On 6/19/20 12:38 PM, SealabJaster wrote:
On Friday, 19 June 2020 at 16:31:50 UTC, Paul Backus wrote:
This is a known issue:
https://issues.dlang.org/show_bug.cgi?id=1807
"Reported: 2008"... yikes.
Thanks anyway, glad to know I wasn't just going mad :)
It's somewhat difficult to solve, because reverse-templating is not
necessarily one-to-one, or even have any tractible relationship at all.
Consider, for instance:
struct Foo(T) {}
alias Bar(T) = Foo!int;
void takefoo(X)(Bar!X) {}
takefoo(Foo!int());
How does the compiler decide what type T should be? It could be anything.
But this could be special cased for a *direct* alias translation. How to
define that is tricky, but should match the pattern:
alias Template1(T) = Template2!(T, and, possibly, other, things)
Where Template2!(T, and, possibly, other, things) can be deduced for
Template2 and T using IFTI directly.
As the age of that bug report shows, it's not easy to define or solve.
-Steve
