Fix SCF loop type inference with bounded widening - #730

from typing import Any
from kirin.dialects import ilist
from kirin.passes import TypeInfer
from kirin.prelude import structural_no_opt
from kirin.rewrite import Walk

@structural_no_opt
def identity(x: int) -> int:
    return x

@structural_no_opt
def grow(n: int) -> ilist.IList[int, Any]:
    xs = ilist.IList([])
    for _ in range(n):
        xs = xs + [4]
        xs = ilist.map(identity, xs)
    return xs

print("Before passes:", list(grow(3)))

TypeInfer(grow.dialects, no_raise=False)(grow)
print("After TypeInfer:", list(grow(3)))

Walk(ilist.rewrite.Unroll()).rewrite(grow.code)
print("After Unroll:", list(grow(3)))