On 04/02/2018 10:59 AM, ag0aep6g wrote:
That wouldn't be possible if `innocent` were only head-mutable in the
postblit function, instead of fully mutable as it is currently (bug).
`innocent` would be typed as `immutable(int)[]`, and you could not
assign it to the fully mutable `sneaky`.
Problem is we don't have head-mutable in the language. Yes, for built-in
slices the mechanism is simple - just change qualifier(T[]) to
qualifier(T)[]. For a struct S, there is no way to convert from
qualifier(S) to tailqualifier(S).
I plan to attack this directly in the DIP - provide a way for structs to
express "here's what implicit conversion should be applied when doing
template matching".
Andrei
