[panic] internal error: entered unreachable code: Two equal, normalized intersections should share the same Salsa ID #2451
Description
Summary
Given following Python code:
from typing import Any, TypedDict, cast
class A(TypedDict):
x: str
class B(TypedDict):
y: str
T = int | A | B
def test(a: Any, items: list[T]) -> None:
combined = a or items
v = combined[0]
if isinstance(v, dict):
cast(T, v)ty check panicked:
❯ ty check /tmp/t.py
error[panic]: Panicked at crates/ty_python_semantic/src/types/type_ordering.rs:270:13 when checking `/tmp/t.py`: `internal error: entered unreachable code: Two equal, normalized intersections should share the same Salsa ID`
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: linux x86_64
info: Version: 0.0.11+1 (22e97ecdd 2026-01-09)
info: Args: ["ty", "check", "/tmp/t.py"]
info: Backtrace:
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info: query stacktrace:
0: infer_expression_types_impl(Id(1805))
at crates/ty_python_semantic/src/types/infer.rs:196
1: infer_scope_types(Id(1003))
at crates/ty_python_semantic/src/types/infer.rs:69
2: check_file_impl(Id(c00))
at crates/ty_project/src/lib.rs:554
Version
ty 0.0.11+1 (22e97ec 2026-01-09)