Improve parser recovery when we encounter a dependent template name
that is missing the 'template' keyword, e.g.,
t->getAs<T>()
where getAs is a member of an unknown specialization. C++ requires
that we treat "getAs" as a value, but that would fail to parse since T
is the name of a type. We would then fail at the '>', since a type
cannot be followed by a '>'.
This is a very common error for C++ programmers to make, especially
since GCC occasionally allows it when it shouldn't (as does Visual
C++). So, when we are in this case, we use tentative parsing to see if
the tokens starting at "<" can only be parsed as a template argument
list. If so, we produce a diagnostic with a fix-it that states that
the 'template' keyword is needed:
test/SemaTemplate/dependent-template-recover.cpp:5:8: error: 'template' keyword
is required to treat 'getAs' as a dependent template name
t->getAs<T>();
^
template
This is just a start of this patch; I'd like to apply the same
approach to everywhere that a template-id with dependent template name
can be parsed.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@104406 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/Sema.h b/lib/Sema/Sema.h
index 0870431..1b61800 100644
--- a/lib/Sema/Sema.h
+++ b/lib/Sema/Sema.h
@@ -2800,14 +2800,16 @@
// C++ Templates [C++ 14]
//
void LookupTemplateName(LookupResult &R, Scope *S, CXXScopeSpec &SS,
- QualType ObjectType, bool EnteringContext);
+ QualType ObjectType, bool EnteringContext,
+ bool &MemberOfUnknownSpecialization);
virtual TemplateNameKind isTemplateName(Scope *S,
CXXScopeSpec &SS,
UnqualifiedId &Name,
TypeTy *ObjectType,
bool EnteringContext,
- TemplateTy &Template);
+ TemplateTy &Template,
+ bool &MemberOfUnknownSpecialization);
virtual bool DiagnoseUnknownTemplateName(const IdentifierInfo &II,
SourceLocation IILoc,