https://issues.dlang.org/show_bug.cgi?id=24018

--- Comment #1 from FeepingCreature <default_357-line@yahoo.de> ---
I think the underlying problem is maybe actually that `.length =` does default construction. There is no way to change length at once without "constructing" the target memory, but that's what `_d_arraycatnTX` requires.

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https://issues.dlang.org/show_bug.cgi?id=24018

Teodor Dutu <teodor.dutu@gmail.com> changed:

           What    |Removed                     |Added
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                 CC|                            |teodor.dutu@gmail.com

--- Comment #2 from Teodor Dutu <teodor.dutu@gmail.com> ---
The old hook was using `__arrayAlloc()` and `__setArrayAllocLength()` to
allocate the resulting array. I am trying to move them to core.lifetime.d as
templates now as part of https://github.com/dlang/dmd/pull/15299. After this,
I'll update `_d_arraycatnTX()` to use them instead of `.length = ...`.

I can't just import them from rt.lifetime.d to core.lifetime.d because the build system doesn't allow this dependency. And core.lifetime.d is never compiled, so it can only contain templates. I gave more details about this issue in this post: https://github.com/dlang/dmd/pull/15299

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https://issues.dlang.org/show_bug.cgi?id=24018

Dlang Bot <dlang-bot@dlang.rocks> changed:

           What    |Removed                     |Added
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           Keywords|                            |pull

--- Comment #3 from Dlang Bot <dlang-bot@dlang.rocks> ---
@FeepingCreature created dlang/dmd pull request #15352 "CHANGE: Make `array.length = n` `@system` if default construction is disabled on the array type (fixes 24018)" fixing this issue:

- Fix issue 24018: make `array.length = n` `@system` if default construction is
disabled on the array type.
  This is needed as there is otherwise no good way to resize an array of
non-constructable elements in user code at all.

https://github.com/dlang/dmd/pull/15352

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https://issues.dlang.org/show_bug.cgi?id=24018

--- Comment #4 from Dlang Bot <dlang-bot@dlang.rocks> ---
@FeepingCreature created dlang/dmd pull request #15354 "Fix issue 24018: set length manually via runtime function." fixing this issue:

- Fix issue 24018: make `array.length = n` `@system` if default construction is
disabled on the array type.
  This is needed as there is otherwise no good way to resize an array of
non-constructable elements in user code at all.

- Fix issue 24018: instead of calling `array.length =`, call the runtime
function that implements `array.length =` instead.
  This skips the check for the element type being constructable, which is
correct because concatenation doesn't expose unconstructed memory anyway.

https://github.com/dlang/dmd/pull/15354

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https://issues.dlang.org/show_bug.cgi?id=24018

Dlang Bot <dlang-bot@dlang.rocks> changed:

           What    |Removed                     |Added
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             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #5 from Dlang Bot <dlang-bot@dlang.rocks> ---
dlang/dmd pull request #15354 "Fix issue 24018: set length manually via runtime function." was merged into master:

- f17d270cacabbb192c9f01a2aecd10e1389fcf8e by Mathis Beer:
  Fix issue 24018: make `array.length = n` `@system` if default construction is
disabled on the array type.
  This is needed as there is otherwise no good way to resize an array of
non-constructable elements in user code at all.

- e37e3f18844494166ac3b68f2b5b6bf450867712 by Mathis Beer:
  Fix issue 24018: instead of calling `array.length =`, call the runtime
function that implements `array.length =` instead.
  This skips the check for the element type being constructable, which is
correct because concatenation doesn't expose unconstructed memory anyway.

https://github.com/dlang/dmd/pull/15354

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