DIP 1016 should use expression lowering, not statement lowering

[Andrei Alexandrescu]

While writing this example:

int[] a = cast(int[]) alloc.allocate(100 * int.sizeof);
if (alloc.reallocate(a, 200 * int.sizeof))
{
     assert(a.length == 200);
}

=====>

int[] a = cast(int[]) alloc.allocate(100 * int.sizeof);
void[] __temp0 = a;
if (alloc.reallocate(__temp0, 200 * int.sizeof)
{
     assert(a.length == 200);
}

I noticed a problem - the lowering as informally described in DIP 1016 
makes it difficult to figure how function calls present in control 
statements like if, while, etc. should behave. Where should the 
temporary go? An expression-based lowering clarifies everything. A 
statement-based lowering would need to work on a case basis for all 
statements involving expressions.


Andrei