problem with tuple+obj and list+obj expressions

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
25/100
Issue type
Bug
Clarity
Needs clarification
Activity status
Stale
Tech stack
javascript, python
Domain
compilers

Research direction

No source file or test is named. Start by reproducing the supplied Transcrypt Python snippet in the stated Python 3.9 and Firefox environment, then trace operator dispatch in the compiler. Done means tuple/list operations correctly honor the operand's reflected methods, including the reported addition and multiplication cases.

Written by the indexing model from the issue text.

Description

There is an apparent problem with tuple + obj and list + obj expressions. Rather than call obj.__radd__, it seems that tuple.__add__/list.__add__ are called. Similar problem occurs with tuple * obj and list * obj. Problem appears to stem from the fact that tuple and list have __add__ and __mul__ methods that seem to take priority.

python code:

# __pragma__ ('opov')

class Obj:
    def __init__(self, x, y):
        self.x = x
        self.y = y
        self._message = None
    def __str__(self):
        return 'obj'
    def __add__(self, other):
        self._message = 'obj.__add__'
        return (self.x + other[0], self.y + other[1])
    def __sub__(self, other):
        self._message = 'obj.__sub__'
        return (self.x - other[0], self.y - other[1])
    def __radd__(self, other):
        self._message = 'obj.__radd__'
        return (other[0] + self.x, other[1] + self.y)
    def __rsub__(self, other):
        self._message = 'obj.__rsub__'
        return (other[0] - self.x, other[1] - self.y)
    @property
    def message(self):
        message = self._message
        self._message = None
        return message

obj = Obj(4, 2)
_tuple = (4, 2)
_list = [4, 2]

print('obj + tuple:', obj + _tuple, '\t\tcalled:', obj.message)
print('obj - tuple:', obj - _tuple, '\t\tcalled:', obj.message)
print('tuple + obj:', _tuple + obj, '\tcalled:', obj.message)
print('tuple - obj:', _tuple - obj, '\t\tcalled:', obj.message)
print('obj + list:', obj + _list, '\t\tcalled:', obj.message)
print('obj - list:', obj - _list, '\t\tcalled:', obj.message)
print('list + obj:', _list + obj, '\tcalled:', obj.message)
print('list - obj:', _list - obj, '\t\tcalled:', obj.message)

console output:

obj + tuple: (8, 4) 		called: obj.__add__
obj - tuple: (0, 0) 		called: obj.__sub__
tuple + obj: [4, 2, obj] 	called: None
tuple - obj: (0, 0) 		called: obj.__rsub__
obj + list: (8, 4) 		called: obj.__add__
obj - list: (0, 0) 		called: obj.__sub__
list + obj: [4, 2, obj] 	called: None
list - obj: (0, 0) 		called: obj.__rsub__

env: Python3.9 venv with pip install Transcrypt
testing: Firefox version 133 in Linux

Dominant language
Python
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