Merge pull request swiftlang#35778 from ahoppen/minor-libsyntax-improvements

[libSyntax] Minor improvements

Author: ahoppen

include/swift/Parse/ParsedRawSyntaxRecorder.h

@@ -37,7 +37,7 @@ namespace syntax {
   enum class SyntaxKind;
 }
 
-class ParsedRawSyntaxRecorder {
+class ParsedRawSyntaxRecorder final {
   std::shared_ptr<SyntaxParseActions> SPActions;
 
 public:

include/swift/Parse/ParsedSyntax.h

@@ -22,7 +22,7 @@ class ParsedSyntax {
   ParsedRawSyntaxNode RawNode;
 
 public:
-  explicit ParsedSyntax(ParsedRawSyntaxNode rawNode)
+  explicit ParsedSyntax(ParsedRawSyntaxNode &&rawNode)
     : RawNode(std::move(rawNode)) {}
 
   const ParsedRawSyntaxNode &getRaw() const { return RawNode; }
@@ -38,19 +38,9 @@ class ParsedSyntax {
   /// Cast this Syntax node to a more specific type, asserting it's of the
   /// right kind.
   template <typename T>
-  T castTo() const {
+  T castTo() && {
     assert(is<T>() && "castTo<T>() node of incompatible type!");
-    return T { RawNode.copyDeferred() };
-  }
-
-  /// If this Syntax node is of the right kind, cast and return it,
-  /// otherwise return None.
-  template <typename T>
-  llvm::Optional<T> getAs() const {
-    if (is<T>()) {
-      return castTo<T>();
-    }
-    return llvm::None;
+    return T(std::move(RawNode));
   }
 
   ParsedSyntax copyDeferred() const {
@@ -69,7 +59,7 @@ class ParsedSyntax {
 
 class ParsedTokenSyntax final : public ParsedSyntax {
 public:
-  explicit ParsedTokenSyntax(ParsedRawSyntaxNode rawNode)
+  explicit ParsedTokenSyntax(ParsedRawSyntaxNode &&rawNode)
     : ParsedSyntax(std::move(rawNode)) {}
 
   tok getTokenKind() const {

lib/Parse/ParseType.cpp

@@ -400,11 +400,12 @@ ParserResult<TypeRepr> Parser::parseType(Diag<> MessageID,
         Builder.useAsyncKeyword(SyntaxContext->popToken());
 
       auto InputNode(std::move(*SyntaxContext->popIf<ParsedTypeSyntax>()));
-      if (auto TupleTypeNode = InputNode.getAs<ParsedTupleTypeSyntax>()) {
+      if (InputNode.is<ParsedTupleTypeSyntax>()) {
+        auto TupleTypeNode = std::move(InputNode).castTo<ParsedTupleTypeSyntax>();
         // Decompose TupleTypeSyntax and repack into FunctionType.
-        auto LeftParen = TupleTypeNode->getDeferredLeftParen();
-        auto Arguments = TupleTypeNode->getDeferredElements();
-        auto RightParen = TupleTypeNode->getDeferredRightParen();
+        auto LeftParen = TupleTypeNode.getDeferredLeftParen();
+        auto Arguments = TupleTypeNode.getDeferredElements();
+        auto RightParen = TupleTypeNode.getDeferredRightParen();
         Builder
           .useLeftParen(std::move(LeftParen))
           .useArguments(std::move(Arguments))

lib/SyntaxParse/RawSyntaxTokenCache.h

@@ -44,7 +44,7 @@ class RawSyntaxCacheNode : public llvm::FoldingSetNode {
       : Obj(Obj), IDRef(IDRef) {}
 
   /// Retrieve assciated RawSyntax.
-  RC<syntax::RawSyntax> get() { return Obj; }
+  const RC<syntax::RawSyntax> &get() { return Obj; }
 
   // Only allow allocation of Node using the allocator in SyntaxArena.
   void *operator new(size_t Bytes, RC<syntax::SyntaxArena> &Arena,