update error E0450 to new format

[mikhail-m1]

Fixes#35925 as part of #35233.

I've solve the bonus, and I wonder if any simpler way to do this. But may be possible simplify if let expressions?

r? @jonathandturner

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[sophiajt]

Looks good! There may be a nicer way to do this, but this looks fine to me.

@bors r+ rollup

[bors]

📌 Commit 9c07ed2 has been approved by jonathandturner