[cxx-interop] Support class template specializations in namespaces.

This just changes an assertion and adds a test.

Author: zoecarver

lib/ClangImporter/ImportDecl.cpp

@@ -3326,6 +3326,14 @@ namespace {
           continue;
         }
 
+        if (auto recordDecl = dyn_cast<clang::RecordDecl>(m)) {
+          // An injected class name decl will just point back to the parent
+          // decl, so don't import it.
+          if (recordDecl->isInjectedClassName()) {
+            continue;
+          }
+        }
+
         auto nd = dyn_cast<clang::NamedDecl>(m);
         if (!nd) {
           // We couldn't import the member, so we can't reference it in Swift.
@@ -3569,6 +3577,19 @@ namespace {
       return VisitCXXRecordDecl(def);
     }
 
+    Decl *VisitClassTemplateDecl(const clang::ClassTemplateDecl *decl) {
+      // When loading a namespace's sub-decls, we won't add template
+      // specilizations, so make sure to do that here.
+      for (auto spec : decl->specializations()) {
+        if (auto importedSpec = Impl.importDecl(spec, getVersion())) {
+          if (auto namespaceDecl =
+                  dyn_cast<EnumDecl>(importedSpec->getDeclContext()))
+            namespaceDecl->addMember(importedSpec);
+        }
+      }
+      return nullptr;
+    }
+
     Decl *VisitClassTemplatePartialSpecializationDecl(
         const clang::ClassTemplatePartialSpecializationDecl *decl) {
       // Note: partial template specializations are not imported.

test/Interop/Cxx/templates/Inputs/class-template-in-namespace.h

@@ -0,0 +1,8 @@
+namespace Space {
+
+template <class...> struct Ship;
+template <class T, class... Args> struct Ship<T(Args...)> {};
+
+using Orbiter = Ship<void(bool)>;
+
+} // namespace Space

test/Interop/Cxx/templates/Inputs/module.modulemap

@@ -57,3 +57,7 @@ module ClassTemplateTemplateParameter {
 module ClassTemplateWithTypedef {
   header "class-template-with-typedef.h"
 }
+
+module ClassTemplateInNamespace {
+  header "class-template-in-namespace.h"
+}

test/Interop/Cxx/templates/class-template-in-namespace-module-interface.swift

@@ -0,0 +1,8 @@
+// RUN: %target-swift-ide-test -print-module -module-to-print=ClassTemplateInNamespace -I %S/Inputs -source-filename=x -enable-cxx-interop | %FileCheck %s
+
+// CHECK: enum Space {
+// CHECK:   struct __CxxTemplateInstN5Space4ShipIJFvbEEEE {
+// CHECK:     init()
+// CHECK:   }
+// CHECK:   typealias Orbiter = Space.__CxxTemplateInstN5Space4ShipIJFvbEEEE
+// CHECK: }