Bug lowering `scf.IfElse`

[weinbe58]

The following lowering doesn't look right to me:

from kirin.prelude import structual

@structural
def test(cond: bool) -> int:
    c = 0
    if cond:
        c = 1
    else:
        return 2
        
    return c

currently lowers to:

func.func @test(cond : !py.bool) -> !py.int {
  ^0(%test_self, %cond_1):
  │    %c = py.constant.constant 0 : !py.int
  │ %cond = scf.if %cond_1 : !py.bool {
  │         │ ^1(%cond_2):
  │         │ │ scf.yield %cond_2 : !py.bool
  │         } else {
  │         │ ^2(%cond_3):
  │         │ │ %0 = py.constant.constant 2 : !py.int
  │         │ │      func.return %0
  │         } -> purity=False
  │         func.return %c
} // func.func test

shuold be something more like:

func.func @test(cond : !py.bool) -> !py.int {
  ^0(%test_self, %cond_1):
  │    %c = py.constant.constant 0 : !py.int
  │ %cond, %c_1 = scf.if %cond_1 : !py.bool {
  │                  │ ^1(%cond_2):
  │                  │ │ %c_2 = py.constant 1
  │                  │ │ scf.yield %cond_2 : !py.bool, %c_2 : !py.int
  │                  } else {
  │                  │ ^2(%cond_3):
  │                  │ │ %0 = py.constant.constant 2 : !py.int
  │                  │ │      func.return %0
  │                  } -> purity=False
  │         func.return %c_1
} // func.func test

[david-pl]

@weinbe58 duplicate of #416 ? At least, when running this on the branch of #417 , I get:

func.func @test(cond : !py.bool) -> !py.int {
  ^0(%test_self, %cond_1):
  │ %cond, %c = scf.if %cond_1 : !py.bool {
  │             │ ^1(%cond_2):
  │             │ │ %c_1 = py.constant.constant 1 : !py.int
  │             │ │        scf.yield %cond_2 : !py.bool, %c_1
  │             } else {
  │             │ ^2(%cond_3):
  │             │ │ %0 = py.constant.constant 2 : !py.int
  │             │ │      func.return %0
  │             } -> purity=False
  │             func.return %c
} // func.func test