[CSBindings] Limit BindingSet::isViable binding skipping to stdlib …
#77153
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…collection types This is follow-up to swiftlang#76487 It's reasonable to coalesce bindings of different kind if they don't allow implicit conversions like stdlib collection types do. Resolves: swiftlang#77003
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@swift-ci please test |
| if (existing->Kind != binding.Kind) { | ||
| // Array, Set and Dictionary allow conversions, everything else | ||
| // requires their generic arguments to match exactly. | ||
| if (existingType->isKnownStdlibCollectionType()) |
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Maybe this check should also call hasConversions()?
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We allow injections into optional but not conversions of its generic arguments, this only covers situations like Int? conv $T and $T conv $U?.
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This spot is a lot narrower so I don't think we can use hasConversions here.
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We allow injections into optional but not conversions of its generic arguments,
The optional-to-optional conversion is a lot like Array upcast isn't it?
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Somewhat but it wasn’t allowed previously but the logic here so we are not changing the behavior.
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Expressions like:
func test<T>(_: T, _: () -> T?) {}
class A {
}
class B : A {}
test(A()) {
Optional(B())
}
Still work fine because optional conversion differ from collection upcast in that solver doesn't introduce a separate type variable when they are bound so even if we infer result type to be B? it would still much fine against A? from context, unlike what happens for collections where we'd infer the element and match it directly.
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Also allowing both Int? and $T? bindings results in the same solution multiple times, something that CSRanking doesn't properly handle today because we don't expect that to happen without score or binding differences, that's most likely the logic didn't have change check, I'd rather we revisit this whole method in the future than try to fix it now...
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@swift-ci please test source compatibility |
…collection types
This is follow-up to #76487
It's reasonable to coalesce bindings of different kind if they don't allow implicit conversions like stdlib collection types do.
Resolves: #77003