dir(arg.value))
        if isinstance(arg, BuiltinVariable):
            return VariableTracker.build(tx, dir(arg.fn))
        # Enable specialized VTs for constants to work with dir()
        if arg.is_python_constant():
            return VariableTracker.build(tx, dir(arg.as_python_constant()))
        return None

    def call_set(
        self,
        tx: "InstructionTranslatorBase",
        *args: VariableTracker,
        **kwargs: VariableTracker,
    ) -> VariableTracker:
        # ref: https://github.com/python/cpython/blob/main/Objects/setobject.c#L2708-L2735
        # CPython set_init rejects keywords before unpacking positional args, so
        # set(a=1) and set().__init__(a=1) both raise regardless of arg count.
        if kwargs:
            raise_type_error(
                tx,
                "set() takes no keyword arguments",
            )
        if len(args) == 0:
            return variables.SetVariable(set(), mutation_type=ValueMutationNew())
        elif len(args) > 1:
            raise_type_error(
                tx,
                f"set expected at most 1 argument, got {len(args)}",
            )

        s = SetVariable([], mutation_type=ValueMutationNew())
        s.call_method(tx, "update", [args[0]], kwargs)
        return s

    def call_frozenset(
        self,
        tx: "InstructionTranslatorBase",
        *args: VariableTracker,
        **kwargs: VariableTracker,
    ) -> VariableTracker:
        if kwargs:
            raise_type_error(
                tx,
                "frozenset() takes no keyword arguments",
            )
        if len(args) == 0:
            return variables.FrozensetVariable(set(), mutation_type=ValueMutationNew())
        elif len(args) > 1:
            raise_type_error(
                tx,
                f"frozenset expected at most 1 argument, got {len(args)}",
            )

        if istype(args[0], variables.FrozensetVariable):
            # CPython: frozenset(existing_frozenset) returns the same object.
            return args[0]

        # Reuse existing HashableTracker keys from a set/frozenset/dict operand
        # instead of re-hashing, mirroring CPython's set_update_internal fast
        # path (do-not-rehash-dict-keys).
        if isinstance(args[0], (variables.SetVariable, variables.ConstDictVariable)):
            items = list(args[0].items.keys())
        else:
            items = unpack_iterable(tx, args[0])
        fs = FrozensetVariable(items, mutation_type=ValueMutationNew())
        return fs

    def call_zip(
        self,
        tx: "InstructionTranslatorBase",
        *args: VariableTracker,
        **kwargs: VariableTracker,
    ) -> VariableTracker:
        # ref: https://github.com/python/cpython/blob/v3.13.3/Python/bltinmodule.c#L2822-L2887
        if kwargs:
            if not (len(kwargs) == 1 and "strict" in kwargs):
                raise_args_mismatch(
                    tx,
                    "zip",
                    "1 kwargs (`strict`)",
                    f"{len(kwargs)} kwargs",
                )
        strict = kwargs.pop("strict", ConstantVariable.create(False))
        items = []
        for arg in args:
            items.append(generic_getiter(tx, arg))
        iter_args = TupleVariable(items, mutation_type=ValueMutationNew())
        return variables.ZipVariable(
            iter_args,
            strict=strict.as_python_constant(),
            mutation_type=ValueMutationNew(),
        )

    def call_len(
        self,
        tx: "InstructionTranslatorBase",
        *args: VariableTracker,
        **kwargs: VariableTracker,
    ) -> VariableTracker:
        if kwargs:
            raise_type_error(tx, "len() takes no keyword arguments")
        if len(args) != 1:
            raise_type_error(
                tx, f"len() takes exactly one argument ({len(args)} given)"
            )
        return generic_size(tx, args[0])

    def call_length_hint(
        self,
        tx: "InstructionTranslatorBase",
        *args: VariableTracker,
        **kwargs: VariableTracker,
    ) -> VariableTracker:
        # ref: PyObject_LengthHint (Objects/abstract.c): try __len__, then
        # __length_hint__, falling back to the supplied default for either a
        # missing slot or a TypeError raised by the slot.
        if kwargs or not (1 <= len(args) <= 2):
            raise_type_error(
                tx, f"length_hint expected 1 or 2 arguments, got {len(args)}"
            )
        obj = args[0]
        default = args[1] if len(args) == 2 else ConstantVariable.create(0)

        obj_type = maybe_get_python_type(obj)

        if type_implements_sq_length(obj_type) or type_implements_mp_length(obj_type):
            return generic_size(tx, obj)

        if getattr(obj_type, "__length_hint__", None) is None:
            return default
        try:
            return obj.call_method(tx, "__length_hint__", [], {})
        except ObservedTypeError:
            handle_observed_exception(tx)
            return default

    def call_getitem(
        self,
        tx: "InstructionTranslatorBase",
        *args: VariableTracker,
        **kwargs: VariableTracker,
    ) -> VariableTracker:
        if kwargs:
            raise_type_error(tx, "_operator.getitem() takes no keyword arguments")
        if len(args) != 2:
            raise_type_error(tx, f"getitem expected 2 arguments, got {len(args)}")
        return generic_getitem(tx, args[0], args[1])

    def call_setitem(
        self,
        tx: "InstructionTranslatorBase",
        *args: VariableTracker,
        **kwargs: VariableTracker,
    ) -> VariableTracker:
        if kwargs:
            raise_type_error(tx, "_operator.setitem() takes no keyword arguments")
        if len(args) != 3:
            raise_type_error(tx, f"setitem expected 3 arguments, got {len(args)}")
        return generic_setitem(tx, args[0], args[1], args[2])

    def call_delitem(
        self,
        tx: "InstructionTranslatorBase",
        *args: VariableTracker,
        **kwargs: VariableTracker,
    ) -> VariableTracker:
        if kwargs:
            raise_type_error(tx, "_operator.delitem() takes no keyword arguments")
        if len(args) != 2:
            raise_type_error(tx, f"delitem expected 2 arguments, got {len(args)}")
        return generic_delitem(tx, args[0], args[1])

    def call_isinstance(
        self,
        tx: "InstructionTranslatorBase",
        arg: VariableTracker,
        isinstance_type_var: VariableTracker,
    ) -> VariableTracker:
        try:
            arg_type = arg.python_type()
        except NotImplementedError:
            unimplemented(
                gb_type="builtin isinstance() cannot determine type of argument",
                context=f"isinstance({arg}, {isinstance_type_var})",
                explanation=f"Dynamo doesn't have a rule to determine the type of argument {arg}",
                hints=[*graph_break_hints.DYNAMO_BUG],
            )
        isinstance_type = isinstance_type_var.as_python_constant()
        # An AsyncCollectiveTensor (ACT) input's tensor-class guard is relaxed
        # (see VariableBuilder.wrap_tensor): the cache entry does not discriminate
        # ACT from the resolved plain Tensor. isinstance() observes the class and
        # is constant-folded below, so reinstall the class guard -- but only when
        # the result would actually differ between the ACT and the resolved
        # Tensor. isinstance(w, ACT) discriminates and must recompile;
        # isinstance(w, torch.Tensor) is True for both and must stay reusable.
        if isinstance(arg, variables.TensorVariable) and arg.source is not None:
            from torch._functorch._aot_autograd.utils import (
                is_async_collective_tensor_type,
            )

