return unfixed len if pat has reported error

[bvanjoi]

• Fixes ICE: expected usize, got UnevaluatedConst #116186
• Fixes ICE: expected usize, got Const #113021

This issue arises due to the creation of a fixed-length pattern, as a result of the mir body corruption. The corruption taints tcx.eval_to_allocation_raw, causing it to return AlreadyReported. Consequently, this prevents len.try_eval_target_usize from evaluating correctly and returns None. Lastly, it results in the return of [usize; min_len].

To rectify this issue, my approach is that to return unfixed when encountering ErrorHandled::Reported. Additionally, in instances of ErrorHandled::TooGeneric, the previous logic has been reinstated.

[rustbot]

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[bvanjoi]

I had just discovered a PR(#113712) to solve similar problems and this comment, therefore I'm drawing the attention of @oli-obk to this PR.

[bvanjoi]

I believe this PR also addresses #113021. However, since the test cases are mostly the same, I will refrain from adding an extra case.

[oli-obk]

Yea, this lgtm as a fix. It propagates the error instead of dropping it on the floor.

[oli-obk]

@bors r+ rollup

Thanks!

[bors]

📌 Commit 6de40ab has been approved by oli-obk

It is now in the queue for this repository.