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d9095b1079
When checking whether a particular protocol conformance satisfies all of the protocol's requirements, we were suppressing substitution failures. In some cases, this would mean that we marked a conformance "invalid" without ever emitting a diagnostic, which would lead to downstream crashes. Instead, treat substitution failures somewhat more lazily. If we encounter one while performing the checking, put the conformance into a "delayed" list rather than failing immediately. Teach the top-level type checking loop to re-check these conformances, emitting a diagnostic if they fail the second time around. Fixes rdar://problem/35082483 and likely other issues that slipped through the type checker or blew up in unpredictable ways.
21 lines
358 B
Swift
21 lines
358 B
Swift
// RUN: not %target-swift-frontend %s -typecheck
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struct S : Sequence {
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struct Iterator : IteratorProtocol {
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mutating func next() -> Int? {
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fatalError()
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}
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}
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func makeIterator() -> Iterator {
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fatalError()
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}
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}
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extension S : Collection {
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typealias Index = Int
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var startIndex: Int { return 0 }
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var endIndex: Int { return 1 }
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}
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