            if is_async_collective_tensor_type(arg_type):
                check_types = (
                    isinstance_type
                    if isinstance(isinstance_type, tuple)
                    else (isinstance_type,)
                )
                # Guard if any checked type distinguishes ACT from torch.Tensor,
                # or conservatively if a checked entry is not a plain class.
                if any(
                    not isinstance(ty, type)
                    or issubclass(arg_type, ty) != issubclass(torch.Tensor, ty)
                    for ty in check_types
                ):
                    install_guard(arg.source.make_guard(GuardBuilder.TYPE_MATCH))
        if isinstance(arg, variables.TensorVariable) and arg.dtype is not None:
            if _uses_custom_classinfo_check(isinstance_type):
                unimplemented(
                    gb_type="builtin isinstance() with custom type check on tensor",
                    context=f"isinstance({arg}, {isinstance_type})",
                    explanation="Dynamo cannot soundly trace arbitrary custom "
                    "__instancecheck__ or __subclasscheck__ hooks on tensor "
                    "values because the hook may read external mutable state.",
                    hints=[*graph_break_hints.SUPPORTABLE],
                )

            def _tensor_isinstance(
                tensor_var: VariableTracker, tensor_type: Any
            ) -> bool:
                def check_type(ty: Any) -> bool:
                    if ty not in tensortype_to_dtype:
                        example_val = arg.as_proxy().node.meta["example_value"]
                        if (
                            is_traceable_wrapper_subclass(example_val)
                            and ty is torch.nn.parameter.Parameter
                        ):
                            # N.B: we are calling isinstance directly on the example value.
                            # torch.nn.Parameter has a meta-class that overrides __isinstance__,
                            # the isinstance check here allows us to invoke that logic.
                            return isinstance(example_val, ty)
                        else:
                            return issubclass(arg.python_type(), ty)

                    dtypes = tensortype_to_dtype[ty]
                    # pyrefly: ignore [missing-attribute]
                    return arg.dtype in dtypes

                if type(tensor_type) is tuple:
                    return any(check_type(ty) for ty in tensor_type)
                else:
                    return check_type(tensor_type)

            return VariableTracker.build(tx, _tensor_isinstance(arg, isinstance_type))
        # UserDefinedObject with C extensions can have torch.Tensor attributes,
        # so break graph.
        if isinstance(arg, variables.UserDefinedObjectVariable) and isinstance(
            arg.value, types.MemberDescriptorType
        ):
            unimplemented(
                gb_type="isinstance() called on user defined object with C extensions",
                context=f"isinstance({arg}, {isinstance_type})",
                explanation="User-defined object with C extensions can have torch.Tensor "
                "attributes; intentionally graph breaking.",
                hints=[*graph_break_hints.SUPPORTABLE],
            )
        # handle __instancecheck__ defined in user class
        if (
            isinstance(arg, variables.UserDefinedObjectVariable)
            and "__instancecheck__" in isinstance_type.__class__.__dict__
        ):
            return VariableTracker.build(
                tx,
                isinstance_type.__class__.__instancecheck__(isinstance_type, arg.value),
            )

        if isinstance(arg, variables.UserDefinedExceptionClassVariable):
            # pyrefly: ignore [unbound-name]
            return VariableTracker.build(tx, isinstance(arg_type, isinstance_type))

        isinstance_type_tuple: tuple[type, ...]
        if isinstance(isinstance_type, type) or callable(
            # E.g. isinstance(obj, typing.Sequence)
            getattr(isinstance_type, "__instancecheck__", None)
        ):
            isinstance_type_tuple = (isinstance_type,)
        elif isinstance(isinstance_type, types.UnionType):
            isinstance_type_tuple = typing.get_args(isinstance_type)
        elif isinstance(isinstance_type, tuple) and all(
            isinstance(tp, type) or callable(getattr(tp, "__instancecheck__", None))
            for tp in isinstance_type
        ):
            isinstance_type_tuple = isinstance_type
        else:
            raise_observed_exception(
                TypeError,
                tx,
                args=[
                    "isinstance() arg 2 must be a type, a tuple of types, or a union"
                ],
            )

        try:
            # NB: `isinstance()` does not call `__subclasscheck__` but use `__instancecheck__`.
            # But usually `isinstance(obj, type_info)` and `issubclass(type(obj), type_info)` gives
            # the same result.
            # WARNING: This might run arbitrary user code `__subclasscheck__` and we did not trace
            # through it. This is a limitation of the current implementation.
            # Usually `__subclasscheck__` and `__instancecheck__` can be constant fold through, it
            # might not be a big issue and we trade off it for performance.
            val = issubclass(arg_type, isinstance_type_tuple)
        except TypeError:
            val = arg_type in isinstance_type_tuple
        return VariableTracker.build(tx, val)

    def call_issubclass(
        self,
        tx: "InstructionTranslatorBase",
        left_ty: VariableTracker,
        right_ty: VariableTracker,
    ) -> VariableTracker:
        """Checks if first arg is subclass of right arg"""
        return generic_issubclass(tx, left_ty, right_ty)

    def call_super(
        self, tx: "InstructionTranslatorBase", a: VariableTracker, b: VariableTracker
    ) -> VariableTracker:
        return variables.SuperVariable(a, b)

    def call_next(
        self,
        tx: "InstructionTranslatorBase",
        *args: VariableTracker,
        **kwargs: VariableTracker,
    ) -> VariableTracker:
        if kwargs:
            raise_type_error(tx, "next() takes no keyword arguments")
        if len(args) == 0:
            raise_type_error(tx, "next expected at least 1 argument, got 0")
        if len(args) > 2:
            raise_type_error(tx, f"next expected at most 2 arguments, got {len(args)}")
        arg = args[0]
        if not pyiter_check(maybe_get_python_type(arg)):
            raise_type_error(
                tx, f"'{arg.python_type_name()}' object is not an iterator"
            )
        try:
            return arg.next_variable(tx)
        except ObservedUserStopIteration:
            if len(args) == 2:
                return args[1]
            raise

    def call_map(
        self,
        tx: "InstructionTranslatorBase",
        fn: VariableTracker,
        *seqs: VariableTracker,
        **kwargs: VariableTracker,
    ) -> VariableTracker:
        if len(seqs) == 0:
            raise_observed_exception(
                TypeError,
                tx,
                args=["map() must have at least two arguments."],
            )

