Parser: disable lexer diagnostics during delayed parsing.

The lexer diagnostics have already been emitted during token skipping.

Author: nkcsgexi

include/swift/Parse/Parser.h

@@ -346,6 +346,9 @@ class Parser {
   SyntaxParsingContext *SyntaxContext;
 
 public:
+  Parser(unsigned BufferID, SourceFile &SF, DiagnosticEngine* LexerDiags,
+         SILParserTUStateBase *SIL,
+         PersistentParserState *PersistentState);
   Parser(unsigned BufferID, SourceFile &SF, SILParserTUStateBase *SIL,
          PersistentParserState *PersistentState = nullptr);
   Parser(std::unique_ptr<Lexer> Lex, SourceFile &SF,

lib/Parse/ParseDecl.cpp

@@ -192,7 +192,10 @@ void PersistentParserState::parseMembers(IterableDeclContext *IDC) {
   // the PersistentParserState will be used to continuously parse the rest of
   // the file linearly.
   llvm::SaveAndRestore<ParserPosition> Pos(MarkedPos, ParserPosition());
-  Parser TheParser(BufferID, SF, nullptr, this);
+
+  // Lexer diaganostics have been emitted during skipping, so we disable lexer's
+  // diagnostic engine here.
+  Parser TheParser(BufferID, SF, /*No Lexer Diags*/nullptr, nullptr, this);
   // Disable libSyntax creation in the delayed parsing.
   TheParser.SyntaxContext->disable();
   TheParser.parseDeclListDelayed(IDC);
@@ -2292,7 +2295,8 @@ static unsigned skipUntilMatchingRBrace(Parser &P, bool &HasPoundDirective,
   SyntaxParsingContext BodyContext(SyntaxContext, SyntaxKind::TokenList);
   unsigned OpenBraces = 1;
   while (OpenBraces != 0 && P.Tok.isNot(tok::eof)) {
-    HasPoundDirective |= P.Tok.isAny(tok::pound_sourceLocation, tok::pound_line);
+    HasPoundDirective |= P.Tok.isAny(tok::pound_sourceLocation, tok::pound_line,
+      tok::pound_if, tok::pound_else, tok::pound_endif, tok::pound_elseif);
     if (P.consumeIf(tok::l_brace)) {
       OpenBraces++;
       continue;

lib/Parse/Parser.cpp

@@ -331,12 +331,18 @@ swift::tokenizeWithTrivia(const LangOptions &LangOpts, const SourceManager &SM,
 // Setup and Helper Methods
 //===----------------------------------------------------------------------===//
 
+
 Parser::Parser(unsigned BufferID, SourceFile &SF, SILParserTUStateBase *SIL,
                PersistentParserState *PersistentState)
+    : Parser(BufferID, SF, &SF.getASTContext().Diags, SIL, PersistentState) {}
+
+Parser::Parser(unsigned BufferID, SourceFile &SF, DiagnosticEngine* LexerDiags,
+               SILParserTUStateBase *SIL,
+               PersistentParserState *PersistentState)
     : Parser(
           std::unique_ptr<Lexer>(new Lexer(
               SF.getASTContext().LangOpts, SF.getASTContext().SourceMgr,
-              BufferID, &SF.getASTContext().Diags,
+              BufferID, LexerDiags,
               /*InSILMode=*/SIL != nullptr,
               SF.Kind == SourceFileKind::Main
                   ? HashbangMode::Allowed