ValueError: _internal_op_tensor_inplace_fill does not support dynamic index

- I am here reporting a bug when working with coreml model referring to, "facebook/mms-tts-eng," which is a text-to-speech (TTS) model available through Facebook's repository, likely designed for use with Hugging Face's Transformers library.
- Converting this specific model to Core ML format using coremltools throwing an error stating that internal tensor doesnot support the dynamic index . Here is the conversion code script in the url here. [https://colab.research.google.com/drive/1Lyl64_dwryrF7z9FZqpD28XPRQTWP4A8?usp=sharing]
- Error trace
- ---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
[](https://localhost:8080/#) in ()
4 input_shape = tuple(input_ids.shape)
5 # Convert the traced model to a CoreML model
----> 6 coreml_model = coremltools.convert(
7 traced_model,
8 convert_to = "mlprogram",

9 frames
[/usr/local/lib/python3.10/dist-packages/coremltools/converters/_converters_entry.py](https://localhost:8080/#) in convert(model, source, inputs, outputs, classifier_config, minimum_deployment_target, convert_to, compute_precision, skip_model_load, compute_units, package_dir, debug, pass_pipeline)
572 )
573
--> 574 mlmodel = mil_convert(
575 model,
576 convert_from=exact_source,

[/usr/local/lib/python3.10/dist-packages/coremltools/converters/mil/converter.py](https://localhost:8080/#) in mil_convert(model, convert_from, convert_to, compute_units, **kwargs)
186 See `coremltools.converters.convert`
187 """
--> 188 return _mil_convert(model, convert_from, convert_to, ConverterRegistry, MLModel, compute_units, **kwargs)
189
190

[/usr/local/lib/python3.10/dist-packages/coremltools/converters/mil/converter.py](https://localhost:8080/#) in _mil_convert(model, convert_from, convert_to, registry, modelClass, compute_units, **kwargs)
210 kwargs["weights_dir"] = weights_dir.name
211
--> 212 proto, mil_program = mil_convert_to_proto(
213 model,
214 convert_from,

[/usr/local/lib/python3.10/dist-packages/coremltools/converters/mil/converter.py](https://localhost:8080/#) in mil_convert_to_proto(model, convert_from, convert_to, converter_registry, main_pipeline, **kwargs)
284
285 frontend_converter = frontend_converter_type()
--> 286 prog = frontend_converter(model, **kwargs)
287 PassPipelineManager.apply_pipeline(prog, frontend_pipeline)
288

[/usr/local/lib/python3.10/dist-packages/coremltools/converters/mil/converter.py](https://localhost:8080/#) in __call__(self, *args, **kwargs)
106 from .frontend.torch.load import load
107
--> 108 return load(*args, **kwargs)
109
110

[/usr/local/lib/python3.10/dist-packages/coremltools/converters/mil/frontend/torch/load.py](https://localhost:8080/#) in load(spec, inputs, specification_version, debug, outputs, cut_at_symbols, use_default_fp16_io, **kwargs)
78 )
79
---> 80 return _perform_torch_convert(converter, debug)
81
82

[/usr/local/lib/python3.10/dist-packages/coremltools/converters/mil/frontend/torch/load.py](https://localhost:8080/#) in _perform_torch_convert(converter, debug)
97 def _perform_torch_convert(converter: TorchConverter, debug: bool) -> Program:
98 try:
---> 99 prog = converter.convert()
100 except RuntimeError as e:
101 if debug and "convert function" in str(e):

[/usr/local/lib/python3.10/dist-packages/coremltools/converters/mil/frontend/torch/converter.py](https://localhost:8080/#) in convert(self)
517
518 # Add the rest of the operations
--> 519 convert_nodes(self.context, self.graph)
520
521 graph_outputs = [self.context[name] for name in self.graph.outputs]

[/usr/local/lib/python3.10/dist-packages/coremltools/converters/mil/frontend/torch/ops.py](https://localhost:8080/#) in convert_nodes(context, graph)
86 context.prepare_for_conversion(node)
87
---> 88 add_op(context, node)
89
90 if _TORCH_OPS_REGISTRY.is_inplace_op(op_lookup):

[/usr/local/lib/python3.10/dist-packages/coremltools/converters/mil/frontend/torch/ops.py](https://localhost:8080/#) in _internal_op_tensor_inplace_fill(context, node)
3574 )
3575 if begin.val is None or end.val is None or any_symbolic(data.shape):
-> 3576 raise ValueError("_internal_op_tensor_inplace_fill does not support dynamic index")
3577
3578 fill_shape = solve_slice_by_index_shape(

ValueError: _internal_op_tensor_inplace_fill does not support dynamic index

Start with the linked conversion notebook and the failing entry point in coremltools/converters/mil/frontend/torch/ops.py, especially _internal_op_tensor_inplace_fill. Reproduce the facebook/mms-tts-eng conversion and inspect how the dynamic index reaches that operation. Done means the model conversion no longer raises this ValueError and the behavior is validated against the reported example.

Written by the indexing model from the issue text.