        strict = ConstantVariable.create(False)
        if kwargs:
            if sys.version_info >= (3, 14):
                if not (len(kwargs) == 1 and "strict" in kwargs):
                    raise_args_mismatch(
                        tx,
                        "map",
                        "1 kwargs (`strict`)",
                        f"{len(kwargs)} kwargs",
                    )
                strict = kwargs.pop("strict", ConstantVariable.create(False))
            else:
                raise_args_mismatch(
                    tx,
                    "map",
                    "0 kwargs",
                    f"{len(kwargs)} kwargs",
                )

        iterables = [generic_getiter(tx, seq) for seq in seqs]
        iter_args = TupleVariable(iterables, mutation_type=ValueMutationNew())
        return variables.MapVariable(
            fn,
            iter_args,
            strict=strict.as_python_constant(),
            mutation_type=ValueMutationNew(),
        )

    def call_filter(
        self, tx: "InstructionTranslatorBase", fn: VariableTracker, seq: VariableTracker
    ) -> VariableTracker:
        return variables.FilterVariable(
            fn,
            generic_getiter(tx, seq),
            mutation_type=ValueMutationNew(),
        )

    def tp_getattro_impl(
        self, tx: "InstructionTranslatorBase", name: str
    ) -> VariableTracker:
        # Declarative type-attribute dispatch (__name__, __bases__, __base__,
        # __flags__), mirroring the consultation at the top of
        # VariableTracker.getattro_impl. Inlined because this override keeps its
        # own object / GetAttrVariable handling below instead of delegating.
        source = self.source and AttrSource(self.source, name)
        if self.fn is object:
            # for object, we can just directly read the attribute
            try:
                value = getattr(self.fn, name)
            except AttributeError:
                raise_observed_exception(AttributeError, tx)
            if not callable(value):
                return VariableTracker.build(tx, value, source)
        attr = getattr(self.fn, name, None)
        return variables.GetAttrVariable(
            self, name, py_type=type(attr) if attr is not None else None, source=source
        )

    def call_delattr(
        self,
        tx: "InstructionTranslatorBase",
        obj: VariableTracker,
        name_var: VariableTracker,
    ) -> VariableTracker:
        return obj.call_method(tx, "__delattr__", [name_var], {})

    def call_type(
        self, tx: "InstructionTranslatorBase", obj: VariableTracker
    ) -> VariableTracker:
        try:
            py_type = obj.python_type()
        except NotImplementedError as error:
            raise UserError(
                UserErrorType.INVALID_INPUT,
                str(error),
                case_name="unknown_python_type",
            ) from None

        source = obj.source and TypeSource(obj.source)
        if (
            source is None
            and isinstance(obj, variables.UserDefinedObjectVariable)
            and obj.cls_source
        ):
            source = obj.cls_source
        if py_type is torch.Tensor:
            # In some cases torch isn't available in globals
            name = tx.output.install_global_by_id("", torch)
            source = AttrSource(GlobalSource(name), "Tensor")

        return VariableTracker.build(tx, py_type, source)

    def call_reversed(
        self, tx: "InstructionTranslatorBase", obj: VariableTracker
    ) -> VariableTracker:
        # Mirrors CPython's builtin_reversed_impl (Python/enumobject.c)
        # https://github.com/python/cpython/blob/60403a5409ff2c3f3b07dd2ca91a7a3e096839c7/Objects/enumobject.c#L353-L395
        # 1. Look up __reversed__ via _PyObject_LookupSpecial. If found, call it.
        # 2. Else require PySequence_Check (sq_item). If absent, TypeError.
        # 3. Else build a reverse sequence iterator over __len__ + __getitem__.

        obj_type = maybe_get_python_type(obj)

        # Type-level __reversed__ lookup, mirrors _PyObject_LookupSpecial.
        # getattr_static skips descriptors / metaclass. CPython treats
        # `__reversed__ = None` on the type as an explicit opt-out, raising
        # TypeError even if the sequence protocol would otherwise work.
        reversed_attr = inspect.getattr_static(
            obj_type, "__reversed__", _MISSING_SENTINEL
        )
        if reversed_attr is None:
            raise_type_error(tx, f"'{obj_type.__name__}' object is not reversible")
        if reversed_attr is not _MISSING_SENTINEL:
            return obj.call_method(tx, "__reversed__", [], {})

        if not pysequence_check(obj_type):
            raise_type_error(tx, "argument to reversed() must be a sequence")

        return variables.UserFunctionVariable(
            polyfills.builtins.reversed_sequence_iterator
        ).call_function(tx, [obj], {})

    def call_sorted(
        self,
        tx: "InstructionTranslatorBase",
        obj: VariableTracker,
        **kwargs: VariableTracker,
    ) -> VariableTracker | None:
        if not isinstance(obj, variables.TensorVariable):
            list_var = variables.ListVariable(
                unpack_iterable(tx, obj),
                mutation_type=ValueMutationNew(),
            )
            list_var.call_method(tx, "sort", [], kwargs)
            return list_var
        return None

    def call_neg(
        self, tx: "InstructionTranslatorBase", a: VariableTracker
    ) -> VariableTracker:
        return pynumber_negative(tx, a)

    def call_invert(
        self, tx: "InstructionTranslatorBase", a: VariableTracker
    ) -> VariableTracker:
        return pynumber_invert(tx, a)

    def call_format(
        self,
        tx: "InstructionTranslatorBase",
        _format_string: VariableTracker,
        *args: VariableTracker,
        **kwargs: VariableTracker,
    ) -> VariableTracker:
        format_string = _format_string.as_python_constant()
        format_string = str(format_string)
        return StringFormatVariable.create(format_string, list(args), kwargs)

    def call_id(
        self, tx: "InstructionTranslatorBase", *args: VariableTracker
    ) -> VariableTracker:
        if len(args) != 1:
            raise_observed_exception(
                TypeError,
                tx,
                args=[f"id() takes exactly one argument ({len(args)} given)"],
            )
        arg = args[0]

        real_id = arg.get_id(tx)
        if real_id is not None:
            if arg.source:
                guard_type = arg.get_id_guard_type()
                if guard_type is not None:
                    install_guard(arg.source.make_guard(guard_type))
            return VariableTracker.build(tx, real_id)

        return FakeIdVariable(id(arg))

    def call_deepcopy(
        self, tx: "InstructionTranslatorBase", x: VariableTracker
    ) -> VariableTracker:
        unimplemented(
            gb_type="copy.deepcopy()",
            context=f"copy.deepcopy({x})",
            explanation="Dynamo does not support copy.deepcopy()",
            hints=[
                "Avoid calling copy.deepcopy()",
                *graph_break_hints.SUPPORTABLE,
            ],
        )

