Panic if a self-referential base is passed to a three-argument type() call #2564
Description
ty currently panics on this:
X = type("X", (tuple["X | None"],), {})error[panic]: Panicked at /Users/alexw/.cargo/git/checkouts/salsa-e6f3bb7c2a062968/9860ff6/src/function/execute.rs:743:9 when checking `/Users/alexw/dev/ruff/foo.py`: `infer_definition_types(Id(1400)): execute: too many cycle iterations`
info: This indicates a bug in ty.
info: If you could open an issue at https://github.com/astral-sh/ty/issues/new?title=%5Bpanic%5D, we'd be very appreciative!
info: Platform: macos aarch64
info: Version: ruff/0.14.13+65 (bffc95873 2026-01-19)
info: Args: ["target/debug/ty", "check", "foo.py", "--python-version=3.14", "--ignore=undefined-reveal"]
info: run with `RUST_BACKTRACE=1` environment variable to show the full backtrace information
info: query stacktrace:
0: infer_scope_types(Id(1000))
at crates/ty_python_semantic/src/types/infer.rs:70
1: check_file_impl(Id(c00))
at crates/ty_project/src/lib.rs:554
After astral-sh/ruff#22718 has landed, things like this will also panic:
from typing import NamedTuple
X = type("X", (NamedTuple("NT", [("field", "X | int")]),), {})The fix is probably to defer inference of the bases argument in "non-dangling" three-argument type() calls, the same way as we defer inference of the bases list in regular class statements. "Non-dangling" means three-argument type() calls where the call is immediately assigned to a value, such as the above assignment to X.