.py

def dynfuncswitch(val, preferleft=True):
	"""Causes gcc crash."""
	return (math.floor if preferleft else math.ceil)(val)

.pxd

from libc cimport math

The above code is valid Python, and it Cythonizes fine, but it causes a crash in gcc. Typing the arguments and return of the function does not change the behaviour.

error: assignment of function ‘double __pyx_t_1(double)’
19498 |     __pyx_t_1 = floor