panic: internal error: entered unreachable code: IPython escape command expression is only allowed for % and ! #21465
Description
Summary
This panic was originally reported without a reproducer at facebook/pyrefly#1559 . I was able to track it down with some targeted fuzzing:
panic: Panicked at crates/ruff_python_parser/src/parser/expression.rs:2782:13 when checking `/home/user/crash.ipynb`: `internal error: entered unreachable code: IPython escape command expression is only allowed for % and !`
--> crash.ipynb:1:1
crash.ipynb
{
"cells": [
{
"cell_type": "code",
"metadata": {},
"outputs": [],
"source": [
"with a,?b\n?"
]
}
],
"metadata": {},
"nbformat": 4,
"nbformat_minor": 2
}
Version
ruff 0.14.5