Expression panics instead of showing ColumnNotFoundError

[edavisau]

Checks

• I have checked that this issue has not already been reported.
• I have confirmed this bug exists on the latest version of Polars.

Reproducible example

import polars as pl

df = pl.DataFrame()

result = df.select(1 / (1 + pl.col("a")))
print(result)

Log output

thread '<unnamed>' panicked at crates/polars-plan/src/logical_plan/optimizer/simplify_expr.rs:296:14:
called `Option::unwrap()` on a `None` value
stack backtrace:
   0: rust_begin_unwind
             at /rustc/dd430bc8c22f57992ec1457a87437d14283fdd65/library/std/src/panicking.rs:645:5
   1: core::panicking::panic_fmt
             at /rustc/dd430bc8c22f57992ec1457a87437d14283fdd65/library/core/src/panicking.rs:72:14
   2: core::panicking::panic
             at /rustc/dd430bc8c22f57992ec1457a87437d14283fdd65/library/core/src/panicking.rs:127:5
   3: polars_plan::logical_plan::optimizer::simplify_expr::string_addition_to_linear_concat
   4: <polars_plan::logical_plan::optimizer::simplify_expr::SimplifyExprRule as polars_plan::logical_plan::optimizer::stack_opt::OptimizationRule>::optimize_expr
   5: polars_plan::logical_plan::optimizer::stack_opt::StackOptimizer::optimize_loop
   6: polars_plan::logical_plan::optimizer::optimize
   7: polars_lazy::frame::LazyFrame::optimize_with_scratch
   8: polars_lazy::frame::LazyFrame::prepare_collect
   9: polars_lazy::frame::LazyFrame::collect
  10: polars::lazyframe::_::<impl polars::lazyframe::PyLazyFrame>::__pymethod_collect__
  11: pyo3::impl_::trampoline::trampoline
  12: <unknown>
  13: _PyEval_EvalFrameDefault
  14: _PyFunction_Vectorcall
  15: PyObject_Call
  16: _PyEval_EvalFrameDefault
  17: <unknown>
  18: _PyEval_EvalFrameDefault
  19: _PyFunction_Vectorcall
  20: _PyEval_EvalFrameDefault
  21: <unknown>
  22: PyEval_EvalCode
  23: <unknown>
  24: <unknown>
  25: <unknown>
  26: _PyRun_InteractiveLoopObject
  27: _PyRun_AnyFileObject
  28: PyRun_AnyFileExFlags
  29: <unknown>
  30: Py_BytesMain
  31: <unknown>
  32: __libc_start_main
  33: _start

Issue description

The ordering/choice of the operators matter to cause this panic
e.g. 1 / (pl.col("a") + 1) and 1 / (1 - pl.col("a")) are both fine

Expected behavior

Code above should give me the correct message

ColumnNotFoundError: a

Installed versions

--------Version info---------
Polars:               0.20.15
Index type:           UInt32
Platform:             Linux-5.15.0-91-generic-x86_64-with-glibc2.35
Python:               3.10.12 (main, Nov 20 2023, 15:14:05) [GCC 11.4.0]

----Optional dependencies----
adbc_driver_manager:  <not installed>
cloudpickle:          2.2.1
connectorx:           <not installed>
deltalake:            <not installed>
fastexcel:            <not installed>
fsspec:               2023.1.0
gevent:               <not installed>
hvplot:               <not installed>
matplotlib:           3.7.0
numpy:                1.26.2
openpyxl:             3.1.2
pandas:               1.5.3
pyarrow:              14.0.1
pydantic:             1.10.5
pyiceberg:            <not installed>
pyxlsb:               <not installed>
sqlalchemy:           1.4.46
xlsx2csv:             <not installed>
xlsxwriter:           <not installed>