Original issue. Resolved in the reported scope. The raw dict.__dict__["fromkeys"] descriptor has type classmethod_descriptor; the bound dict.fromkeys has type builtin_function_or_method. Binding and representative additional native descriptors agree with CPython.

Independently rechecked on October 6, 2026 (KST): fresh inputs, results and scope.

• Source and standard library: f39b054b9c8c.
• Verified October 5, 2026 on macOS 26.5.2 ARM64.
• RustPython: 0.6.1, Python 3.14.0.alpha; native ARM64.
• Comparison: CPython 3.14.6 ARM64.

Use absolute paths for the variables below:

• RP: the RustPython executable for this commit.
• CP: the CPython 3.14.6 executable.
• SRC: the source directory at this commit, including its matching Lib.
• CASE: the directory containing the files shown below.

Shell variables replace recorded absolute paths. Export them so the Python inputs can use them:

export RP CP SRC CASE
unset PYTHONPATH PYTHONHOME PYTHONWARNINGS PYTHONSTARTUP
export PYTHONDONTWRITEBYTECODE=1

Save as 4690-original.py.

print(type(dict.__dict__["fromkeys"]))
print(type(dict.fromkeys))

cd "$SRC"

RustPython:

RUSTPYTHONPATH="$SRC/Lib" "$RP" -B "$CASE/4690-original.py"

CPython:

"$CP" -B "$CASE/4690-original.py"

Expected: The raw dict.fromkeys descriptor must be classmethod_descriptor, while the bound method remains builtin_function_or_method.

Exit code: 0. No timeout.

stdout:

<class 'classmethod_descriptor'>
<class 'builtin_function_or_method'>

stderr:

No output.

Previously recorded at 8ff947e83a65; exit code 0. This run was not repeated alongside the current results. Historical inputs may differ from the expanded checks above.

stdout:

classmethod
method

PR #8780: native OrderedDict and class-method descriptors.

First fixing commit: not established.

Recorded executable SHA-256 values:

• RustPython: a40f4d564f9c53ffcc4ec27c1a61ae3261b68cf3286f511a2ad39fb7f60c9b99.

• CPython: 58eea46bd68c84e30980ca1133d1b0efb139c878a4934a519dba0846b74069ef.

• CPython command, environment and output record.

• RustPython command, environment and output record.

• Executed source.

• Scope and complete execution inventory.

• Historical record.

AI assistance: OpenAI Codex.