On Thursday, 28 June 2012 at 04:43:07 UTC, BLM768 wrote:
On Monday, 25 June 2012 at 20:06:21 UTC, Tobias Pankrath wrote:
---------
struct A { bool a; alias a this; }
struct B { int b; alias b this; }
A a = false; // works
B b = 12; // works
struct C
{
A aa;
B ab;
}
C c = { false, 12 }; // does not work, because the implicit
conversion does not happen.
-----
What is the reason to allow the first two assignments? Isn't
it just another implicit conversion that shouldn't be allowed?
The compiler isn't "smart" enough to realize that you're trying
to use an implicit conversion. It's only told to expect the
conversion in certain situations, such as assignment, and
getting it to work for rarer cases would involve patching it
with more special-case code. The initializer is also expecting
struct _values_; I don't think that you could call a function
that wants an A and give it a bool, either. Making a struct
value from an expression and initializing a struct in a
definition are subtly different and follow different codepaths
in the compiler.
I'm fine that the assignment to C is verboten. I'd disallow the
first assignments to and would like to know, why they are kept.
