Clean up kindedness tests #4360
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smarter
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Apr 29, 2018
| case tree: TypeApply => | ||
| val tree1 @ TypeApply(fn, args) = normalizeTypeArgs(tree) | ||
| Checking.checkBounds(args, fn.tpe.widen.asInstanceOf[PolyType]) | ||
| if (fn.symbol != defn.ChildAnnot.primaryConstructor) { |
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Instead of special-casing Child, the compiler could be changed to always use it with fully-applied types with wildcards, e.g. Child[Cons[_]]
We currently mostly use isLambdaSub which detects unapplied abstract and alias types but not unapplied generic classes. We should use `hasHigherKind` more often, which includes unapplied classes. The first commit fixes a problem with `hasHigherKind` where abstract types upper bounded by `AnyKind` where not classified as higher-kinded. It also changes checkSimpleKinded to use hasHigherKind instead if isLambdaSub.
Also disallow unapplied classes if bounds are first-kinded. This broke the Child annotation which should really be kind polymorphic. Fixed for now by making a special exception for Child.
hasHigherKind is misleading since it will cover AnyKind and Effect as well and it is not clear how these are "higher" kinds.
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Blaisorblade
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This follows scala#4360. I'd love to add a test but scala#4360 has none, so I'm not 100% sure what it'd look like.
Blaisorblade
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This follows scala#4360. I'd love to add a test but scala#4360 has none, so I'm not 100% sure what it'd look like.
Blaisorblade
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This follows scala#4360. I'd love to add a test but scala#4360 has none, so I'm not 100% sure what it'd look like.
Blaisorblade
added a commit
to dotty-staging/dotty
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Aug 16, 2018
This follows scala#4360. I'd love to add a test but scala#4360 has none, so I'm not 100% sure what it'd look like.
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We currently mostly use isLambdaSub which detects unapplied
abstract and alias types but not unapplied generic classes.
We should use
hasHigherKindmore often, which includesunapplied classes.
The first commit fixes a problem with
hasHigherKindwhereabstract types upper bounded by
AnyKindwhere not classifiedas higher-kinded.
It also changes checkSimpleKinded to use hasHigherKind instead
if isLambdaSub.
I thought it would be good to get this in before I proceed with effects, since
effects effectively introduce another kind.