Rename experimental feature to ParserASTGen

Author: DougGregor

include/swift/Basic/Features.def

@@ -141,8 +141,9 @@ EXPERIMENTAL_FEATURE(ParserSequenceFolding)
 /// Enables implicit some while also enabling existential `any`
 EXPERIMENTAL_FEATURE(ImplicitSome)
 
-/// Parse using the Swift (swift-syntax) parser and use ASTGen.
-EXPERIMENTAL_FEATURE(SwiftParser)
+/// Parse using the Swift (swift-syntax) parser and use ASTGen to generate the
+/// corresponding syntax tree.
+EXPERIMENTAL_FEATURE(ParserASTGen)
 
 #undef EXPERIMENTAL_FEATURE
 #undef UPCOMING_FEATURE

lib/AST/ASTPrinter.cpp

@@ -3091,7 +3091,7 @@ static bool usesFeatureAdditiveArithmeticDerivedConformances(Decl *decl) {
   return false;
 }
 
-static bool usesFeatureSwiftParser(Decl *decl) {
+static bool usesFeatureParserASTGen(Decl *decl) {
   return false;
 }
 

lib/Parse/ParseDecl.cpp

@@ -185,7 +185,7 @@ void Parser::parseTopLevel(SmallVectorImpl<Decl *> &decls) {
   StringRef contents =
       SourceMgr.extractText(SourceMgr.getRangeForBuffer(L->getBufferID()));
 
-  if (Context.LangOpts.hasFeature(Feature::SwiftParser)) {
+  if (Context.LangOpts.hasFeature(Feature::ParserASTGen)) {
     parseTopLevelSwift(contents.data(), CurDeclContext, &Context, &decls, appendToVector);
 
     for (auto decl : decls) {