Disallow covariant caps in the lower bound of type members
#19624
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odersky
requested changes
Feb 15, 2024
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| // Check the lower bound of path dependent types. | ||
| // See issue #19330. | ||
| val isTypeParam = t.prefix eq NoPrefix |
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isTypeParam is misleading as a name. It could also be a local type definition, that also will lead to a NoPrefix. I'd turn it around and define:
val isMember = t.prefix ne NoPrefix
odersky
requested changes
Feb 15, 2024
odersky
approved these changes
Feb 15, 2024
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Fixes #19330.
Since when instantiating a type member we do not disallow covariant
caps in the instance, a check is added at the application site to check for covariantcaps in the lower bound of type members to maintain soundness. This check is elided for type parameters since their instances are always checked at the instantiation site.