[MSVC] Explicit specializations can be declared in any namespace (fix for http://llvm.org/PR13738)

MS compiler emits no errors in case of explicit specializations outside declaration enclosing namespaces, even when language extensions are disabled.
The patch is to suppress errors and emit extension warnings if explicit specializations are not declared in the corresponding namespaces.
This fixes PR13738.

Patch by Alexey Frolov.

Differential Revision: http://reviews.llvm.org/D8283

llvm-svn: 232800

1 files changed, 7 insertions, 5 deletions

diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index 6cba79a5fbb..fad15bbc4f6 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -5835,11 +5835,13 @@ static bool CheckTemplateSpecializationScope(Sema &S,
     if (isa<TranslationUnitDecl>(SpecializedContext))
       S.Diag(Loc, diag::err_template_spec_redecl_global_scope)
         << EntityKind << Specialized;
-    else if (isa<NamespaceDecl>(SpecializedContext))
-      S.Diag(Loc, diag::err_template_spec_redecl_out_of_scope)
-        << EntityKind << Specialized
-        << cast<NamedDecl>(SpecializedContext);
-    else
+    else if (isa<NamespaceDecl>(SpecializedContext)) {
+      int Diag = diag::err_template_spec_redecl_out_of_scope;
+      if (S.getLangOpts().MicrosoftExt)
+        Diag = diag::ext_ms_template_spec_redecl_out_of_scope;
+      S.Diag(Loc, Diag) << EntityKind << Specialized
+                        << cast<NamedDecl>(SpecializedContext);
+    } else
       llvm_unreachable("unexpected namespace context for specialization");
 
     S.Diag(Specialized->getLocation(), diag::note_specialized_entity);