Reassigning a tuple with the same element types fails #2166

Bug Description

Rebinding a local tuple variable to a new tuple with the same element types fails during code generation. This is ordinary reassignment, not mutation of an immutable tuple.

Save the following as a Python file:

import warp as wp


@wp.kernel(enable_backward=False)
def evaluate(out: wp.array[float]):
    values = (2.0, 3.0)
    values = (4.0, 5.0)
    out[0] = values[0] * values[1]


out = wp.zeros(1, device="cpu")
wp.launch(evaluate, dim=1, inputs=[out], device="cpu")
print(out.numpy())

Expected: [20.0].

Actual: WarpCodegenTypeError: Error, assigning to existing symbol values (<...tuple_t object...>) with different type (<...tuple_t object...>).

Both tuples have type tuple[float, float]. The internal tuple descriptors are compared by identity rather than by their element types when checking reassignment. Equal tuple shapes and element types should be accepted; incompatible types or lengths should remain errors.

Related: #2099, #2100, #2101. This reproducer uses flat tuples, no unpacking, and disables backward generation, so it is independent of those failures. Ordinary tuple composition is also useful for structured inputs to #1813.

System Information

• Warp 1.20.0.dev0, main commit 0c1ed78f7.
• Python 3.12.3, Linux x86_64, CPU device.
• Reproduced before any of the tuple fixes were applied; failure occurs during code generation.