3 files changed, 45 insertions, 2 deletions

diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index eebb11da99..1143b305ad 100644
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -260,6 +260,25 @@ ASTContext::setInstantiatedFromUnresolvedUsingDecl(UsingDecl *UD,
   InstantiatedFromUnresolvedUsingDecl[UD] = UUD;
 }
 
+FieldDecl *ASTContext::getInstantiatedFromUnnamedFieldDecl(FieldDecl *Field) {
+  llvm::DenseMap<FieldDecl *, FieldDecl *>::iterator Pos
+    = InstantiatedFromUnnamedFieldDecl.find(Field);
+  if (Pos == InstantiatedFromUnnamedFieldDecl.end())
+    return 0;
+  
+  return Pos->second;
+}
+
+void ASTContext::setInstantiatedFromUnnamedFieldDecl(FieldDecl *Inst,
+                                                     FieldDecl *Tmpl) {
+  assert(!Inst->getDeclName() && "Instantiated field decl is not unnamed");
+  assert(!Tmpl->getDeclName() && "Template field decl is not unnamed");
+  assert(!InstantiatedFromUnnamedFieldDecl[Inst] &&
+         "Already noted what unnamed field was instantiated from");
+  
+  InstantiatedFromUnnamedFieldDecl[Inst] = Tmpl;
+}
+
 namespace {
   class BeforeInTranslationUnit 
     : std::binary_function<SourceRange, SourceRange, bool> {
diff --git a/lib/Sema/SemaTemplateInstantiateDecl.cpp b/lib/Sema/SemaTemplateInstantiateDecl.cpp
index c5b2894c49..84e464aba3 100644
--- a/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -245,6 +245,11 @@ Decl *TemplateDeclInstantiator::VisitFieldDecl(FieldDecl *D) {
     if (Invalid)
       Field->setInvalidDecl();
     
+    if (!Field->getDeclName()) {
+      // Keep track of where this decl came from.
+      SemaRef.Context.setInstantiatedFromUnnamedFieldDecl(Field, D);
+    }
+    
     Owner->addDecl(Field);
   }
 
@@ -441,6 +446,8 @@ Decl *TemplateDeclInstantiator::VisitCXXRecordDecl(CXXRecordDecl *D) {
   if (Decl::FriendObjectKind FOK = D->getFriendObjectKind())
     Record->setObjectOfFriendDecl(FOK == Decl::FOK_Declared);
 
+  Record->setAnonymousStructOrUnion(D->isAnonymousStructOrUnion());
+
   Owner->addDecl(Record);
   return Record;
 }
@@ -1274,8 +1281,14 @@ static bool isInstantiationOf(ASTContext &Ctx, NamedDecl *D, Decl *Other) {
   if (ClassTemplateDecl *Temp = dyn_cast<ClassTemplateDecl>(Other))
     return isInstantiationOf(cast<ClassTemplateDecl>(D), Temp);
 
-  // FIXME: How can we find instantiations of anonymous unions?
-
+  if (FieldDecl *Field = dyn_cast<FieldDecl>(Other)) {
+    if (!Field->getDeclName()) {
+      // This is an unnamed field.
+      return Ctx.getInstantiatedFromUnnamedFieldDecl(Field) == 
+        cast<FieldDecl>(D);
+    }
+  }
+  
   return D->getDeclName() && isa<NamedDecl>(Other) &&
     D->getDeclName() == cast<NamedDecl>(Other)->getDeclName();
 }
diff --git a/lib/Sema/TreeTransform.h b/lib/Sema/TreeTransform.h
index 386a2c6d80..f1888c87a4 100644
--- a/lib/Sema/TreeTransform.h
+++ b/lib/Sema/TreeTransform.h
@@ -840,6 +840,17 @@ public:
                                      SourceRange QualifierRange,
                                      SourceLocation MemberLoc,
                                      NamedDecl *Member) {
+    if (!Member->getDeclName()) {
+      // We have a reference to an unnamed field.
+      assert(!Qualifier && "Can't have an unnamed field with a qualifier!");
+      
+      MemberExpr *ME = 
+        new (getSema().Context) MemberExpr(Base.takeAs<Expr>(), isArrow,
+                                           Member, MemberLoc,
+                                           cast<FieldDecl>(Member)->getType());
+      return getSema().Owned(ME);
+    }
+      
     CXXScopeSpec SS;
     if (Qualifier) {
       SS.setRange(QualifierRange);