[6.0] Sema: Fix existential-metatype-to-Any conversion #72808
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This reverts commit abae144.
We were incorrectly unwrapping too many levels of metatype, and our ErasureExpr would end up with conformances for the instance type and not the metatype itself. In the old universe, this was not a problem, but now Any has two protocol conformance members, so suddently this violated invariants. This was a regression, introduced in 6027bf4. Fixes rdar://125460667.
When erasing a pseudogeneric value in SILGen, we actually treat the value as if it had the type `any AnyObject`, while in Sema, it's an archetype. This requires SILGen to look up conformances again instead of using the ones in the ErasureExpr.
We should check if the type parameter actually conforms to our protocol before we do the global lookup, otherwise we might return an abstract conformance instead of an invalid conformance. I don't know if there's any way to exercise this today though.
I didn't realize it at the time, but this was actually fixed by bc85d66.
This was fixed by 6cd5468.
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@swift-ci Please test |
DougGregor
approved these changes
Apr 3, 2024
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6.0 cherry-pick of #72762 and #72789.
Description: The type checker incorrectly used the instance type of a metatype instead of the metatype itself when looking up a conformance, which caused an invariant violation in the SILCloner. This PR supersedes an earlier workaround. This PR also cherry-picks some regression tests for bugs that are already fixed on the 6.0 branch.
Scope of the issue: Various projects hit this specifically with the
any Any.TypetoAnyconversion.Origination: This was a regression since enablement of non copyable generics and didn't ship in a release.
Radar: rdar://125460667
Reviewed by: @kavon