When is this needed?

WinML may report an error

self.binding.Bind("input", tensor of shape [10]);
self.binding.Bind("input", tensor of shape [11]);  <-- error

But it works

self.binding.Bind("input", tensor of shape [10]);
self.binding.Clear();
self.binding.Bind("input", tensor of shape [11]);

Ok, so this needs to be fixed then in this PR?

No, not in this one. It cannot be easily fixed by adding a self.binding.Clear() here because a model may have multiple input features. In this case, application calls set_input more than once.

I think I understand what you're saying about Clear: it erases all the bindings, even for other model inputs. We can't have that. But what happens in this conceivable sequence?

• Wasm guest calls set_input on input N with shape A
• Wasm guest again calls set_input on input N with shape B

This is valid, though silly. The user should not have to face an error from wasi-nn in this case, right? But, if WinML is going to raise an error, then should we protect this some other way, e.g., by checking that the tensor shape is what the model expects (either A or B)?

That's a variable input, accepts both A and B (like a string with different length). I feel like this is a bug of WinML, or the calling flow is incorrect. Clear fixes the issue but I'm not sure if that's the only solution, so I'm not adding Clear at this time.

We can do this once at the top of the function.

output_tensor's type is unknown at the top of the function.

How about

let itensor = inspectable.cast<ITensor>()?;
let dimensions = dimensions_as_u32(&itensor.Shape()?)?;

or something like that?

It works, but GetAsVectorView is a method of TensorFloat16Bit. Then we'll need to cast itensor again to specific tensor type. The change above makes code clean but will it be a performance issue to cast twice?

Ok, so this needs to be fixed then in this PR?