Closure lowering error

[yuyichao]

This is what's causing #18156 (comment) after #18130. I assume @tkelman have already figured out the cause but I don't think there's an open issue for it.

Reduced test case.

function do_test(body)
    try
        body()
    end
end
function f()
    do_test(()->successflag)
    successflag = false
end

f()

Results in an UndefVarError since the closure construction want to access successflag before it is defined.

Lowered IR

begin 
        nothing
        #3 = $(Expr(:new, :((Core.apply_type)(Main.##3#4,(Core.typeof)(successflag))), :(successflag)))
        SSAValue(0) = #3
        (Main.do_test)(SSAValue(0)) # line 11:
        successflag = false
        return false
end