Everything compiles.

base/not_null.hpp

@@ -342,6 +342,9 @@ template<typename Pointer>
 not_null<Pointer> check_not_null(not_null<Pointer> pointer);
 #endif
 
+template<typename T, typename... Args>
+not_null<std::shared_ptr<T>> make_not_null_shared(Args&&... args);
+
 // Factory for a |not_null<std::unique_ptr<T>>|, forwards the arguments to the
 // constructor of T.  |make_not_null_unique<T>(args)| is interchangeable with
 // |check_not_null(make_unique<T>(args))|, but does not perform a |CHECK|, since
@@ -364,10 +367,9 @@ not_null<Result> dynamic_cast_not_null(not_null<std::unique_ptr<T>>&& pointer);
 
 using internal::check_not_null;
 using internal::dynamic_cast_not_null;
+using internal::make_not_null_shared;
 using internal::make_not_null_unique;
 using internal::not_null;
-using internal::NotNullStorage;
-using internal::operator<<;
 using internal::remove_not_null;
 
 }  // namespace _not_null

base/status_utilities.hpp

@@ -26,7 +26,7 @@ absl::Status const& GetStatus(absl::StatusOr<T> const& s) {
   do {                                                                       \
     /* Using _status below to avoid capture problems if expr is "status". */ \
     ::absl::Status const _status =                                           \
-        (::principia::base::internal_status_utilities::GetStatus(expr));     \
+        (::principia::base::_status_utilities::internal::GetStatus(expr));   \
     if (!_status.ok())                                                       \
       return _status;                                                        \
   } while (false)

base/version.hpp

@@ -16,6 +16,8 @@ extern char const Version[];
 
 }  // namespace internal
 
+using internal::BuildDate;
+using internal::Version;
 
 }  // namespace _version
 }  // namespace base

generate_version_translation_unit.ps1

@@ -12,11 +12,15 @@ $versionheadertext = [string]::format(
     "`n"                                                                   +
     "namespace principia {{`n"                                             +
     "namespace base {{`n"                                                  +
+    "namespace _version {{`n"                                              +
+    "namespace internal {{`n"                                              +
     "`n"                                                                   +
-    "char const BuildDate[] = `"{0:yyyy'-'MM'-'dd'T'HH':'mm':'ssK}`";`n"  +
+    "char const BuildDate[] = `"{0:yyyy'-'MM'-'dd'T'HH':'mm':'ssK}`";`n"   +
     "char const Version[] =`n"                                             +
     "    u8`"{1}`";`n"                                                     +
     "`n"                                                                   +
+    "}}  // namespace internal`n"                                          +
+    "}}  // namespace _version`n"                                          +
     "}}  // namespace base`n"                                              +
     "}}  // namespace principia`n",
     $newdate.ToUniversalTime(),

geometry/pair.hpp

@@ -22,6 +22,8 @@ namespace internal_pair {
 using quantities::Difference;
 using quantities::Product;
 using quantities::Quotient;
+using namespace principia::base::_not_constructible;
+using namespace principia::base::_not_null;
 
 template<typename T1, typename T2>
 class Pair;
@@ -209,8 +211,6 @@ using internal_pair::vector_of;
 namespace internal_barycentre_calculator {
 
 using quantities::Difference;
-using namespace principia::base::_not_constructible;
-using namespace principia::base::_not_null;
 
 template<typename T1, typename T2, typename Weight>
 class BarycentreCalculator<Pair<T1, T2>, Weight> final {

journal/recorder.cpp

@@ -14,6 +14,7 @@ namespace principia {
 using base::HexadecimalEncoder;
 using namespace principia::base::_array;
 using namespace principia::base::_serialization;
+using namespace principia::base::_version;
 
 namespace journal {
 
@@ -45,8 +46,8 @@ void Recorder::Activate(base::not_null<Recorder*> const recorder) {
   active_recorder_->WriteAtConstruction(method);
   not_null<serialization::GetVersion::Out*> const out =
       get_version->mutable_out();
-  out->set_build_date(base::BuildDate);
-  out->set_version(base::Version);
+  out->set_build_date(BuildDate);
+  out->set_version(Version);
   active_recorder_->WriteAtDestruction(method);
 }
 

ksp_plugin/interface.cpp

@@ -121,6 +121,7 @@ using quantities::si::Second;
 using quantities::si::Tonne;
 using ::google::protobuf::Arena;
 using ::google::protobuf::ArenaOptions;
+using ::operator<<;
 using namespace principia::base::_array;
 using namespace principia::base::_fingerprint2011;
 using namespace principia::base::_flags;

ksp_plugin/part_subsets.cpp

@@ -9,15 +9,15 @@
 
 namespace principia {
 
-using base::make_not_null_shared;
+namespace base {
+
 using geometry::Instant;
 using ksp_plugin::Barycentric;
 using ksp_plugin::Part;
 using ksp_plugin::PileUp;
 using physics::DegreesOfFreedom;
 using physics::Ephemeris;
-
-namespace base {
+using namespace principia::base::_not_null;
 
 Subset<Part>::Properties::Properties(not_null<ksp_plugin::Part*> const part) {
   if (part->is_piled_up()) {

ksp_plugin_test/flight_plan_test.cpp

@@ -31,7 +31,6 @@ namespace principia {
 namespace ksp_plugin {
 
 using astronomy::J2000;
-using base::make_not_null_shared;
 using geometry::Barycentre;
 using geometry::Displacement;
 using geometry::Instant;