Bug summary
I have a pcolormesh that has shading='gouraud', and I am trying to save it to an .eps. If I save the image as .png everything works fine, but when I save it as .eps it gives error. A similar issue was already open and then closed in the past.

Code for reproduction
import matplotlib.pyplot as plt
import numpy as np
plt.pcolormesh(np.random.randn(10,10), shading='gouraud')
plt.gcf().savefig('test.eps')

Matplotlib version
matplotlib 3.1.1
Python 3.6.8 |Anaconda custom (64-bit)| (default, Feb 21 2019, 18:30:04) [MSC v.1916 64 bit (AMD64)]