Next: Improve error on wrong field operator return type annotation

[tehrengruber]

If the annotated return type of a field operator does not match the deduced one, the error message should point the user to the annotation. Currently the error looks like this:

Traceback (most recent call last):
  File "<frozen importlib._bootstrap>", line 1027, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1006, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 688, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 883, in exec_module
  File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
  File ".../FVM_advection_sphere/src/fvm_advection_sphere/advection.py", line 337, in <module>
    def upwind_scheme(
  File ".../gt4py_functional/src/gt4py/next/ffront/decorator.py", line 637, in field_operator_inner
    return FieldOperator.from_function(definition, backend)
  File ".../gt4py_functional/src/gt4py/next/ffront/decorator.py", line 467, in from_function
    foast_definition_node = FieldOperatorParser.apply(source_def, closure_vars, annotations)
  File ".../gt4py_functional/src/gt4py/next/ffront/dialect_parser.py", line 119, in apply
    output_ast = cls._postprocess_dialect_ast(
  File ".../gt4py_functional/src/gt4py/next/ffront/func_to_foast.py", line 112, in _postprocess_dialect_ast
    raise common.GTTypeError(
gt4py.next.common.GTTypeError: Annotated return type does not match deduced return type. Expected `Field[[Vertex, K], float64]`, but got `Field[[Vertex], float64]`.
python-BaseException