[Variadic Generics] type parameter pack syntax change: T... -> each T #1384
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@swift-ci please test |
| let each = self.consume(if: .keyword(.each)) | ||
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| let (unexpectedBetweenEachAndName, name) = self.expectIdentifier() | ||
| if attributes == nil && unexpectedBetweenEachAndName == nil && name.isMissing && elements.isEmpty { |
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You need to check that each is nil here as well, otherwise we could drop each and not round-trip. A test case that currently fails should be if you open a generic argument list, write each and then reach the end of the file, i.e.
func foo<eachThere was a problem hiding this comment.
each is supposed to be optional/nullable because the absence of each indicates a standard generic type parameter and the presence of each indicates a variadic type parameter pack. This was the case before my PR as well except prior to my syntax change, it was postfix ellipsis that made the distinction rather than the preceding each. Admittedly I do not know what is meant by "we could drop each and not round-trip"?
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swift-syntax preserves each token in the source file in the parse tree as it was written, even if you hav something invalid like each not followed by a type parameter.
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