Bug 22982 – Can't copy scope range elements into a returned array

This code should, but doesn't, compile: --------------------- void main() @safe pure { import std.range : only; scope rng = only("foo", "bar"); oops(rng); } auto oops(Range)(return scope Range range) @safe { import std.range : ElementEncodingType; ElementEncodingType!Range[] result; foreach(e; range) result ~= e; return result; } ------------------------ d.d(13): Error: scope variable `e` may not be copied into allocated memory d.d(6): Error: template instance `d.oops!(OnlyResult!(string, string))` error instantiating

The `only` range here is essentially a static array of `scope` strings. You can't put scope strings in a dynamic array, because `scope` semantics aren't transitive, so the error is correct.

I don't know if transitivity has anything to do with it, since the element is scope. Conceptually, I think return scope on `only` should allow me to return an array from it.

(In reply to Atila Neves from comment #2) > I don't know if transitivity has anything to do with it, since the element > is scope. > > Conceptually, I think return scope on `only` should allow me to return an > array from it. `scope` is not a type qualifier. You cannot have a dynamic array of `scope` things. `scope` always applies to the outermost indirection(s) of a variable (ignoring `ref`). If you think `scope` should work differently, you will probably have to re-design the whole thing.