Use inout for ref returning members in std.container.array

[nordlow]

For motivation see

http://forum.dlang.org/thread/agyeejbrpotpjrecepyl@forum.dlang.org#post-wysehvbsfnezfozsagpl:40forum.dlang.org

[quickfur]

What about unittests that call these functions with mutable/immutable arguments? I'd like something to fail if somebody inadvertently removes these inouts.

[nordlow]

Ok. I added tests for opIndex(), back() and front(). Neither compile if I remove the inout qualifiers for the respective function.

If there are more functions in other containers I can make them inout too. If so should I do that in this PR or others?

BTW:

    const Array!int a = [0];
    foreach (e; a) {}

errors as

array.d(860,5): Error: template std.array.popFront cannot deduce function from argument types !()(const(Array!int)), candidates are:
/home/per/opt/x86_64-unknown-linux-gnu/dmd/linux/bin64/src/phobos/std/array.d(573,6):        std.array.popFront(T)(ref T[] a) if (!isNarrowString!(T[]) && !is(T[] == void[]))
/home/per/opt/x86_64-unknown-linux-gnu/dmd/linux/bin64/src/phobos/std/array.d(596,6):        std.array.popFront(C)(ref C[] str) if (isNarrowString!(C[]))

because of const qualifier of a. Could this be made to work somehow?

[quickfur]

Shouldn't a slice of the Array be taken when iterating over it? At least, that's what I thought it should do. Const/immutable built-in arrays can't be iterated over either, because popping an array (slice) modifies it. In the built-in case, though, foreach works because it implicitly makes a slice of the array, changing it from const(T[]) to const(T)[].

[nordlow]

Added inout support for range aswell along with unittests.

[quickfur]

LGTM, thanks!

[quickfur]

Auto-merge toggled on

[JakobOvrum]

I don't think this works when T in Array!T has mutable indirection. Unfortunately, constifying opSlice is not a satisfying solution to this problem.

[schuetzm]

See also: http://forum.dlang.org/thread/ijenovsipdqstykmkvlw@forum.dlang.org

[MartinNowak]

Any fix in sight?
Issue 13621 – inout issue with std.container.Array opSlice

[mihails-strasuns]

#2643

[nordlow]

I propose to close this in favour of #2631.