Record ordering constraint between HK type variables #9733
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odersky
approved these changes
Sep 10, 2020
If `?F <: [X] => ?G[X]`, then the ordering part of the constraint should record `?F <: ?G`, otherwise constraints won't be propagated correctly. It's not clear to me if we should make a similar change in `stripParams` but note that doing so would require being a bit careful: since we use the upper bound of a type variable to determine its kind, we can't just replace it by `[X] => ?G[X]` by `AnyKind`. Fixes scala#9676.
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(Merging, community build failure is due to flaky test and is being taken care of elsewhere: #9784) |
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If
?F <: [X] => ?G[X], then the ordering part of the constraint shouldrecord
?F <: ?G, otherwise constraints won't be propagated correctly.It's not clear to me if we should make a similar change in
stripParamsbut note that doing so would require being a bit careful: since we use
the upper bound of a type variable to determine its kind, we can't just
replace it by
[X] => ?G[X]byAnyKind.Fixes #9676.