Integrating libSyntax into the compiler pipelineの最初のPRがrevertされた後に気配を感じなくなったので、わいわいswiftc発表までに内容固まるか不安だ... https://github.com/apple/swift/pull/25193

[Parser] Decouple the parser from AST creation (part 1) by jansvob...

Instead of creating the AST directly in the parser (and libSyntax or SwiftSyntax via SyntaxParsingContext), make Parser to explicitly create a tree of ParsedSyntaxNodes. Their OpaqueSyntaxNodes can...