    def _comparison_with_tensor(
        self,
        tx: "InstructionTranslatorBase",
        left: VariableTracker,
        right: VariableTracker,
    ) -> VariableTracker:
        from .builder import wrap_fx_proxy_cls
        from .tensor import supported_tensor_comparison_op_values

        op = self.fn

        if op in [operator.is_, operator.is_not]:
            is_result = (
                left.is_tensor()
                and right.is_tensor()
                and id(extract_fake_example_value(left.as_proxy().node))
                == id(extract_fake_example_value(right.as_proxy().node))
            )
            if op is operator.is_:
                return VariableTracker.build(tx, is_result)
            else:
                return VariableTracker.build(tx, not is_result)

        if op not in supported_tensor_comparison_op_values:
            unimplemented(
                gb_type="unsupported Tensor comparison op",
                context=f"{op.__name__}({left}, {right})",
                explanation=f"Dynamo does not support the comparison op {op.__name__} "
                f"with Tensor arguments {left}, {right}",
                hints=[*graph_break_hints.SUPPORTABLE],
            )
        if (
            isinstance(left, TensorVariable)
            and isinstance(right, TensorVariable)
            and (left.size and right.size) is not None
            and left.size != right.size
        ):
            try:
                torch.broadcast_shapes(left.size, right.size)
            except RuntimeError:
                # not broadcastable, can't be compared
                unimplemented(
                    gb_type="failed to broadcast when attempting Tensor comparison op",
                    context=f"{op.__name__}({left}, {right})",
                    explanation=f"Dynamo was unable to broad cast the arguments {left}, {right} "
                    f"when attempting to trace the comparison op {op.__name__}.",
                    hints=[*graph_break_hints.USER_ERROR],
                )
        tensor_cls = left if left.is_tensor() else right
        proxy = tx.output.create_proxy(
            "call_function", op, (left.as_proxy(), right.as_proxy()), {}
        )
        return wrap_fx_proxy_cls(
            type(tensor_cls),  # handle Ndarrays and Tensors
            tx,
            proxy,
        )

    def _comparison_with_symnode(
        self,
        tx: "InstructionTranslatorBase",
        left: VariableTracker,
        right: VariableTracker,
    ) -> VariableTracker:
        from .tensor import supported_tensor_comparison_op_values

        op = self.fn

        if op not in supported_tensor_comparison_op_values:
            unimplemented(
                gb_type="unsupported SymNode comparison op",
                context=f"{op.__name__}({left}, {right})",
                explanation=f"Dynamo does not support the comparison op {op.__name__} "
                f"with SymNode arguments {left}, {right}",
                hints=[*graph_break_hints.SUPPORTABLE],
            )

        # SymNodes are numeric (int/float/bool). The non-SymNode operand
        # must be a type that can participate in a traced numeric comparison.
        # Anything else (classes, DataPtrVariable, etc.) is a different type
        # entirely — the comparison result is known at compile time.
        non_symnode = right if isinstance(left, SymNodeVariable) else left
        if not isinstance(
            non_symnode, (SymNodeVariable, ConstantVariable, TensorVariable)
        ):
            # pyrefly: ignore [bad-argument-type]
            return VariableTracker.build(tx, op(object(), None))

        proxy = tx.output.create_proxy(
            "call_function", op, (left.as_proxy(), right.as_proxy()), {}
        )
        return SymNodeVariable.create(
            tx,
            proxy,
            sym_num=None,
        )

    def call_xor(
        self, tx: "InstructionTranslatorBase", a: VariableTracker, b: VariableTracker
    ) -> VariableTracker | None:
        return binary_op(tx, a, b, "nb_xor", "^")

    def call_ixor(
        self, tx: "InstructionTranslatorBase", a: VariableTracker, b: VariableTracker
    ) -> VariableTracker | None:
        return binary_iop(tx, a, b, "nb_inplace_xor", "nb_xor", "^=")

    def call_mul(
        self, tx: "InstructionTranslatorBase", a: VariableTracker, b: VariableTracker
    ) -> VariableTracker | None:
        return pynumber_multiply(tx, a, b)

    def call_imul(
        self, tx: "InstructionTranslatorBase", a: VariableTracker, b: VariableTracker
    ) -> VariableTracker | None:
        return pynumber_inplace_multiply(tx, a, b)

    def call_matmul(
        self, tx: "InstructionTranslatorBase", a: VariableTracker, b: VariableTracker
    ) -> VariableTracker | None:
        return pynumber_matrix_multiply(tx, a, b)

    def call_imatmul(
        self, tx: "InstructionTranslatorBase", a: VariableTracker, b: VariableTracker
    ) -> VariableTracker | None:
        return pynumber_inplace_matrix_multiply(tx, a, b)

    def call_sub(
        self, tx: "InstructionTranslatorBase", a: VariableTracker, b: VariableTracker
    ) -> VariableTracker | None:
        return binary_op(tx, a, b, "nb_subtract", "-")

    def call_isub(
        self, tx: "InstructionTranslatorBase", a: VariableTracker, b: VariableTracker
    ) -> VariableTracker | None:
        return binary_iop(tx, a, b, "nb_inplace_subtract", "nb_subtract", "-=")

    def call_add(
        self, tx: "InstructionTranslatorBase", a: VariableTracker, b: VariableTracker
    ) -> VariableTracker | None:
        return pynumber_add(tx, a, b)

    def call_iadd(
        self, tx: "InstructionTranslatorBase", a: VariableTracker, b: VariableTracker
    ) -> VariableTracker | None:
        return pynumber_inplace_add(tx, a, b)

    def call_and_(
        self, tx: "InstructionTranslatorBase", a: VariableTracker, b: VariableTracker
    ) -> VariableTracker | None:
        return binary_op(tx, a, b, "nb_and", "&")

    def call_iand(
        self, tx: "InstructionTranslatorBase", a: VariableTracker, b: VariableTracker
    ) -> VariableTracker | None:
        return binary_iop(tx, a, b, "nb_inplace_and", "nb_and", "&=")

    def call_or_(
        self, tx: "InstructionTranslatorBase", a: VariableTracker, b: VariableTracker
    ) -> VariableTracker | None:
        return binary_op(tx, a, b, "nb_or", "|")

    def call_ior(
        self, tx: "InstructionTranslatorBase", a: VariableTracker, b: VariableTracker
    ) -> VariableTracker | None:
        return binary_iop(tx, a, b, "nb_inplace_or", "nb_or", "|=")

    def call_lshift(
        self, tx: "InstructionTranslatorBase", a: VariableTracker, b: VariableTracker
    ) -> VariableTracker | None:
        return binary_op(tx, a, b, "nb_lshift", "<<")

    def call_ilshift(
        self, tx: "InstructionTranslatorBase", a: VariableTracker, b: VariableTracker
    ) -> VariableTracker | None:
        return binary_iop(tx, a, b, "nb_inplace_lshift", "nb_lshift", "<<=")

