On Thursday, 24 January 2019 at 07:18:58 UTC, Mike Parker wrote:
Walter and Andrei have declined to accept DIP 1016, "ref T
accepts r-values", on the grounds that it has two fundamental
flaws that would open holes in the language.
fun(10)
==>
{
T __temp0 = void;
fun(__temp0 := 10);
}
the rewrite is from an expression to a statement, rendering it
invalid.
if the first constructor throws an exception, all remaining
values will be destroyed in the void state as they never have
the chance to become initialized.
They say that with the current semantics, this function only
operates on long values as it should. With the proposed
semantics, the call will accept all shared integral types.
I think this solves all of the above:
fun(10);
==>
(int __temp0){ (return)? fun( __temp0 ); }(10);
-The expression/statement issue is solved by the closure
-The initialization issue created by the ":=" approach is not
present here
-For this rewrite, 'T' is the type of the rvalue argument, not
the type of the function parameter. This prevents undesired
implicit conversions.
