Differentiate Scala 2 and Scala 3 wildcard identifier names #9614
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This change names wildcards written with Scala 3 `?` syntax with `?$N` pattern instead of `_$N` used for Scala 2 wildcards There are two reasons for it: - To allow `kind-projector` to implement Scala 3 underscore syntax for type lambdas by transforming old-style underscores, but leaving Scala 3 underscores intact - To show a mildly more relevant error message, since a wildcard introduced by `?` will now also have a name with `?` in the error message
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This change is required together with #9605 to implement typelevel/kind-projector#188 |
lrytz
approved these changes
May 10, 2021
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This change names wildcards written with Scala 3
?syntax with?$Npattern instead of_$Nused for Scala 2 wildcardsThere are two reasons for it:
kind-projectorto implement Scala 3 underscore syntax for type lambdas by transforming old-style underscores, but leaving Scala 3 underscores intact?will now also have a name with?in the error messageSee also:
_as a placeholder and?as wildcard? typelevel/kind-projector#120