DIP 1016--ref T accepts r-values--Formal Assessment

[12345swordy]

On Wednesday, 30 January 2019 at 18:29:37 UTC, Manu wrote:
> On Wed, Jan 30, 2019 at 9:20 AM Neia Neutuladh via 
> Digitalmars-d-announce <digitalmars-d-announce at puremagic.com> 
> wrote:
>>
>> On Wed, 30 Jan 2019 09:15:36 -0800, Manu wrote:
>> > Why are you so stuck on this case? The DIP is about 
>> > accepting rvalues,
>> > not lvalues...
>> > Calling with 'p', an lvalue, is not subject to this DIP.
>>
>> The result of a CastExpression is an rvalue. An implicit cast 
>> is a compiler-inserted CastExpression. Therefore all lvalues 
>> with a potential implicit cast are rvalues.
>
> But there's no existing language rule that attempts to perform 
> an
> implicit cast where an lvalue is supplied to a ref arg...?
> Why is the cast being attempted?
Because of the rewrite that your proposed in your dip.

void fun(ref int x);

fun(10);

{
   T __temp0 = void;
   fun(__temp0 := 10);
}

lets replace 10 with a short variable named: S

void fun(ref int x);

fun(S)
{
   T __temp0 = void;
   fun(__temp0 := S);
}
fun(__temp0 := S) This is where the cast is being attempted. As 
__temp0 is an                            integer type and S is a 
short type