[modules] Enforce the rules that an explicit or partial specialization must be

declared before it is used. Because we don't use normal name lookup to find
these, the normal code to filter out non-visible names from name lookup results
does not apply.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@268585 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 28 insertions, 3 deletions

diff --git a/lib/Sema/SemaCXXScopeSpec.cpp b/lib/Sema/SemaCXXScopeSpec.cpp
index 2e774dd28c..ab0e709a97 100644
--- a/lib/Sema/SemaCXXScopeSpec.cpp
+++ b/lib/Sema/SemaCXXScopeSpec.cpp
@@ -117,8 +117,18 @@ DeclContext *Sema::computeDeclContext(const CXXScopeSpec &SS,
           // specializations, we're entering into the definition of that
           // class template partial specialization.
           if (ClassTemplatePartialSpecializationDecl *PartialSpec
-                = ClassTemplate->findPartialSpecialization(ContextType))
+                = ClassTemplate->findPartialSpecialization(ContextType)) {
+            // A declaration of the partial specialization must be visible.
+            // We can always recover here, because this only happens when we're
+            // entering the context, and that can't happen in a SFINAE context.
+            assert(!isSFINAEContext() &&
+                   "partial specialization scope specifier in SFINAE context?");
+            if (!hasVisibleDeclaration(PartialSpec))
+              diagnoseMissingImport(SS.getLastQualifierNameLoc(), PartialSpec,
+                                    MissingImportKind::PartialSpecialization,
+                                    /*Recover*/true);
             return PartialSpec;
+          }
         }
       } else if (const RecordType *RecordT = NNSType->getAs<RecordType>()) {
         // The nested name specifier refers to a member of a class template.
@@ -195,6 +205,8 @@ bool Sema::RequireCompleteDeclContext(CXXScopeSpec &SS,
   TagDecl *tag = dyn_cast<TagDecl>(DC);
 
   // If this is a dependent type, then we consider it complete.
+  // FIXME: This is wrong; we should require a (visible) definition to
+  // exist in this case too.
   if (!tag || tag->isDependentContext())
     return false;
 
@@ -218,10 +230,23 @@ bool Sema::RequireCompleteDeclContext(CXXScopeSpec &SS,
   // Fixed enum types are complete, but they aren't valid as scopes
   // until we see a definition, so awkwardly pull out this special
   // case.
-  // FIXME: The definition might not be visible; complain if it is not.
   const EnumType *enumType = dyn_cast_or_null<EnumType>(tagType);
-  if (!enumType || enumType->getDecl()->isCompleteDefinition())
+  if (!enumType)
     return false;
+  if (enumType->getDecl()->isCompleteDefinition()) {
+    // If we know about the definition but it is not visible, complain.
+    NamedDecl *SuggestedDef = nullptr;
+    if (!hasVisibleDefinition(enumType->getDecl(), &SuggestedDef,
+                              /*OnlyNeedComplete*/false)) {
+      // If the user is going to see an error here, recover by making the
+      // definition visible.
+      bool TreatAsComplete = !isSFINAEContext();
+      diagnoseMissingImport(loc, SuggestedDef, MissingImportKind::Definition,
+                            /*Recover*/TreatAsComplete);
+      return !TreatAsComplete;
+    }
+    return false;
+  }
 
   // Try to instantiate the definition, if this is a specialization of an
   // enumeration temploid.