When explicitly specializing a member that is a template, mark the

template as a specialization. For example, this occurs with:

  template<typename T>
  struct X {
    template<typename U> struct Inner { /* ... */ };
  };

  template<> template<typename T>
  struct X<int>::Inner {
    T member;
  };

We need to treat templates that are member specializations as special
in two contexts:

  - When looking for a definition of a member template, we look
    through the instantiation chain until we hit the primary template
    *or a member specialization*. This allows us to distinguish
    between the primary "Inner" definition and the X<int>::Inner
    definition, above.
  - When computing all of the levels of template arguments needed to
    instantiate a member template, don't add template arguments
    from contexts outside of the instantiation of a member
    specialization, since the user has already manually substituted
    those arguments.

Fix up the existing test for p18, which was actually wrong (but we
didn't diagnose it because of our poor handling of member
specializations of templates), and add a new test for member
specializations of templates.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@83974 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 20 insertions, 4 deletions

diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 69426ee755..a1582a900f 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -1735,6 +1735,10 @@ Sema::HandleDeclarator(Scope *S, Declarator &D,
       return DeclPtrTy();
     }
 
+    if (!DC->isDependentContext() && 
+        RequireCompleteDeclContext(D.getCXXScopeSpec()))
+      return DeclPtrTy();
+    
     LookupResult Res;
     LookupQualifiedName(Res, DC, Name, LookupOrdinaryName, true);
     PrevDecl = Res.getAsSingleDecl(Context);
@@ -2807,11 +2811,11 @@ Sema::ActOnFunctionDeclarator(Scope* S, Declarator& D, DeclContext* DC,
   } else if (isExplicitSpecialization && isa<CXXMethodDecl>(NewFD) &&
              CheckMemberSpecialization(NewFD, PrevDecl))
     NewFD->setInvalidDecl();
-           
+    
   // Perform semantic checking on the function declaration.
   bool OverloadableAttrRequired = false; // FIXME: HACK!
-  CheckFunctionDeclaration(NewFD, PrevDecl, Redeclaration,
-                           /*FIXME:*/OverloadableAttrRequired);
+  CheckFunctionDeclaration(NewFD, PrevDecl, isExplicitSpecialization,
+                           Redeclaration, /*FIXME:*/OverloadableAttrRequired);
 
   if (D.getCXXScopeSpec().isSet() && !NewFD->isInvalidDecl()) {
     // An out-of-line member function declaration must also be a
@@ -2914,8 +2918,12 @@ Sema::ActOnFunctionDeclarator(Scope* S, Declarator& D, DeclContext* DC,
 /// that have been instantiated via C++ template instantiation (called
 /// via InstantiateDecl).
 ///
+/// \param IsExplicitSpecialiation whether this new function declaration is
+/// an explicit specialization of the previous declaration.
+///
 /// This sets NewFD->isInvalidDecl() to true if there was an error.
 void Sema::CheckFunctionDeclaration(FunctionDecl *NewFD, NamedDecl *&PrevDecl,
+                                    bool IsExplicitSpecialization,
                                     bool &Redeclaration,
                                     bool &OverloadableAttrRequired) {
   // If NewFD is already known erroneous, don't do any of this checking.
@@ -2990,7 +2998,7 @@ void Sema::CheckFunctionDeclaration(FunctionDecl *NewFD, NamedDecl *&PrevDecl,
 
       if (FunctionTemplateDecl *OldTemplateDecl
                                     = dyn_cast<FunctionTemplateDecl>(OldDecl)) {
-        NewFD->setPreviousDeclaration(OldTemplateDecl->getTemplatedDecl());
+        NewFD->setPreviousDeclaration(OldTemplateDecl->getTemplatedDecl());        
         FunctionTemplateDecl *NewTemplateDecl
           = NewFD->getDescribedFunctionTemplate();
         assert(NewTemplateDecl && "Template/non-template mismatch");
@@ -2999,6 +3007,14 @@ void Sema::CheckFunctionDeclaration(FunctionDecl *NewFD, NamedDecl *&PrevDecl,
           Method->setAccess(OldTemplateDecl->getAccess());
           NewTemplateDecl->setAccess(OldTemplateDecl->getAccess());
         }
+        
+        // If this is an explicit specialization of a member that is a function
+        // template, mark it as a member specialization.
+        if (IsExplicitSpecialization && 
+            NewTemplateDecl->getInstantiatedFromMemberTemplate()) {
+          NewTemplateDecl->setMemberSpecialization();
+          assert(OldTemplateDecl->isMemberSpecialization());
+        }
       } else {
         if (isa<CXXMethodDecl>(NewFD)) // Set access for out-of-line definitions
           NewFD->setAccess(OldDecl->getAccess());