pl.when('a').then(-pl.col.b) creates a column called "literal", even though its meta.output_name() is "b"

[Wainberg]

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

>>> pl.DataFrame({'a': [True, False], 'b': [1, 2]}).select(pl.when('a').then(pl.col.b))
 b
 1
 null
shape: (2, 1)
>>> pl.DataFrame({'a': [True, False], 'b': [1, 2]}).select(pl.when('a').then(-pl.col.b))
 literal
 -1
 null
shape: (2, 1)
>>> pl.when('a').then(-pl.col.b).meta.output_name()
'b'

Log output

No response

Issue description

pl.when('a').then(-pl.col.b) creates a column called "literal", even though its meta.output_name() is "b".

Expected behavior

The column name should be "b", no?

Installed versions

--------Version info---------
Polars:              0.19.3
Index type:          UInt32
Platform:            Linux-3.10.0-1160.88.1.el7.x86_64-x86_64-with-glibc2.17
Python:              3.11.5 | packaged by conda-forge | (main, Aug 27 2023, 03:34:09) [GCC 12.3.0]

----Optional dependencies----
adbc_driver_sqlite:  <not installed>
cloudpickle:         <not installed>
connectorx:          <not installed>
deltalake:           <not installed>
fsspec:              <not installed>
gevent:              <not installed>
matplotlib:          3.8.0
numpy:               1.26.0
pandas:              2.1.1
pyarrow:             13.0.0
pydantic:            <not installed>
sqlalchemy:          <not installed>
xlsx2csv:            0.8.1
xlsxwriter:          3.1.4

[reswqa]

This maybe already fixed in main branch.

[alexander-beedie]

Can confirm that this was fixed by #11158; will be in the upcoming 0.19.4 👍