Loop variable read after a zero trip for returns uninitialized memory

[sacpis]

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Describe the bug

In Python, a for loop that never runs leaves its loop variable unbound, so reading it afterwards raises NameError. In a CUDA-Q kernel the read silently returns whatever is in the variable's stack slot.

Steps to reproduce the bug

import cudaq

@cudaq.kernel
def k(n: int):
    q = cudaq.qvector(3)
    for i in range(n):
        h(q[i])
    x(q[i])

print(cudaq.sample(k, 0, shots_count=20))

Gives output as

RuntimeError: Provided index [18446744073709551615] >= array size [3]

Expected behavior

Reading a loop variable after a zero trip loop should raise, matching Python's NameError, rather than produce a value.

Is this a regression? If it is, put the last known working version (or commit) here.

Not a regression

Environment

• CUDA-Q version:
• Python version:
• C++ compiler:
• Operating system:

Suggestions

No response

[sacpis]

Fixing it.