Fix Issue 21956 - ice on foreach over an AA of noreturn

[RazvanN7]

The backend does not know how to treat assignments where the rhs is a noreturn expression. And that is probably fine since such expressions should be replaced with assert(0).

For each statements over noreturn arrays, the compiler ends up generating el = __r[idx], therefore trying to assign a noreturn expression. With this patch, the mentioned assignment is replaced with assert(0).

I'm targeting master because this is the first step to unblock dlang/phobos#8283

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Bugzilla references

Auto-close	Bugzilla	Severity	Description
✓	21956	critical	ice on foreach over an AA of noreturn

⚠️⚠️⚠️ Warnings ⚠️⚠️⚠️

• Regression or critical bug fixes should always target the stable branch. Learn more about rebasing to stable or the D release process.

To target stable perform these two steps:

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Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub run digger -- build "master + dmd#14274"

[thewilsonator]

ICEs go to stable

[RazvanN7]

I'm targeting master because this is the first step to unblock dlang/phobos#8283

Also, noreturn is just half implemented. If I were to decide, I would have put it behind a preview switch. Anyway, I have more fixes for noreturn on my pipeline and it would be easier to put them in master.

[RazvanN7]

cc @dkorpel . Is this in line with the DIP?

[ibuclaw]

ICEs go to stable

Probably need an ltsstable branch soon too. :-)