# Buggy code
def fold_arguments(pysig, args, kws, normal_handler, default_handler, stararg_handler):
    """
    Given the signature *pysig*, explicit *args* and *kws*, resolve
    omitted arguments and keyword arguments. A tuple of positional
    arguments is returned.
    Various handlers allow to process arguments:
    - normal_handler(index, param, value) is called for normal arguments
    - default_handler(index, param, default) is called for omitted arguments
    - stararg_handler(index, param, values) is called for a "*args" argument
    """

    # deal with kwonly args
    params = pysig.parameters
    kwonly = []
    for name, p in params.items():
        if p.kind == p.KEYWORD_ONLY:
            kwonly.append(name)

    if kwonly:
        bind_args = args[: -len(kwonly)]
    else:
        bind_args = args
    bind_kws = kws.copy()
    if kwonly:
        for idx, n in enumerate(kwonly):
            bind_kws[n] = args[len(kwonly) + idx]

    # now bind
    ba = pysig.bind(*bind_args, **bind_kws)
    for i, param in enumerate(pysig.parameters.values()):
        name = param.name
        default = param.default
        if param.kind == param.VAR_POSITIONAL:
            # stararg may be omitted, in which case its "default" value
            # is simply the empty tuple
            ba.arguments[name] = stararg_handler(i, param, ba.arguments.get(name, ()))
        elif name in ba.arguments:
            # Non-stararg, present
            ba.arguments[name] = normal_handler(i, param, ba.arguments[name])
        else:
            # Non-stararg, omitted
            assert default is not param.empty
            ba.arguments[name] = default_handler(i, param, default)
    # Collect args in the right order
    args = tuple(ba.arguments[param.name] for param in pysig.parameters.values())
    return args


# Traceback (IndexError)
Traceback (most recent call last):
File "/home/ibutygin/miniconda3/envs/NUMBA_CUSTOM/lib/python3.7/site-packages/llvmlite/ir/instructions.py", line 619, in __init__
typ = typ.elements[i]
IndexError: tuple index out of range

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/home/ibutygin/src/numba/numba/numba/errors.py", line 717, in new_error_context
yield
File "/home/ibutygin/src/numba/numba/numba/lowering.py", line 260, in lower_block
self.lower_inst(inst)
File "/home/ibutygin/src/numba/numba/numba/lowering.py", line 303, in lower_inst
val = self.lower_assign(ty, inst)
File "/home/ibutygin/src/numba/numba/numba/lowering.py", line 467, in lower_assign
return self.lower_expr(ty, value)
File "/home/ibutygin/src/numba/numba/numba/lowering.py", line 932, in lower_expr
res = self.lower_call(resty, expr)
File "/home/ibutygin/src/numba/numba/numba/lowering.py", line 724, in lower_call
res = self._lower_call_normal(fnty, expr, signature)
File "/home/ibutygin/src/numba/numba/numba/lowering.py", line 903, in _lower_call_normal
res = impl(self.builder, argvals, self.loc)
File "/home/ibutygin/src/numba/numba/numba/targets/base.py", line 1132, in __call__
res = self._imp(self._context, builder, self._sig, args, loc=loc)
File "/home/ibutygin/src/numba/numba/numba/targets/base.py", line 1157, in wrapper
return fn(*args, **kwargs)
File "/home/ibutygin/src/numba/numba/numba/typing/templates.py", line 778, in method_impl
return call(builder, args)
File "/home/ibutygin/src/numba/numba/numba/targets/base.py", line 1132, in __call__
res = self._imp(self._context, builder, self._sig, args, loc=loc)
File "/home/ibutygin/src/numba/numba/numba/targets/base.py", line 1157, in wrapper
return fn(*args, **kwargs)
File "/home/ibutygin/src/numba/numba/numba/targets/imputils.py", line 193, in imp
builder, func, fndesc.restype, fndesc.argtypes, args)
File "/home/ibutygin/src/numba/numba/numba/targets/callconv.py", line 477, in call_function
args = list(arginfo.as_arguments(builder, args))
File "/home/ibutygin/src/numba/numba/numba/datamodel/packer.py", line 100, in as_arguments
for dm, val in zip(self._dm_args, values)
File "/home/ibutygin/src/numba/numba/numba/datamodel/packer.py", line 100, in <listcomp>
for dm, val in zip(self._dm_args, values)
File "/home/ibutygin/src/numba/numba/numba/datamodel/models.py", line 447, in as_argument
v = builder.extract_value(value, [i])
File "/home/ibutygin/miniconda3/envs/NUMBA_CUSTOM/lib/python3.7/site-packages/llvmlite/ir/builder.py", line 927, in extract_value
instr = instructions.ExtractValue(self.block, agg, idx, name=name)
File "/home/ibutygin/miniconda3/envs/NUMBA_CUSTOM/lib/python3.7/site-packages/llvmlite/ir/instructions.py", line 622, in __init__
% (list(indices), agg.type))
TypeError: Can't index at [0] in {}

