Heal occurrences of => T between ElimByName and Erasure #19558
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There's a window of vulnerability between ElimByName and Erasure where some ExprTypes `=> T` that appear as parameters of function types are not yet converted to by-name functions `() ?=> T`. These would cause an assertion violation when used as operands of & or |. We fix this on the fly when forming these types in TypeComparer. As explained in ElimByName, we can't fix it beforehand by mapping all occurrences of `=> T` to `() ?=> T` since that could lead to cycles. Fixes scala#19548
Avoids follow-up failures in Ycheck for the test case.
szymon-rd
approved these changes
Jan 29, 2024
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There's a window of vulnerability between ElimByName and Erasure where some ExprTypes
=> Tthat appear as parameters of function types are not yet converted to by-name functions() ?=> T. These would cause an assertion violation when used as operands of & or |. We fix this on the fly when forming these types in TypeComparer. As explained in ElimByName, we can't fix it beforehand by mapping all occurrences of=> Tto() ?=> Tsince that could lead to cycles.Fixes #19548