A lint for large stack allocation

[cramertj]

Stack allocation of large arrays, such as [0; 8388608] should be an error-- they will cause stack overflows.

[llogiq]

Is this still true? I thought we were already resizing the stack when needed. Am on mobile right now, but will check.

[cramertj]

I just tried it on the latest nightly and got an overflow.

[llogiq]

OK then. Perhaps it makes sense to check stack sizes on a number of systems first so we can report on what systems an allocation would certainly fail?

[cramertj]

I believe the minimum stack size is available via the environmental variable RUST_MIN_STACK

[llogiq]

I know. However the value of that variable varies from system to system. For some, 'it runs on my machine' may be OK, but many folks I know want their code to run on other systems, too (or at least aren't directly opposed to that)...

[cramertj]

Right-- I was just pointing it out as an easy way to check the maximum size on different systems.

[basil-cow]

@flip1995 I suggest closing this in favor of #4520, as it has more recent and relevant info.