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, 2 insertions, 0 deletions

diff --git a/clang/lib/Parse/ParseStmt.cpp b/clang/lib/Parse/ParseStmt.cpp
index 44406002c0d..8c4a3056ec0 100644
--- a/clang/lib/Parse/ParseStmt.cpp
+++ b/clang/lib/Parse/ParseStmt.cpp
@@ -1621,6 +1621,8 @@ StmtResult Parser::ParseForStatement(SourceLocation *TrailingElseLoc) {
                                                    attrs, attrs.Range.getEnd());
     ForRange = true;
   } else if (isForInitDeclaration()) {  // for (int X = 4;
+    ParenBraceBracketBalancer BalancerRAIIObj(*this);
+
     // Parse declaration, which eats the ';'.
     if (!C99orCXXorObjC)   // Use of C99-style for loops in C90 mode?
       Diag(Tok, diag::ext_c99_variable_decl_in_for_loop);