[Issue 15982] std.array.array treats dynamic arrays as input ranges and allocates new memory

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=15982

--- Comment #5 from ag0aep6g at gmail.com ---
(In reply to sigod from comment #4)
> I bet no one uses `array()` for duplicating
> arrays.

I don't think betting on these things is a good course of action. The function
is documented to allocate a new array. Changing that is a breaking change.

> Function called `array` for a reason. Because it gives you array where you
> have only an input range. It doesn't make sense to do anything if you
> already have an array. In normal code you will never call `array` for array.

Here's a little generic function that relies on std.array.array's current
behavior:
----
immutable(ElementType!R)[] toImmutableArray(R)(R range)
    if (isInputRange!R && !hasIndirections!(ElementType!R))
{
    import std.array: array;
    import std.exception: assumeUnique;
    return assumeUnique(range.array);
}
----

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