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "test.py", line 73, in <module>
print(bar(Dummy()))
File "/home/ibutygin/src/numba/numba/numba/dispatcher.py", line 420, in _compile_for_args
raise e
File "/home/ibutygin/src/numba/numba/numba/dispatcher.py", line 353, in _compile_for_args
return self.compile(tuple(argtypes))
File "/home/ibutygin/src/numba/numba/numba/compiler_lock.py", line 32, in _acquire_compile_lock
return func(*args, **kwargs)
File "/home/ibutygin/src/numba/numba/numba/dispatcher.py", line 768, in compile
cres = self._compiler.compile(args, return_type)
File "/home/ibutygin/src/numba/numba/numba/dispatcher.py", line 77, in compile
status, retval = self._compile_cached(args, return_type)
File "/home/ibutygin/src/numba/numba/numba/dispatcher.py", line 91, in _compile_cached
retval = self._compile_core(args, return_type)
File "/home/ibutygin/src/numba/numba/numba/dispatcher.py", line 109, in _compile_core
pipeline_class=self.pipeline_class)
File "/home/ibutygin/src/numba/numba/numba/compiler.py", line 543, in compile_extra
return pipeline.compile_extra(func)
File "/home/ibutygin/src/numba/numba/numba/compiler.py", line 328, in compile_extra
return self._compile_bytecode()
File "/home/ibutygin/src/numba/numba/numba/compiler.py", line 389, in _compile_bytecode
return self._compile_core()
File "/home/ibutygin/src/numba/numba/numba/compiler.py", line 368, in _compile_core
raise e
File "/home/ibutygin/src/numba/numba/numba/compiler.py", line 359, in _compile_core
pm.run(self.state)
File "/home/ibutygin/src/numba/numba/numba/compiler_machinery.py", line 331, in run
raise patched_exception
File "/home/ibutygin/src/numba/numba/numba/compiler_machinery.py", line 322, in run
self._runPass(idx, pass_inst, state)
File "/home/ibutygin/src/numba/numba/numba/compiler_lock.py", line 32, in _acquire_compile_lock
return func(*args, **kwargs)
File "/home/ibutygin/src/numba/numba/numba/compiler_machinery.py", line 281, in _runPass
mutated |= check(pss.run_pass, internal_state)
File "/home/ibutygin/src/numba/numba/numba/compiler_machinery.py", line 268, in check
mangled = func(compiler_state)
File "/home/ibutygin/src/numba/numba/numba/typed_passes.py", line 391, in run_pass
NativeLowering().run_pass(state)
File "/home/ibutygin/src/numba/numba/numba/typed_passes.py", line 333, in run_pass
lower.lower()
File "/home/ibutygin/src/numba/numba/numba/lowering.py", line 179, in lower
self.lower_normal_function(self.fndesc)
File "/home/ibutygin/src/numba/numba/numba/lowering.py", line 220, in lower_normal_function
entry_block_tail = self.lower_function_body()
File "/home/ibutygin/src/numba/numba/numba/lowering.py", line 245, in lower_function_body
self.lower_block(block)
File "/home/ibutygin/src/numba/numba/numba/lowering.py", line 260, in lower_block
self.lower_inst(inst)
File "/home/ibutygin/miniconda3/envs/NUMBA_CUSTOM/lib/python3.7/contextlib.py", line 130, in __exit__
self.gen.throw(type, value, traceback)
File "/home/ibutygin/src/numba/numba/numba/errors.py", line 725, in new_error_context
six.reraise(type(newerr), newerr, tb)
File "/home/ibutygin/src/numba/numba/numba/six.py", line 669, in reraise
raise value
numba.errors.LoweringError: Failed in nopython mode pipeline (step: nopython mode backend)
Can't index at [0] in {}

File "test.py", line 71:
def bar(obj):
return obj.inline_method(123,456)
^

[1] During: lowering "$10call_method.4 = call $4load_method.1($const6.2, $const8.3, func=$4load_method.1, args=[Var($const6.2, test.py:71), Var($const8.3, test.py:71)], kws=(), vararg=None)" at test.py (71)

# Fixed code
def fold_arguments(pysig, args, kws, normal_handler, default_handler, stararg_handler):
    """
    Given the signature *pysig*, explicit *args* and *kws*, resolve
    omitted arguments and keyword arguments. A tuple of positional
    arguments is returned.
    Various handlers allow to process arguments:
    - normal_handler(index, param, value) is called for normal arguments
    - default_handler(index, param, default) is called for omitted arguments
    - stararg_handler(index, param, values) is called for a "*args" argument
    """

    # deal with kwonly args
    params = pysig.parameters
    kwonly = []
    for name, p in params.items():
        if p.kind == p.KEYWORD_ONLY:
            kwonly.append(name)

    if kwonly:
        bind_args = args[: -len(kwonly)]
    else:
        bind_args = args
    bind_kws = kws.copy()
    if kwonly:
        for idx, n in enumerate(kwonly):
            bind_kws[n] = args[len(kwonly) + idx]

    # now bind
    ba = pysig.bind(*bind_args, **bind_kws)
    for i, param in enumerate(pysig.parameters.values()):
        name = param.name
        default = param.default
        if param.kind == param.VAR_POSITIONAL:
            # stararg may be omitted, in which case its "default" value
            # is simply the empty tuple
            if name in ba.arguments:
                argval = ba.arguments[name]
                # NOTE: avoid wrapping the tuple type for stararg in another
                #       tuple.
                if len(argval) == 1 and isinstance(
                    argval[0], (types.StarArgTuple, types.StarArgUniTuple)
                ):
                    argval = tuple(argval[0])
            else:
                argval = ()
            out = stararg_handler(i, param, argval)

            ba.arguments[name] = out
        elif name in ba.arguments:
            # Non-stararg, present
            ba.arguments[name] = normal_handler(i, param, ba.arguments[name])
        else:
            # Non-stararg, omitted
            assert default is not param.empty
            ba.arguments[name] = default_handler(i, param, default)
    # Collect args in the right order
    args = tuple(ba.arguments[param.name] for param in pysig.parameters.values())
    return args