Building SwiftSyntax and missing _InternalSwiftSyntaxParser

[SDGGiesbrecht (Jeremy David Giesbrecht)]

You can find more info on rigging it for macOS in the following thread, but iOS may involve additional hurdles (if it works at all...)

SwiftSyntax with Swift 5.1

Is a semantic version of the SwiftSyntax package for Swift 5.1 coming soon? @akyrtzi While I wait, I have been toying with a fork in an attempt to get a head start on updating client code, but I have been running into trouble. I couldn’t find a swift-5.1-RELEASE tag, so I checked out swift-5.1-branch. Then I de‐GYB‐ified the package. In that state, it builds fine, and the tests pass in the package manager or with the result of generate-xcodeproj. However, if I open the package directly in Xcode…