[BUG] Tensor reshape only compiles when inlined

[hylkedonker]

Bug description

It looks like it is only possible to reshape a tensor immediately following it's definition.

Steps to reproduce

The following works as expected, when inlining all statements one after another:

from tensor import Tensor, TensorShape

def main():
    var a = Tensor[DType.float64](2, 1.0)
    var a_expanded_shape = TensorShape(1, 2)
    var a_reshaped = a.reshape(a_expanded_shape)

If the reshape is, however, placed inside a different function than the code no longer compiles:

from tensor import Tensor, TensorShape

fn my_reshape(a: Tensor[DType.float64]):
    var a_expanded_shape = TensorShape(1, 2)
    var a_reshaped = a.reshape(a_expanded_shape)

def main():
    var a = Tensor[DType.float64](2, 1.0)
    my_reshape(a)

Which gives the compilation error:

error: invalid call to 'reshape': invalid use of mutating method on rvalue of type 'Tensor[float64]'
var a_reshaped = a.reshape(a_expanded_shape)

Am I missing something obvious?

Reading the Tensor.reshape docs, I am expecting a.reshape to return a copy. So no mutations on the function's argument a, right?

Thanks in advance,

Hylke

System information

- Ubuntu 24.04
- `mojo --version`: mojo 2024.8.2805 (fd3bceba)
- `modular -v`: modular 0.9.2 (b3079bd5)