SIGABRT Error with GlobalisePhasedX Pass on Classically Controlled Circuits

[p51lee]

Overview

An issue analogous to the one reported in #1305 occurs when applying the GlobalisePhasedX pass to circuits containing classically conditioned gates.

Example and reproduction steps

Consider the following Python code:

import pytket
from pytket.passes import GlobalisePhasedX

circuit_tket = pytket.Circuit(2, 1)
circuit_tket.CX(0, 1, condition=pytket.Bit(0))
circuit_tket.Y(0)
circuit_tket.SX(1)
print(GlobalisePhasedX().apply(circuit_tket))
print(circuit_tket.get_commands())

Observed

Executing the above code results in a critical assertion failure and the process terminates unexpectedly with a SIGABRT signal:

True
[tket] [critical] Assertion '!"slice is empty"' (../../src/Circuit/macro_circ_info.cpp : operator++ : 935) failed.  Aborting.

Process finished with exit code 134 (interrupted by signal 6:SIGABRT)