Improve recovery when we see a dependent template name that is missing

the required "template" keyword, using the same heuristics we do for
dependent template names in member access expressions, e.g.,

test/SemaTemplate/dependent-template-recover.cpp:11:8: error: use 'template'
      keyword to treat 'getAs' as a dependent template name
    T::getAs<U>();
       ^
       template 

Fixes PR5404.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@104409 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 25 insertions, 0 deletions

diff --git a/lib/Parse/ParseExprCXX.cpp b/lib/Parse/ParseExprCXX.cpp
index 1588b69bda..0a909f626f 100644
--- a/lib/Parse/ParseExprCXX.cpp
+++ b/lib/Parse/ParseExprCXX.cpp
@@ -307,6 +307,31 @@ bool Parser::ParseOptionalCXXScopeSpecifier(CXXScopeSpec &SS,
                                     SourceLocation(), false))
           return true;
         continue;
+      } 
+      
+      if (MemberOfUnknownSpecialization && (ObjectType || SS.isSet()) && 
+          IsTemplateArgumentList(1)) {
+        // We have something like t::getAs<T>, where getAs is a 
+        // member of an unknown specialization. However, this will only
+        // parse correctly as a template, so suggest the keyword 'template'
+        // before 'getAs' and treat this as a dependent template name.
+        Diag(Tok.getLocation(), diag::err_missing_dependent_template_keyword)
+          << II.getName()
+          << FixItHint::CreateInsertion(Tok.getLocation(), "template ");
+        
+        Template = Actions.ActOnDependentTemplateName(Tok.getLocation(), SS, 
+                                                      TemplateName, ObjectType,
+                                                      EnteringContext);
+        if (!Template.get())
+          return true;     
+        
+        // Consume the identifier.
+        ConsumeToken();
+        if (AnnotateTemplateIdToken(Template, TNK_Dependent_template_name, &SS,
+                                    TemplateName, SourceLocation(), false))
+          return true;
+        
+        continue;        
       }
     }