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ed3f6b4c35
Array/ArraySlice/ContiguousArray have support for mutableSpan property. These types are "optimized COW" types, we use compiler builtins begin_cow_mutation/end_cow_mutation to optimize uniqueness checks. Since mutableSpan is a property and not a coroutine there is no way to schedule the end_cow_mutaton operation at the end of the access. This can lead to miscompiles in rare cases where we can end up using a stale storage buffer after a cow. This PR inserts end_cow_mutation_addr to avoid this issue. Note: We can end up with unnecessary end_cow_mutation_addr. But it is just a barrier to prevent invalid optimizations and has no impact.