Implement parsing of nested-name-specifiers that involve template-ids, e.g.,

  std::vector<int>::allocator_type

When we parse a template-id that names a type, it will become either a
template-id annotation (which is a parsed representation of a
template-id that has not yet been through semantic analysis) or a
typename annotation (where semantic analysis has resolved the
template-id to an actual type), depending on the context. We only
produce a type in contexts where we know that we only need type
information, e.g., in a type specifier. Otherwise, we create a
template-id annotation that can later be "upgraded" by transforming it
into a typename annotation when the parser needs a type. This occurs,
for example, when we've parsed "std::vector<int>" above and then see
the '::' after it. However, it means that when writing something like
this:

  template<> class Outer::Inner<int> { ... };

We have two tokens to represent Outer::Inner<int>: one token for the
nested name specifier Outer::, and one template-id annotation token
for Inner<int>, which will be passed to semantic analysis to define
the class template specialization.

Most of the churn in the template tests in this patch come from an
improvement in our error recovery from ill-formed template-ids.

llvm-svn: 65467

1 files changed, 14 insertions, 0 deletions

diff --git a/clang/lib/Sema/Sema.h b/clang/lib/Sema/Sema.h
index 7ee6e22bca1..fed2bbdf7c4 100644
--- a/clang/lib/Sema/Sema.h
+++ b/clang/lib/Sema/Sema.h
@@ -1338,6 +1338,20 @@ public:
                                                   SourceLocation CCLoc,
                                                   IdentifierInfo &II);
 
+  /// ActOnCXXNestedNameSpecifier - Called during parsing of a
+  /// nested-name-specifier that involves a template-id, e.g.,
+  /// "foo::bar<int, float>::", and now we need to build a scope
+  /// specifier. \p SS is empty or the previously parsed nested-name
+  /// part ("foo::"), \p Type is the already-parsed class template
+  /// specialization (or other template-id that names a type), \p
+  /// TypeRange is the source range where the type is located, and \p
+  /// CCLoc is the location of the trailing '::'.
+  virtual CXXScopeTy *ActOnCXXNestedNameSpecifier(Scope *S,
+                                                  const CXXScopeSpec &SS,
+                                                  TypeTy *Type,
+                                                  SourceRange TypeRange,
+                                                  SourceLocation CCLoc);
+
   /// ActOnCXXEnterDeclaratorScope - Called when a C++ scope specifier (global
   /// scope or nested-name-specifier) is parsed, part of a declarator-id.
   /// After this method is called, according to [C++ 3.4.3p3], names should be