    def call_rshift(
        self, tx: "InstructionTranslatorBase", a: VariableTracker, b: VariableTracker
    ) -> VariableTracker | None:
        return binary_op(tx, a, b, "nb_rshift", ">>")

    def call_irshift(
        self, tx: "InstructionTranslatorBase", a: VariableTracker, b: VariableTracker
    ) -> VariableTracker | None:
        return binary_iop(tx, a, b, "nb_inplace_rshift", "nb_rshift", ">>=")

    def call_floordiv(
        self, tx: "InstructionTranslatorBase", a: VariableTracker, b: VariableTracker
    ) -> VariableTracker | None:
        return binary_op(tx, a, b, "nb_floor_divide", "//")

    def call_ifloordiv(
        self, tx: "InstructionTranslatorBase", a: VariableTracker, b: VariableTracker
    ) -> VariableTracker | None:
        return binary_iop(tx, a, b, "nb_inplace_floor_divide", "nb_floor_divide", "//=")

    def call_truediv(
        self, tx: "InstructionTranslatorBase", a: VariableTracker, b: VariableTracker
    ) -> VariableTracker | None:
        return binary_op(tx, a, b, "nb_true_divide", "/")

    def call_itruediv(
        self, tx: "InstructionTranslatorBase", a: VariableTracker, b: VariableTracker
    ) -> VariableTracker | None:
        return binary_iop(tx, a, b, "nb_inplace_true_divide", "nb_true_divide", "/=")

    def call_mod(
        self, tx: "InstructionTranslatorBase", a: VariableTracker, b: VariableTracker
    ) -> VariableTracker | None:
        return binary_op(tx, a, b, "nb_remainder", "%")

    def call_imod(
        self, tx: "InstructionTranslatorBase", a: VariableTracker, b: VariableTracker
    ) -> VariableTracker | None:
        return binary_iop(tx, a, b, "nb_inplace_remainder", "nb_remainder", "%=")

    def call_divmod(
        self, tx: "InstructionTranslatorBase", a: VariableTracker, b: VariableTracker
    ) -> VariableTracker | None:
        # PyNumber_Divmod dispatches through the nb_divmod slot with no
        # in-place form. https://github.com/python/cpython/blob/3.13/Objects/abstract.c#L1056
        return binary_op(tx, a, b, "nb_divmod", "divmod()")

    def call_pow(
        self,
        tx: "InstructionTranslatorBase",
        a: VariableTracker,
        b: VariableTracker,
        c: VariableTracker | None = None,
    ) -> VariableTracker | None:
        return ternary_op(tx, a, b, c, "nb_power", "** or pow()")

    def call_ipow(
        self,
        tx: "InstructionTranslatorBase",
        a: VariableTracker,
        b: VariableTracker,
        c: VariableTracker | None = None,
    ) -> VariableTracker | None:
        return ternary_iop(tx, a, b, c, "nb_inplace_power", "nb_power", "**=")

    def call_not_(
        self, tx: "InstructionTranslatorBase", a: VariableTracker
    ) -> VariableTracker | None:
        if isinstance(a, SymNodeVariable):
            return SymNodeVariable.create(
                tx,
                tx.output.create_proxy(
                    "call_function", operator.not_, *proxy_args_kwargs([a], {})
                ),
                sym_num=None,
            )

        # Unwrap the underlying ConstDictVariable
        if isinstance(a, DictViewVariable):
            a = a.dv_dict
        if isinstance(a, (ListVariable, ConstDictVariable, SetVariable)):
            return VariableTracker.build(tx, len(a.items) == 0)
        if isinstance(a, UserDefinedObjectVariable):
            bool_result = self.call_bool(tx, a)
            return VariableTracker.build(tx, not bool_result.value)  # type: ignore[missing-attribute]

        return None

    def call_contains(
        self, tx: "InstructionTranslatorBase", a: VariableTracker, b: VariableTracker
    ) -> VariableTracker:
        return pysequence_contains(tx, a, b)


class DictBuiltinVariable(BaseBuiltinVariable):
    """Variable tracker for the `dict` builtin constructor."""

    _fn = dict

    def __init__(self, value: type = dict, **kwargs: Any) -> None:
        if value is not dict:
            raise AssertionError(f"DictBuiltinVariable value must be dict, got {value}")
        super().__init__(**kwargs)

    def __repr__(self) -> str:
        return "DictBuiltinVariable()"

    def call_function(
        self,
        tx: "InstructionTranslatorBase",
        args: list[VariableTracker],
        kwargs: dict[str, VariableTracker],
    ) -> VariableTracker:
        return DictBuiltinVariable.call_custom_dict(tx, dict, *args, **kwargs)

    def call_method(
        self,
        tx: "InstructionTranslatorBase",
        name: str,
        args: list[VariableTracker],
        kwargs: dict[str, VariableTracker],
    ) -> VariableTracker:
        if name == "__new__":
            if args:
                # dict.__new__ (tp_new) ignores extra args — only the first
                # arg (the type) matters.  Pass init_args=[] so reconstruction
                # emits base_cls.__new__(cls) without extras.
                # https://github.com/python/cpython/blob/v3.13.0/Objects/dictobject.c#L4735-L4768
                dict_vt = ConstDictVariable({}, mutation_type=ValueMutationNew())
                if isinstance(args[0], DictBuiltinVariable):
                    return dict_vt
                return tx.output.side_effects.track_new_user_defined_object(
                    self,
                    args[0],
                    [],
                    tx=tx,
                )

        if name == "fromkeys":
            return DictBuiltinVariable.call_custom_dict_fromkeys(
                tx, dict, *args, **kwargs
            )

        resolved_fn = getattr(dict, name, None)
        if resolved_fn is not None and resolved_fn in dict_methods:
            if isinstance(args[0], variables.UserDefinedDictVariable):
                if args[0]._base_vt is None:
                    raise AssertionError(
                        "UserDefinedDictVariable._base_vt must not be None for dict method dispatch"
                    )
                return args[0]._base_vt.call_method(tx, name, args[1:], kwargs)
            elif isinstance(args[0], ConstDictVariable):
                return args[0].call_method(tx, name, args[1:], kwargs)

        return super().call_method(tx, name, args, kwargs)

    @staticmethod
    def call_custom_dict(
        tx: "InstructionTranslatorBase",
        user_cls: type,
        /,
        *args: VariableTracker,
        **kwargs: VariableTracker,
    ) -> VariableTracker:
        args_list = list(args)
        return tx.inline_user_function_return(
            VariableTracker.build(tx, polyfills.construct_dict),
            [VariableTracker.build(tx, user_cls), *args_list],
            kwargs,
        )

