Printing of `Expr(:thunk)`

[yuyichao]

Right now the printing of Expr(:thunk) is basically useless

julia> expand(:(for i in a end))
:($(Expr(:thunk, Toplevel LambdaInfo thunk)))

[vtjnash]

I think we should always print the full expansion of the AST instead of Toplevel LambdaInfo thunk

[ihnorton]

Seems fixed (#18413 and related)

julia> expand(Main, :(for i in a end))
:($(Expr(:thunk, CodeInfo(:(begin
        SSAValue(0) = a
        #temp# = (Base.start)(SSAValue(0))
        3:
        unless !((Base.done)(SSAValue(0), #temp#)) goto 13
        SSAValue(1) = (Base.next)(SSAValue(0), #temp#)
        i = (Core.getfield)(SSAValue(1), 1)
        #temp# = (Core.getfield)(SSAValue(1), 2)
        # meta: location REPL[2]
        #= REPL[2]:1 =#
        # meta: pop location
        11:
        goto 3
        13:
        return
    end)))))