Detect when the string "<::" is found in code after a cast or template name and is interpreted as "[:" because of the digraph "<:". When found, give an error with a fix-it to add whitespace between the "<" and "::".
Patch by Richard Trieu! Plus a small tweak from me to deal with one of the tokens coming from a macro.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@129540 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Parse/ParseExprCXX.cpp b/lib/Parse/ParseExprCXX.cpp
index 385185e..c8f6741 100644
--- a/lib/Parse/ParseExprCXX.cpp
+++ b/lib/Parse/ParseExprCXX.cpp
@@ -20,6 +20,55 @@
using namespace clang;
+static int SelectDigraphErrorMessage(tok::TokenKind Kind) {
+ switch (Kind) {
+ case tok::kw_template: return 0;
+ case tok::kw_const_cast: return 1;
+ case tok::kw_dynamic_cast: return 2;
+ case tok::kw_reinterpret_cast: return 3;
+ case tok::kw_static_cast: return 4;
+ default:
+ assert(0 && "Unknown type for digraph error message.");
+ return -1;
+ }
+}
+
+// Are the two tokens adjacent in the same source file?
+static bool AreTokensAdjacent(Preprocessor &PP, Token &First, Token &Second) {
+ SourceManager &SM = PP.getSourceManager();
+ SourceLocation FirstLoc = SM.getSpellingLoc(First.getLocation());
+ SourceLocation FirstEnd = FirstLoc.getFileLocWithOffset(First.getLength());
+ return FirstEnd == SM.getSpellingLoc(Second.getLocation());
+}
+
+// Suggest fixit for "<::" after a cast.
+static void FixDigraph(Parser &P, Preprocessor &PP, Token &DigraphToken,
+ Token &ColonToken, tok::TokenKind Kind, bool AtDigraph) {
+ // Pull '<:' and ':' off token stream.
+ if (!AtDigraph)
+ PP.Lex(DigraphToken);
+ PP.Lex(ColonToken);
+
+ SourceRange Range;
+ Range.setBegin(DigraphToken.getLocation());
+ Range.setEnd(ColonToken.getLocation());
+ P.Diag(DigraphToken.getLocation(), diag::err_missing_whitespace_digraph)
+ << SelectDigraphErrorMessage(Kind)
+ << FixItHint::CreateReplacement(Range, "< ::");
+
+ // Update token information to reflect their change in token type.
+ ColonToken.setKind(tok::coloncolon);
+ ColonToken.setLocation(ColonToken.getLocation().getFileLocWithOffset(-1));
+ ColonToken.setLength(2);
+ DigraphToken.setKind(tok::less);
+ DigraphToken.setLength(1);
+
+ // Push new tokens back to token stream.
+ PP.EnterToken(ColonToken);
+ if (!AtDigraph)
+ PP.EnterToken(DigraphToken);
+}
+
/// \brief Parse global scope or nested-name-specifier if present.
///
/// Parses a C++ global scope specifier ('::') or nested-name-specifier (which
@@ -287,6 +336,29 @@
continue;
}
+ // Check for '<::' which should be '< ::' instead of '[:' when following
+ // a template name.
+ if (Next.is(tok::l_square) && Next.getLength() == 2) {
+ Token SecondToken = GetLookAheadToken(2);
+ if (SecondToken.is(tok::colon) &&
+ AreTokensAdjacent(PP, Next, SecondToken)) {
+ TemplateTy Template;
+ UnqualifiedId TemplateName;
+ TemplateName.setIdentifier(&II, Tok.getLocation());
+ bool MemberOfUnknownSpecialization;
+ if (Actions.isTemplateName(getCurScope(), SS,
+ /*hasTemplateKeyword=*/false,
+ TemplateName,
+ ObjectType,
+ EnteringContext,
+ Template,
+ MemberOfUnknownSpecialization)) {
+ FixDigraph(*this, PP, Next, SecondToken, tok::kw_template,
+ /*AtDigraph*/false);
+ }
+ }
+ }
+
// nested-name-specifier:
// type-name '<'
if (Next.is(tok::less)) {
@@ -453,6 +525,13 @@
SourceLocation OpLoc = ConsumeToken();
SourceLocation LAngleBracketLoc = Tok.getLocation();
+ // Check for "<::" which is parsed as "[:". If found, fix token stream,
+ // diagnose error, suggest fix, and recover parsing.
+ Token Next = NextToken();
+ if (Tok.is(tok::l_square) && Tok.getLength() == 2 && Next.is(tok::colon) &&
+ AreTokensAdjacent(PP, Tok, Next))
+ FixDigraph(*this, PP, Tok, Next, Kind, /*AtDigraph*/true);
+
if (ExpectAndConsume(tok::less, diag::err_expected_less_after, CastName))
return ExprError();