    @staticmethod
    def call_custom_dict_fromkeys(
        tx: "InstructionTranslatorBase",
        user_cls: type,
        /,
        *args: VariableTracker,
        **kwargs: VariableTracker,
    ) -> VariableTracker:
        if user_cls not in {dict, OrderedDict, defaultdict}:
            unimplemented(
                gb_type="Unsupported dict type for fromkeys()",
                context=f"{user_cls.__name__}.fromkeys(): {args} {kwargs}",
                explanation=f"Failed to call {user_cls.__name__}.fromkeys() because "
                f"{user_cls.__name__} is not any type of dict, OrderedDict, or defaultdict",
                hints=[
                    f"Ensure {user_cls.__name__} is a type of dict, OrderedDict, or defaultdict.",
                ],
            )
        if kwargs:
            # Only `OrderedDict.fromkeys` accepts `value` passed by keyword
            if (
                user_cls is not OrderedDict
                or len(args) != 1
                or len(kwargs) != 1
                or "value" not in kwargs
            ):
                raise_args_mismatch(
                    tx,
                    f"{user_cls.__name__}.fromkeys",
                    "1 args and 1 kwargs (`value`)",
                    f"{len(args)} args and {len(kwargs)} kwargs",
                )
            args = (*args, kwargs.pop("value"))
        if len(args) == 0:
            raise_args_mismatch(
                tx,
                f"{user_cls.__name__}.fromkeys",
                "at least 1 args",
                f"{len(args)} args",
            )
        if len(args) == 1:
            args = (*args, ConstantVariable.create(None))
        if len(args) != 2:
            raise_args_mismatch(
                tx,
                f"{user_cls.__name__}.fromkeys",
                "2 args",
                f"{len(args)} args",
            )

        arg, value = args

        def _make_result(
            items: dict[VariableTracker, VariableTracker],
        ) -> VariableTracker:
            if user_cls is OrderedDict:
                return OrderedDictVariable(items, mutation_type=ValueMutationNew())
            elif user_cls is defaultdict:
                from .builder import SourcelessBuilder
                from .user_defined import DefaultDictVariable

                result = tx.output.side_effects.track_new_user_defined_object(
                    SourcelessBuilder.create(tx, dict),
                    SourcelessBuilder.create(tx, defaultdict),
                    [],
                    tx=tx,
                )
                if not isinstance(result, DefaultDictVariable):
                    raise AssertionError(
                        f"Expected DefaultDictVariable, got {type(result)}"
                    )
                result._base_vt = ConstDictVariable(
                    items, mutation_type=ValueMutationNew()
                )
                return result
            else:
                return ConstDictVariable(items, mutation_type=ValueMutationNew())

        # Reuse the operand's existing HashableTracker keys instead of
        # re-wrapping (and thus re-hashing) the underlying VTs, mirroring
        # CPython's do-not-rehash-dict-keys behavior when building a dict from
        # an existing set/frozenset/dict.
        if isinstance(arg, (variables.SetVariable, ConstDictVariable)):
            # HashableTracker keys are accepted by ConstDictVariable.__init__.
            return _make_result(dict.fromkeys(arg.items.keys(), value))  # type: ignore[arg-type]
        if isinstance(arg, dict):
            arg_list = [VariableTracker.build(tx, k) for k in arg]
            return _make_result(dict.fromkeys(arg_list, value))
        elif iterator := generic_getiter(tx, arg):
            keys = unpack_iterable(tx, iterator)
            if all(is_hashable(v) for v in keys):
                return _make_result(dict.fromkeys(keys, value))

        unimplemented(
            gb_type="failed to call dict.fromkeys()",
            context=f"{user_cls.__name__}.fromkeys(): {args} {kwargs}",
            explanation=f"Failed to call {user_cls.__name__}.fromkeys() because "
            "arguments could not be automatically converted to a list, "
            "or some dict key is not hashable.",
            hints=[
                "Manually convert the argument to a list.",
                "Ensure all keys are hashable.",
            ],
        )


class IterBuiltinVariable(BaseBuiltinVariable):
    """Variable tracker for the `iter` builtin."""

    _fn = iter

    def __init__(self, value: Any = iter, **kwargs: Any) -> None:
        if value is not iter:
            raise AssertionError(f"IterBuiltinVariable value must be iter, got {value}")
        super().__init__(**kwargs)

    def __repr__(self) -> str:
        return "IterBuiltinVariable()"

    def call_function(
        self,
        tx: "InstructionTranslatorBase",
        args: list[VariableTracker],
        kwargs: dict[str, VariableTracker],
    ) -> VariableTracker:
        # ref: https://github.com/python/cpython/blob/v3.13.0/Python/bltinmodule.c#L1666-L1682

        if not args:
            raise_observed_exception(
                TypeError,
                tx,
                args=["iter expected at least 1 argument, got 0"],
            )

        if len(args) == 1:
            return generic_getiter(tx, args[0])
        else:
            return variables.UserFunctionVariable(
                polyfills.builtins.callable_iterator
            ).call_function(tx, args, kwargs)


class GetAttrBuiltinVariable(BaseBuiltinVariable):
    """Variable tracker for the `getattr` builtin."""

    _fn = getattr

    def __init__(self, value: Any = getattr, **kwargs: Any) -> None:
        if value is not getattr:
            raise AssertionError(
                f"GetAttrBuiltinVariable value must be getattr, got {value}"
            )
        super().__init__(**kwargs)

    def __repr__(self) -> str:
        return "GetAttrBuiltinVariable()"

    def call_function(
        self,
        tx: "InstructionTranslatorBase",
        args: list[VariableTracker],
        kwargs: dict[str, VariableTracker],
    ) -> VariableTracker:
        from .lazy import LazyVariableTracker

        if any(isinstance(a, LazyVariableTracker) for a in args):
            args = [
                a.realize() if isinstance(a, LazyVariableTracker) else a for a in args
            ]
        try:
            return self._call_getattr(tx, args, kwargs)
        except Unsupported:
            # Replicate the constant-fold fallback from BuiltinVariable._make_handler:
            # if all args are python constants, evaluate getattr() directly rather
            # than propagating a graph break from tp_getattro_impl.
            if not check_unspec_or_constant_args(args, kwargs):
                raise
            try:
                result = getattr(*[a.as_python_constant() for a in args])
            except AttributeError:
                raise_observed_exception(AttributeError, tx)
                raise
            except AsPythonConstantNotImplementedError:
                raise
            except Exception as exc:
                raise_observed_exception(type(exc), tx, args=list(exc.args))
                raise
            return VariableTracker.build(tx, result)

    def _call_getattr(
        self,
        tx: "InstructionTranslatorBase",
        args: list[VariableTracker],
        kwargs: dict[str, VariableTracker],
    ) -> VariableTracker:
        obj = args[0]
        name_var = args[1]
        default = args[2] if len(args) > 2 else _NO_DEFAULT

        if not name_var.is_python_constant():
            unimplemented(
                gb_type="getattr() with non-constant name argument",
                context=f"getattr({obj}, {name_var}, {default})",
                explanation="getattr() with non-constant name argument is not supported",
                hints=["Ensure the name argument of getattr() is a string"],
            )

        name = name_var.as_python_constant()
        return generic_getattr(tx, obj, name, default)


class HasAttrBuiltinVariable(BaseBuiltinVariable):
    """Variable tracker for the `hasattr` builtin."""

