Mypy was designed to enable gradual adoption. There is definitely Python code out there with `def f(i=0)` where `i` could be any numeric type including floats,

Mypy was designed to enable gradual adoption. There is definitely Python code out there with `def f(i=0)` where `i` could be any numeric type including floats, complex, numpy etc.. This is called duck typing. It's wrong for a type checker to assume `i: int` in such a case. Pyright probably works if you use it for a new project from the start or invest a lot of time "fixing" an existing project. But it's a totally different tool and it's silly to criticise mypy without understanding its use case.