Improve support for out-of-line definitions of nested templates and
their members, including member class template, member function
templates, and member classes and functions of member templates.

To actually parse the nested-name-specifiers that qualify the name of
an out-of-line definition of a member template, e.g.,

  template<typename X> template<typename Y>
  X Outer<X>::Inner1<Y>::foo(Y) {
    return X();
  }

we need to look for the template names (e.g., "Inner1") as a member of
the current instantiation (Outer<X>), even before we have entered the
scope of the current instantiation. Since we can't do this in general
(i.e., we should not be looking into all dependent
nested-name-specifiers as if they were the current instantiation), we
rely on the parser to tell us when it is parsing a declaration
specifier sequence, and, therefore, when we should consider the
current scope specifier to be a current instantiation.

Printing of complicated, dependent nested-name-specifiers may be
somewhat broken by this commit; I'll add tests for this issue and fix
the problem (if it still exists) in a subsequent commit.

llvm-svn: 80044
diff --git a/clang/lib/Sema/Sema.h b/clang/lib/Sema/Sema.h
index 03e6417..9db3fae 100644
--- a/clang/lib/Sema/Sema.h
+++ b/clang/lib/Sema/Sema.h
@@ -1265,7 +1265,8 @@
                                 LookupNameKind NameKind, 
                                 bool RedeclarationOnly = false,
                                 bool AllowBuiltinCreation = false,
-                                SourceLocation Loc = SourceLocation());
+                                SourceLocation Loc = SourceLocation(),
+                                bool EnteringContext = false);
 
   ObjCProtocolDecl *LookupProtocol(IdentifierInfo *II);
   ObjCCategoryImplDecl *LookupObjCCategoryImpl(IdentifierInfo *II);
@@ -1951,7 +1952,8 @@
                                                   const CXXScopeSpec &SS,
                                                   SourceLocation IdLoc,
                                                   SourceLocation CCLoc,
-                                                  IdentifierInfo &II);
+                                                  IdentifierInfo &II,
+                                                  bool EnteringContext);
 
   /// ActOnCXXNestedNameSpecifier - Called during parsing of a
   /// nested-name-specifier that involves a template-id, e.g.,
@@ -2205,8 +2207,9 @@
   // C++ Templates [C++ 14]
   //
   virtual TemplateNameKind isTemplateName(const IdentifierInfo &II, Scope *S,
-                                          TemplateTy &Template,
-                                          const CXXScopeSpec *SS = 0);
+                                          const CXXScopeSpec *SS,
+                                          bool EnteringContext,
+                                          TemplateTy &Template);
   bool DiagnoseTemplateParameterShadow(SourceLocation Loc, Decl *PrevDecl);
   TemplateDecl *AdjustDeclIfTemplate(DeclPtrTy &Decl);