Consider an `__eq__` that always raises as non-overlapping for equality purposes?

Feature

When a class defines __eq__, Mypy understandably bails out of ever considering that class as statically non-overlapping with another.

IOW,

class A:
   pass

class B:
   pass

A() == B()

goes error: Non-overlapping equality check (left operand type: "A", right operand type: "B") [comparison-overlap], as you'd expect, but

class A:
   def __eq__(self, other: object) -> bool:
       raise RuntimeError("Please do not directly compare A objects; use special method önnönnöö()")

   def önnönnöö(self, other: A | B) -> bool:
       return False  # some specific Explicit Is Better Than Implicit logic here

class B:
   pass

A() == B()

has no errors mypy could see.

It would be useful if mypy could recognize that an __eq__ function that always raises (or, I suppose, more broadly, can never return a value) makes a class never overlap with any other class.

La issue riguarda la diagnostica comparison-overlap di mypy e la gestione di eq di Python. Inizia individuando l’implementazione e i test di comparison-overlap, quindi analizza come si potrebbe riconoscere un eq che solleva sempre un’eccezione. Il lavoro è completato quando l’esempio mostrato di A e B viene gestito come un controllo di uguaglianza senza sovrapposizione, senza indebolire le diagnostiche esistenti.