Fix native cu3 rewrite if clause (#165)

* Fix fishy if clause in rewrite_cu3

* Add simple stupid test

Author: david-pl

src/bloqade/qasm2/rewrite/native_gates.py

@@ -279,7 +279,7 @@ def rewrite_cu3(self, node: uop.CU3) -> result.RewriteResult:
         lam = self._get_const_value(node.lam)
         phi = self._get_const_value(node.phi)
 
-        if not all((theta, phi, lam)):
+        if theta is None or lam is None or phi is None:
             return result.RewriteResult()
 
         # cirq.ControlledGate(u3(theta, lambda phi))

test/qasm2/test_native.py

@@ -2,7 +2,6 @@
 import textwrap
 
 import cirq
-import cirq.contrib
 import cirq.testing
 import cirq.contrib.qasm_import as qasm_import
 import cirq.circuits.qasm_output as qasm_output
@@ -86,6 +85,18 @@ def generator(n_tests: int):
     """
     )
 
+    yield textwrap.dedent(
+        """
+    OPENQASM 2.0;
+    include "qelib1.inc";
+
+    qreg q[2];
+
+    cu3(0.0, 0.6, 3.141591) q[0],q[1];
+
+    """
+    )
+
     rgen = np.random.RandomState(128)
     for num in range(n_tests):
         # Generate a new instance:
@@ -117,3 +128,28 @@ def kernel():
     cirq.testing.assert_allclose_up_to_global_phase(
         cirq.unitary(old_circuit), cirq.unitary(cirq_circuit), atol=1e-8
     )
+
+
+def test_cu3_rewrite():
+    prog = textwrap.dedent(
+        """
+        OPENQASM 2.0;
+        include "qelib1.inc";
+
+        qreg q[2];
+
+        cu3(0.0, 0.6, 3.141591) q[0],q[1];
+
+        """
+    )
+
+    @qasm2.main.add(qasm2.dialects.inline)
+    def kernel():
+        qasm2.inline(prog)
+
+    walk.Walk(RydbergGateSetRewriteRule(kernel.dialects)).rewrite(kernel.code)
+
+    new_qasm2 = qasm2.emit.QASM2().emit_str(kernel)
+
+    # simple-stupid test to see if the rewrite injected a bunch of new lines
+    assert new_qasm2.count("\n") > prog.count("\n")