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.
