struct Example {
int opApply(int delegate(int x) dlg) const {
return dlg(0);
}
}
Example.opApply now cannot be used in a @nogc context, even
though it is fully @nogc whenever dlg is.
Ditto with nothrow, pure, @safe and other attributes.
For a large code-base containing higher-order functions, this
makes use of these attributes nearly impractical.
What I would like to say is something like:
struct Example {
int opApply(int delegate(int x) dlg G?@nogc T?nothrow P?pure)
const @G @T @P {
return dlg(0);
}
}
The above would assign G to @nogc or nothing, according to
whether the delegate is.
Ditto with T and nothrow, P and pure.
Then they can be used freely in other parts of the type signature.
Unlike templates, these would not require any generated code
duplication (they're just for type-checking, after all).
Fixing this along-side the more minor issue of many standard
libraries lacking proper annotations -- would make @nogc, pure
and nothrow much more practical.
