get_cost_value fails when applied to a CirqGateAsBloq with a known decomposition into gates that should be countable.

[wjhuggins]

When I execute the code:

import sympy
import cirq

from qualtran.cirq_interop import CirqGateAsBloq
from qualtran.resource_counting import QECGatesCost, get_cost_value

theta = sympy.Symbol("theta", real=True)
cirq_swappow = cirq.SwapPowGate(exponent=theta)

# Would be cool if it worked:
swappow_bloq = CirqGateAsBloq(cirq_swappow)

get_cost_value(swappow_bloq, QECGatesCost())

I would expect that get_cost_value would automatically use cirq.decompose to break the SwapPowGate into gates that can be ingested by Qualtran and costed out, but instead I get an error message:

ValueError: Cirq gate must be directly countable, not SWAP**theta.

When I run (with the appropriate imports of course)

g, sigma = swappow_bloq.call_graph()

show_call_graph(g)

show_counts_sigma(sigma)

I get the expected behaviour:

[mpharrigan]

I was trying to limit the use of cirq functionality in the resource counting code but was overzealous here. I agree the call graph and resource counting code should be in agreement