On Tuesday, 28 December 2021 at 18:27:36 UTC, vit wrote:
Hi, why this code doesn't compile?
```d
struct Foo{
bool opCast(T : bool)()const{
assert(0);
}
~this(){}
}
struct Bar{
const Foo foo;
}
void main(){
}
```
Error: template instance `opCast!(Foo)` does not match template
declaration `opCast(T : bool)()`
Since a destructor ignores `const`, I think adding the `~this` to
Foo manually is somehow making the compiler have to actually cast
away const, which it is doing via `cast(Foo) foo`, which fails
since you've declared your own `opCast` that only accepts
arguments implicitly convertible to `bool`.
I say this because removing the specialisation in `opCast` and
changing the return type of it to `Foo` works :
```d
struct Foo{
Foo opCast(T)()const {
assert(0);
return this;
}
~this() {}
}
struct Bar{
const Foo foo;
}
void main(){
//Bar bar = Bar(); //this will trigger the assertion failure
}
```
