return type and templates

[Timon Gehr]

On 11/22/2013 04:14 PM, Jonathan M Davis wrote:
> On Friday, November 22, 2013 15:20:30 Timon Gehr wrote:
>> On 11/22/2013 02:50 PM, Dicebot wrote:
>>> On Friday, 22 November 2013 at 13:43:49 UTC, Andrea Fontana wrote:
>>>> I assumed that it knows - when is trying to instatiate s.value
>>>> template - that "s.value" is part of an assignment and that it will be
>>>> assigned to an int.
>>>
>>> This is somewhat wrong part. "s.value" is distinct separate expression
>>> that must be evaluated by compiler on its own before proceeding. The
>>> fact that it is later used in assignment expression is not know at that
>>> moment.
>>
>> Lambda parameter type deduction needs to know this too.
>
> I believe that the only cases where the compiler uses the left-hand side of of
> an assignment or initialization to determine anything about the type of the
> right-hand side is when the right-hand side is a literal (be it a lambda
> literal, array literal, or some other kind of literal).
>
> - Jonathan M Davis
>


int delegate(int) dg = b?x=>x:x=>2*x;