    _fn = hasattr

    def __init__(self, value: Any = hasattr, **kwargs: Any) -> None:
        if value is not hasattr:
            raise AssertionError(
                f"HasAttrBuiltinVariable value must be hasattr, got {value}"
            )
        super().__init__(**kwargs)

    def __repr__(self) -> str:
        return "HasAttrBuiltinVariable()"

    def call_function(
        self,
        tx: "InstructionTranslatorBase",
        args: Sequence[VariableTracker],
        kwargs: dict[str, VariableTracker],
    ) -> VariableTracker:
        from .lazy import LazyVariableTracker

        if any(isinstance(a, LazyVariableTracker) for a in args):
            args = [
                a.realize() if isinstance(a, LazyVariableTracker) else a for a in args
            ]
        if len(args) != 2 or kwargs:
            raise_observed_exception(TypeError, tx)
        obj, attr = args
        if not attr.is_python_constant():
            raise_observed_exception(TypeError, tx)
        result = obj.call_obj_hasattr(tx, attr.as_python_constant())
        if result is None:
            unimplemented(
                gb_type="hasattr() on unsupported type",
                context=f"hasattr({obj}, {attr})",
                explanation=f"hasattr() is not supported on type {obj.python_type_name()}",
                hints=[*graph_break_hints.SUPPORTABLE],
            )
        return result


class SetAttrBuiltinVariable(BaseBuiltinVariable):
    """Variable tracker for the `setattr` builtin."""

    _fn = setattr

    def __init__(self, value: Any = setattr, **kwargs: Any) -> None:
        if value is not setattr:
            raise AssertionError(
                f"SetAttrBuiltinVariable value must be setattr, got {value}"
            )
        super().__init__(**kwargs)

    def __repr__(self) -> str:
        return "SetAttrBuiltinVariable()"

    def call_function(
        self,
        tx: "InstructionTranslatorBase",
        args: Sequence[VariableTracker],
        kwargs: dict[str, VariableTracker],
    ) -> VariableTracker:
        from .lazy import LazyVariableTracker

        if any(isinstance(a, LazyVariableTracker) for a in args):
            args = [
                a.realize() if isinstance(a, LazyVariableTracker) else a for a in args
            ]
        if len(args) != 3 or kwargs:
            raise_observed_exception(TypeError, tx)
        obj, name_var, val = args
        result = self._call_setattr(tx, obj, name_var, val)
        if result is not None:
            return result
        unimplemented(
            gb_type="setattr() on unsupported type",
            context=f"setattr({obj}, {name_var}, {val})",
            explanation=f"setattr() is not supported on type {obj.python_type_name()}",
            hints=[*graph_break_hints.SUPPORTABLE],
        )

    def _call_setattr(
        self,
        tx: "InstructionTranslatorBase",
        obj: VariableTracker,
        name_var: VariableTracker,
        val: VariableTracker,
    ) -> VariableTracker | None:
        if isinstance(
            obj,
            (
                variables.DefaultDictVariable,
                variables.UserDefinedObjectVariable,
                variables.NestedUserFunctionVariable,
                variables.ExceptionVariable,
                variables.TracebackVariable,
                variables.DequeVariable,
            ),
        ):
            return obj.call_method(tx, "__setattr__", [name_var, val], {})
        elif (
            not tx.output.side_effects.is_attribute_mutation(obj)
            and obj.source is not None
            and (underlying := obj.get_value_for_setattr()) is not None
            and hasattr(underlying, "__dict__")
            and name_var.is_python_constant()
        ):
            tx.output.side_effects.track_object_existing(underlying, obj)
            name = name_var.as_python_constant()
            tx.output.side_effects.store_attr(obj, name, val)
            return val
        elif (
            tx.output.side_effects.is_attribute_mutation(obj)
            and name_var.is_python_constant()
        ):
            name = name_var.as_python_constant()
            if obj.is_tensor():
                from .builder import wrap_fx_proxy

                if name == "requires_grad":
                    # TODO(azahed98): Make it work properly
                    unimplemented(
                        gb_type="setattr() on Tensor.requires_grad",
                        context=f"setattr({obj}, {name}, {val})",
                        explanation="setattr() on Tensor.requires_grad not supported. "
                        "Mutating requires_grad can introduce a new leaf from non-leaf or vice versa in "
                        "the middle of the graph, which AOTAutograd does not currently know how to handle.",
                        hints=[*graph_break_hints.SUPPORTABLE],
                    )
                elif name == "data":
                    # [Note: set_data_on_scoped_tensor]
                    if obj.source is None:
                        unimplemented(
                            gb_type="Failed to mutate tensor data attribute",
                            context=f"setattr({obj}, {name}, {val})",
                            explanation="Dynamo only supports mutating `.data`"
                            " of tensor created outside `torch.compile` region",
                            hints=[
                                "Don't mutate `.data` on this tensor, or move "
                                "the mutation out of `torch.compile` region",
                            ],
                        )
                    elif obj.dtype != val.dtype:  # type: ignore[attr-defined]
                        unimplemented(
                            gb_type="Failed to mutate tensor data attribute to different dtype",
                            context=f"setattr({obj}, {name}, {val})",
                            explanation="Dynamo only supports mutating `.data`"
                            " of tensor to a new one with the same dtype",
                            hints=[
                                "Don't mutate `.data` on this tensor, or move "
                                "the mutation out of `torch.compile` region",
                            ],
                        )
                    elif obj.device != val.device:  # type: ignore[attr-defined]
                        obj_fake = get_fake_value(obj.as_proxy().node, tx)
                        val_fake = get_fake_value(val.as_proxy().node, tx)
                        if (
                            obj_fake.dtype != val_fake.dtype
                            or obj_fake.shape != val_fake.shape
                            or obj_fake.stride() != val_fake.stride()
                        ):
                            unimplemented(
                                gb_type="Failed to mutate tensor data attribute across devices with different shape/strides",
                                context=f"setattr({obj}, {name}, {val})",
                                explanation="Dynamo only supports cross-device `.data`"
                                " mutation when shape and strides match",
                                hints=[
                                    "Don't mutate `.data` on this tensor, or move "
                                    "the mutation out of `torch.compile` region",
                                ],
                            )

