Bug report

Bug summary

When using named arguments for x and y, the plots created with plt.plot respectively ax.plot are keeping empty. plt.errorbar (or ax.errorbar) are producing the desired output (see code below).
The documentation shows that x and y are valid named arguments.

Code for reproduction

import matplotlib.pyplot as plt
import numpy as np

x = np.arange(0, 12, .5)
y = np.random.rand(*x.shape)
plt.plot(x, y) #  works as expected
plt.plot(x=x, y=y) # shows empty plot
plt.errorbar(x=x, y=y) # works as expected

Actual outcome

Expected outcome

or

Matplotlib version

• Operating system: Windows 10x64
• Matplotlib version: 2.2.3 (had the same issue with 2.2.2)
• Matplotlib backend (print(matplotlib.get_backend())): 'module://ipykernel.pylab.backend_inline'
• Python version: 3.6.2
• Jupyter version (if applicable): 1.0.0 (Jupyter notebook 5.1.0rrc1)
• Other libraries: numpy 1.14.5+mkl

Python was installed using WinPython, packages installed with pip.