Description
Pandas version checks
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I have checked that this issue has not already been reported.
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I have confirmed this bug exists on the latest version of pandas.
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I have confirmed this bug exists on the main branch of pandas.
Reproducible Example
>>> import pandas as pd
>>> pd.Series().dtype
dtype('O') # ok
>>> pd.Series(index=[]).dtype
dtype('float64') # not ok
Issue Description
Corner case of #49342, where the dtype of an empty Series become float64, where it should be object.
Expected Behavior
Empty Series should always be of type object.
Installed Versions
INSTALLED VERSIONS
commit : bb7dd2c
python : 3.9.7.final.0
python-bits : 64
OS : Darwin
OS-release : 21.6.0
Version : Darwin Kernel Version 21.6.0: Wed Aug 10 14:28:35 PDT 2022; root:xnu-8020.141.5~2/RELEASE_ARM64_T8101
machine : arm64
processor : arm
byteorder : little
LC_ALL : None
LANG : None
LOCALE : None.UTF-8
pandas : 2.0.0.dev0+606.gbb7dd2c85d.dirty
numpy : 1.23.3
pytz : 2022.1
dateutil : 2.8.2
setuptools : 65.5.0
pip : 22.2.2
Cython : 0.29.32
pytest : 7.1.2
hypothesis : 6.37.0
sphinx : 5.0.2
blosc : 1.10.6
feather : None
xlsxwriter : None
lxml.etree : 4.9.1
html5lib : None
pymysql : 1.0.2
psycopg2 : 2.9.3
jinja2 : 3.1.2
IPython : 7.29.0
pandas_datareader: None
bs4 : 4.11.1
bottleneck : None
brotli :
fastparquet : 0.8.3
fsspec : 2022.10.0
gcsfs : None
matplotlib : 3.5.2
numba : 0.56.4
numexpr : 2.8.3
odfpy : None
openpyxl : None
pandas_gbq : None
pyarrow : 10.0.0
pyreadstat : None
pyxlsb : None
s3fs : 2022.10.0
scipy : 1.9.1
snappy : None
sqlalchemy : None
tables : 3.7.0
tabulate : 0.9.0
xarray : None
xlrd : None
zstandard : 0.18.0
tzdata : None
qtpy : None
pyqt5 : None