                    # Remove the old reference in tracked fakes - if we don't
                    # do this, .data value size/shape differences cause
                    # tracked fakes to produce incorrect guards. Sound
                    # because the TensorVariable from shallow_copy_data_
                    # below is new and gets installed in tracked fakes.
                    to_remove = [
                        tf for tf in tx.output.tracked_fakes if tf.source == obj.source
                    ]
                    for tf in to_remove:
                        tx.output.tracked_fakes.remove(tf)

                    # Snapshot the placeholder before
                    # shallow_copy_data_ mutates it. Record the node
                    # and snapshot so compile_and_call_fx_graph can
                    # restore the correct metadata before passing the
                    # graph to the backend.
                    input_node = obj.as_proxy().node
                    if input_node.op == "placeholder":
                        ev = input_node.meta.get("example_value")
                        if ev is not None and hasattr(ev, "fake_mode"):
                            from torch._subclasses.fake_impls import fast_detach

                            snapshot = fast_detach(ev.fake_mode, ev)
                            tx.output._shallow_copy_placeholder_snapshots.setdefault(
                                input_node, snapshot
                            )

                    with dynamo_disable_grad(tx), torch.no_grad():
                        out = wrap_fx_proxy(
                            tx,
                            tx.output.create_proxy(
                                "call_function",
                                torch.ops.aten.shallow_copy_data_,
                                *proxy_args_kwargs([obj, val], {}),
                            ),
                        )

                    return out
                elif name in ("_grad", "grad"):
                    # NOTE: [Tensor "grad" and "_grad" attr]
                    # _grad and grad share the same setter/getter, see
                    # THPVariable_properties, and here we make sure setting one
                    # enables reading `val` from the other, by routing all
                    # read/write to `grad`.
                    name = "grad"
                elif is_tensor_getset_descriptor(name):
                    # Attribute like `torch.Tensor.real` has special setters we
                    # don't yet support; it's not as simple adding an entry to
                    # the side effect mapping.
                    unimplemented(
                        gb_type="Failed to set tensor attribute",
                        context=f"setattr({obj}, {name}, {val})",
                        explanation="Dynamo doesn't support setting these tensor attributes",
                        hints=[
                            f"Don't mutate attribute '{name}' on tensors, or "
                            "move the mutation out of `torch.compile` region",
                        ],
                    )

            tx.output.side_effects.store_attr(obj, name, val)
            return val
        elif isinstance(obj, variables.NNModuleVariable):
            if not tx.output.is_root_tracer():
                unimplemented(
                    gb_type="nn.Module mutation in HigherOrderOp",
                    context=f"nn.Module: {obj}",
                    explanation="Inplace modifying nn.Module params/buffers inside HigherOrderOps is not allowed.",
                    hints=[
                        "Remove the mutation or move it outside of the HigherOrderOp.",
                        *graph_break_hints.FUNDAMENTAL,
                    ],
                )
            if name_var.is_python_constant() and isinstance(
                val, variables.TensorVariable
            ):
                assigning_fake_val = get_fake_value(val.as_proxy().node, tx)

                try:
                    getattr_var = obj.tp_getattro_impl(
                        tx, name_var.as_python_constant()
                    )
                except (AttributeError, ObservedAttributeError):
                    getattr_var = None

                if getattr_var is not None and getattr_var.is_tensor():
                    # get_fake_val will get the same fake tensor
                    existing_fake_attr = get_fake_value(getattr_var.as_proxy().node, tx)

                    # same tensor identity, setattr is a no-op
                    mod_setattr = inspect.getattr_static(obj.module_type, "__setattr__")
                    if (
                        existing_fake_attr is assigning_fake_val
                        and mod_setattr is torch.nn.Module.__setattr__
                    ):
                        return getattr_var

            obj.convert_to_unspecialized(tx)
        return None


class ListBuiltinVariable(BaseBuiltinVariable):
    """Variable tracker for the `list` builtin constructor."""

    _fn = list

    def __init__(self, value: type = list, **kwargs: Any) -> None:
        if value is not list:
            raise AssertionError(f"ListBuiltinVariable value must be list, got {value}")
        super().__init__(**kwargs)

    def __repr__(self) -> str:
        return "ListBuiltinVariable()"

    def call_function(
        self,
        tx: "InstructionTranslatorBase",
        args: list[VariableTracker],
        kwargs: dict[str, VariableTracker],
    ) -> VariableTracker:
        # ref: https://github.com/python/cpython/blob/3.13/Objects/listobject.c#L1265-L1287
        if kwargs:
            raise_type_error(
                tx,
                "list() takes no keyword arguments",
            )
        if len(args) == 0:
            return ListVariable([], mutation_type=ValueMutationNew())
        elif len(args) > 1:
            raise_type_error(
                tx,
                f"list expected at most 1 argument, got {len(args)}",
            )

        obj = args[0]
        if obj.source and not is_constant_source(obj.source):
            if isinstance(obj, TupleIteratorVariable):
                install_guard(obj.source.make_guard(GuardBuilder.TUPLE_ITERATOR_LEN))
            elif not isinstance(
                obj,
                (variables.IteratorVariable, variables.LocalGeneratorObjectVariable),
            ):
                if isinstance(
                    obj,
                    (
                        ConstDictVariable,
                        variables.OrderedSetVariable,
                        variables.DictKeySetVariable,
                    ),
                ):
                    tx.output.guard_on_key_order.add(obj.source)
                if isinstance(obj, variables.MappingProxyVariable):
                    install_guard(
                        obj.source.make_guard(GuardBuilder.MAPPING_KEYS_CHECK)
                    )
                elif not isinstance(obj, variables.UnspecializedNNModuleVariable):
                    install_guard(obj.source.make_guard(GuardBuilder.SEQUENCE_LENGTH))

        lst = ListVariable([], mutation_type=ValueMutationNew())
        lst.call_method(tx, "extend", [args[0]], {})
        return lst

    def call_method(
        self,
        tx: "InstructionTranslatorBase",
        name: str,
        args: list[VariableTracker],
        kwargs: dict[str, VariableTracker],
    ) -> VariableTracker:
        if name == "__new__":
            if len(args) == 1 and not kwargs:
                list_vt = ListVariable([], mutation_type=ValueMutationNew())
                if isinstance(args[0], ListBuiltinVariable):
                    return list_vt
                return tx.output.side_effects.track_new_user_defined_object(
                    self,
                    args[0],
                    args[1:],
                    tx=tx,
                )

        return super().call_method(tx, name, args, kwargs)


# pyrefly: ignore [deprecated]
@contextlib.contextmanager
def dynamo_disable_grad(tx: "InstructionTranslatorBase") -> typing.Iterator[None]:
    from . import GradModeVariable

    gmv = GradModeVariable.create(tx, False)
    try:
        gmv.enter(tx)
        yield
    finally:
        gmv.exit(tx)
