Allow wires and observable parameter when tracing

... qml.sample for Catalyst.

pennylane/measurements/measurements.py

@@ -23,6 +23,7 @@
 from typing import Optional, Sequence, Tuple, Union
 
 import pennylane as qml
+from pennylane.math.utils import is_abstract
 from pennylane.operation import DecompositionUndefinedError, EigvalsUndefinedError, Operator
 from pennylane.pytrees import register_pytree
 from pennylane.typing import TensorLike
@@ -162,6 +163,9 @@ def __init__(
             # Cast sequence of measurement values to list
             self.mv = obs if getattr(obs, "name", None) == "MeasurementValue" else list(obs)
             self.obs = None
+        elif is_abstract(obs):  # Catalyst program with qml.sample(m, wires=i)
+            self.mv = obs
+            self.obs = None
         else:
             self.obs = obs
             self.mv = None
@@ -171,7 +175,7 @@ def __init__(
         if wires is not None:
             if len(wires) == 0:
                 raise ValueError("Cannot set an empty list of wires.")
-            if obs is not None:
+            if obs is not None and not is_abstract(obs):
                 raise ValueError("Cannot set the wires if an observable is provided.")
 
         # _wires = None indicates broadcasting across all available wires.
@@ -306,7 +310,7 @@ def wires(self):
 
         This is the union of all the Wires objects of the measurement.
         """
-        if self.mv is not None:
+        if self.mv is not None and not is_abstract(self.mv):
             if isinstance(self.mv, list):
                 return qml.wires.Wires.all_wires([m.wires for m in self.mv])
             return self.mv.wires

pennylane/measurements/sample.py

@@ -20,6 +20,7 @@
 import numpy as np
 
 import pennylane as qml
+from pennylane.math.utils import is_abstract
 from pennylane.operation import Operator
 from pennylane.wires import Wires
 
@@ -173,7 +174,7 @@ def __init__(self, obs=None, wires=None, eigvals=None, id=None):
             return
 
         if wires is not None:
-            if obs is not None:
+            if obs is not None and not is_abstract(obs):
                 raise ValueError(
                     "Cannot specify the wires to sample if an observable is provided. The wires "
                     "to sample will be determined directly from the observable."