[CSSimplify] When trying to simplify bind with error type fail gracefully
#16866
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…efully Since member lookup doesn't check requirements it might sometimes return types which are not visible in the current context e.g. typealias defined in constrained extension, substitution of which might produce error type for base, so assignement should thead lightly and just fail if it encounters such types. Resolves: rdar://problem/39931339 Resolves: SR-5013
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@rudkx I've talked to @DougGregor about this as well and we came to the conclusion that there is no obviously better way to handle situations like that at the moment. I'm working on the separate patch which is going to add typealias' requirements to constraint system to check them earlier which helps to diagnose some expressions better but not when types like that are involved in disjunctions e.g. protocol P {}
struct S<T> {}
extension S where T : P {
typealias A = Int
}
_ = S<Int>.A() // currently succeeds but should produce error saying that `Int` doesn't conform to `P`. |
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@swift-ci please test |
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@swift-ci please test source compatibility |
rudkx
approved these changes
May 29, 2018
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Since member lookup doesn't check requirements
it might sometimes return types which are not
visible in the current context e.g. typealias
defined in constrained extension, substitution
of which might produce error type for base, so
assignement should thead lightly and just fail
if it encounters such types.
Resolves: rdar://problem/39931339
Resolves SR-5013.