Add check if ty has_escaping_bound_vars in zero_sized_map_values lint

[DevinR528]

Fixes: #7447

changelog: fix ICE in [zero_sized_map_values]

[rust-highfive]

r? @flip1995

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[DevinR528]

Not exactly sure if this is the best way, it seems that checking for Cow here would also work but the way it is now, seems more robust since that is the method call causing the ICE?

This also fails so Cow wouldn't work struct Foo<'a>(Cow<'a, whatever>)

[flip1995]

I think this is a more general problem in Clippy. The same error with layout_of happened to me yesterday, when I did the rustup. The fix was the same. Clippy has about 20 calls to layout_of. So maybe we should implement a utils function for this, which calls has_escaping_bound_vars before calling layout_of?

[flip1995]

Let's ask about it: rust-lang/rust#86867 (comment)

[DevinR528]

Cool in a day or so I can just preemptively add this to all the layout_of calls, but I will follow the conversation in the rust repo.

[flip1995]

can just preemptively add this to all the layout_of calls,

Yeah. Or better: implement a clippy_utils::layout_of, that looks like this:

fn layout_of(cx: LateContext, ty: Ty) -> Option<_> {
    if ty.has_escaping_bound_vars() {
        return None;
    }
    cx.tcx.layout_of(ty)
}

If you don't have time for it, let me know and I'll do this tomorrow. We have to sync back those fixes before the release in 1 and a half weeks.

[flip1995]

Since we didn't get any more reports on this, I'm holding off from replacing all of the layout_of calls for now. I have a patch ready here: https://github.com/flip1995/rust-clippy/tree/layout_of-util

@bors r+

[bors]

📌 Commit 7312611 has been approved by flip1995

[bors]

⌛ Testing commit 7312611 with merge f467750...

[bors]

☀️ Test successful - checks-action_dev_test, checks-action_remark_test, checks-action_test
Approved by: flip1995
Pushing f467750 to master...

[DevinR528]

Cool thanks! Sorry I didn't get around to it I was doing a bit more traveling than I thought I'll keep an eye on any ICE that could be related.