Inconsistent error messages when returning the wrong type for the type-conversion magic methods

Bug report

Bug description:

I noticed the error messages between magic methods like __int__ and __float__ were inconsistent. This seems like slightly undesirable behavior to me. I used the following code to generate many of them.

class Foo:
    def __int__(self):
        return None
    
    def __float__(self):
        return None
    
    def __bytes__(self):
        return None
    
    def __complex__(self):
        return None
    
    def __bool__(self):
        return None
    
    def __str__(self):
        return None

try:
    int(Foo())
except Exception as e:
    print(e)

try:
    float(Foo())
except Exception as e:
    print(e)

try:
    bytes(Foo())
except Exception as e:
    print(e)

try:
    complex(Foo())
except Exception as e:
    print(e)

try:
    bool(Foo())
except Exception as e:
    print(e)

try:
    str(Foo())
except Exception as e:
    print(e)

And the output is as follows:

__int__ returned non-int (type NoneType)
Foo.__float__ returned non-float (type NoneType)
__bytes__ returned non-bytes (type NoneType)
__complex__ returned non-complex (type NoneType)
__bool__ should return bool, returned NoneType
__str__ returned non-string (type NoneType)

The first issue I've made, but seems like a reasonable bug. I'm not sure if there are other "type-conversion" magic methods out there that aren't consistent.

CPython versions tested on:

3.13, 3.12

Operating systems tested on:

Windows

Linked PRs

• gh-130835
• gh-144737
• gh-144827
• gh-151894
• gh-154606
• gh-156080
• gh-156120

Start by running the issue's reproducer and comparing the reported messages for each type-conversion magic method. Review the linked PRs to determine which cases are already addressed and what remains; done means the relevant error messages have an agreed, consistent behavior with regression coverage.