Display regression in assignment to composite type field

[omus]

While updating the doctests I found, what I believe to be, a regression:

Julia 0.4.6

julia> type Foo
         bar
         baz::Int
         qux::Float64
       end

julia> foo = Foo("Hello, world.", 23, 1.5)
Foo("Hello, world.",23,1.5)

julia> foo.qux = 2
2.0

julia> foo.qux
2.0

Julia 0.5-dev

...

julia> foo.qux = 2  # Should be print 2.0 since `qux` is a Float64 field
2  

julia> foo.qux
2.0

Apologies if this has been discussed elsewhere.

[omus]

cc: @tkelman (we discussed this earlier today)

[yuyichao]

The change is a bug fix. a.b = c is supposed to return c.

[yuyichao]

(Also this has nothing to do with displaying....)

Ref #15753 (comment) and #14691

[tkelman]

whoops, thanks @yuyichao for having a better memory on this one than I did

[StefanKarpinski]

This behavior probably deserves a FAQ entry at this point.

[omus]

I've been re-reading the documentation and making corrections. If I find a good spot to mention this behavior I'll add something in.