Diagnose missing 'template' keywords in more cases.

We track when we see a name-shaped expression followed by a '<' token
and parse the '<' as a comparison. Then:

 * if we see a token sequence that cannot possibly be an expression but
   can be a template argument (in particular, a type-id) that follows
   either a ',' or the '<', diagnose that the '<' was supposed to start
   a template argument list, and
 * if we see '>()', diagnose that the '<' was supposed to start a
   template argument list.

This only changes the diagnostic for error cases, and in practice
appears to catch the most common cases where a missing 'template'
keyword leads to parse errors within a template.

Differential Revision: https://reviews.llvm.org/D48571

llvm-svn: 335687

1 files changed, 8 insertions, 0 deletions

diff --git a/clang/lib/Parse/ParseCXXInlineMethods.cpp b/clang/lib/Parse/ParseCXXInlineMethods.cpp
index bccf4239c1b..77f2dccfede 100644
--- a/clang/lib/Parse/ParseCXXInlineMethods.cpp
+++ b/clang/lib/Parse/ParseCXXInlineMethods.cpp
@@ -312,6 +312,8 @@ void Parser::ParseLexedMethodDeclaration(LateParsedMethodDeclaration &LM) {
     Actions.ActOnDelayedCXXMethodParameter(getCurScope(), Param);
     std::unique_ptr<CachedTokens> Toks = std::move(LM.DefaultArgs[I].Toks);
     if (Toks) {
+      ParenBraceBracketBalancer BalancerRAIIObj(*this);
+
       // Mark the end of the default argument so that we know when to stop when
       // we parse it later on.
       Token LastDefaultArgToken = Toks->back();
@@ -384,6 +386,8 @@ void Parser::ParseLexedMethodDeclaration(LateParsedMethodDeclaration &LM) {
 
   // Parse a delayed exception-specification, if there is one.
   if (CachedTokens *Toks = LM.ExceptionSpecTokens) {
+    ParenBraceBracketBalancer BalancerRAIIObj(*this);
+
     // Add the 'stop' token.
     Token LastExceptionSpecToken = Toks->back();
     Token ExceptionSpecEnd;
@@ -489,6 +493,8 @@ void Parser::ParseLexedMethodDef(LexedMethod &LM) {
     ++CurTemplateDepthTracker;
   }
 
+  ParenBraceBracketBalancer BalancerRAIIObj(*this);
+
   assert(!LM.Toks.empty() && "Empty body!");
   Token LastBodyToken = LM.Toks.back();
   Token BodyEnd;
@@ -609,6 +615,8 @@ void Parser::ParseLexedMemberInitializer(LateParsedMemberInitializer &MI) {
   if (!MI.Field || MI.Field->isInvalidDecl())
     return;
 
+  ParenBraceBracketBalancer BalancerRAIIObj(*this);
+
   // Append the current token at the end of the new token stream so that it
   // doesn't get lost.
   MI.Toks.push_back(Tok);