Inconsistent "return value" of assignment for type fields

[rfourquet]

Quoting @JeffBezanson :

= returns the right-hand side every time. No exceptions. That ought to be consistent enough for anybody.

But:

julia> type A; a::UInt end
julia> A(0).a = 0
0x0000000000000000

I couldn't find the above stated rule in the manual, if it isn't this should be added before closing this issue (cf. #7341 (comment)).