1 files changed, 6 insertions, 1 deletions
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index f9c1a014260..203adeab8d4 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -3780,10 +3780,15 @@ Decl *Sema::ParsedFreeStandingDeclSpec(Scope *S, AccessSpecifier AS,
   bool IsExplicitSpecialization =
     !TemplateParams.empty() && TemplateParams.back()->size() == 0;
   if (Tag && SS.isNotEmpty() && !Tag->isCompleteDefinition() &&
-      !IsExplicitInstantiation && !IsExplicitSpecialization) {
+      !IsExplicitInstantiation && !IsExplicitSpecialization &&
+      !isa<ClassTemplatePartialSpecializationDecl>(Tag)) {
     // Per C++ [dcl.type.elab]p1, a class declaration cannot have a
     // nested-name-specifier unless it is an explicit instantiation
     // or an explicit specialization.
+    //
+    // FIXME: We allow class template partial specializations here too, per the
+    // obvious intent of DR1819.
+    //
     // Per C++ [dcl.enum]p1, an opaque-enum-declaration can't either.
     Diag(SS.getBeginLoc(), diag::err_standalone_class_nested_name_specifier)
         << GetDiagnosticTypeSpecifierID(DS.getTypeSpecType()) << SS.getRange();