On 12/09/2012 13:55, Nick Treleaven wrote:
On 12/09/2012 13:39, Nick Treleaven wrote:
class Bar { int b; }
void changeBar(ref Bar b) { b = new Bar(); }
void warning()
{
Bar bar = new Bar();
bar.b = 10;
bar.changeBar(); // Warning: 'bar' is implicitly passed by
reference. To eliminate this warning, use 'changeBar(ref bar)' instead
or do not compile with '-callSiteRef'
}
Again, this problem only applies to classes, since it is understood that
structs are normally passed by reference.
I had only thought about UFCS and ref parameters for value types. You
are right that requiring callsite ref for class ref parameters would be
a useful idea, as modifying the ref itself is unusual behavior. And
because of that, disallowing UFCS for functions that have a class ref
parameter as the first parameter might be an elegant solution.
Also the same applies to ref parameters with any reference types:
On 08/09/2012 14:05, Chris Nicholson-Sauls wrote:
> void func (ref int[], int)
>
> If ref/out were required at the call site, this destroys UFCS.
>
> int[] array;
> array.func(0); // error, ref not specified by caller
So the above poster was right
Ignore that last reply, slices are value types. The syntax array.func()
looks like it might modify array's contents and/or length, so UFCS is
OK. It is only ref class and ref pointer arguments that UFCS should be
disallowed on to enforce call-site ref.
