[cxx-interop] Re-land part of 6ba7a1e. Fix an issue with extending nested namespaces across modules.

lib/ClangImporter/ImportDecl.cpp

@@ -2473,6 +2473,12 @@ namespace {
       for (auto redecl : decl->redecls())
         Impl.ImportedDecls[{redecl, getVersion()}] = enumDecl;
 
+      // Because a namespaces's decl context is the bridging header, make sure
+      // we add them to the bridging header lookup table.
+      addEntryToLookupTable(*Impl.BridgingHeaderLookupTable,
+                            const_cast<clang::NamespaceDecl *>(decl),
+                            Impl.getNameImporter());
+
       return enumDecl;
     }
 

lib/ClangImporter/ImporterImpl.h

@@ -428,9 +428,6 @@ class LLVM_LIBRARY_VISIBILITY ClangImporter::Implementation
 private:
   DiagnosticWalker Walker;
 
-  /// The Swift lookup table for the bridging header.
-  std::unique_ptr<SwiftLookupTable> BridgingHeaderLookupTable;
-
   /// The Swift lookup tables, per module.
   ///
   /// Annoyingly, we list this table early so that it gets torn down after
@@ -494,6 +491,9 @@ class LLVM_LIBRARY_VISIBILITY ClangImporter::Implementation
   llvm::SmallDenseMap<ModuleDecl *, SourceFile *> ClangSwiftAttrSourceFiles;
 
 public:
+  /// The Swift lookup table for the bridging header.
+  std::unique_ptr<SwiftLookupTable> BridgingHeaderLookupTable;
+
   /// Mapping of already-imported declarations.
   llvm::DenseMap<std::pair<const clang::Decl *, Version>, Decl *> ImportedDecls;
 

test/Interop/Cxx/modules/Inputs/bridge-header.h

@@ -0,0 +1,8 @@
+#ifndef TEST_INTEROP_CXX_MODULES_INPUTS_BRIDGE_HEADER_H
+#define TEST_INTEROP_CXX_MODULES_INPUTS_BRIDGE_HEADER_H
+
+namespace Namespace {
+struct InNamespace {};
+}
+
+#endif // TEST_INTEROP_CXX_MODULES_INPUTS_BRIDGE_HEADER_H

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

@@ -0,0 +1,4 @@
+module Namespace {
+  header "namespace.h"
+  requires cplusplus
+}

test/Interop/Cxx/modules/Inputs/namespace-extension-lib.swift

@@ -0,0 +1,13 @@
+import Namespace
+
+extension Namespace.Parent {
+  public static func test() -> Int { 42 }
+}
+
+extension Namespace.Parent.Child {
+  public static func test() -> Int { 52 }
+}
+
+extension Namespace.NestedNamespace.NestedStruct {
+  public func test() -> Int { 62 }
+}

test/Interop/Cxx/modules/Inputs/namespace.h

@@ -0,0 +1,18 @@
+#ifndef TEST_INTEROP_CXX_MODULES_INPUTS_NAMESPACE_H
+#define TEST_INTEROP_CXX_MODULES_INPUTS_NAMESPACE_H
+
+namespace Namespace {
+
+struct Parent {
+  struct Child {};
+};
+
+namespace NestedNamespace {
+
+struct NestedStruct {};
+
+} // namespace NestedNamespace
+
+} // namespace Namespace
+
+#endif // TEST_INTEROP_CXX_MODULES_INPUTS_NAMESPACE_H

test/Interop/Cxx/modules/use-namespace-extension-lib.swift

@@ -0,0 +1,24 @@
+// RUN: %empty-directory(%t)
+// RUN: cd %t
+// RUN: %target-build-swift    -I %S/Inputs -Xfrontend -enable-cxx-interop %S/Inputs/namespace-extension-lib.swift -emit-module -emit-library -static -module-name NamespaceExtensionLib
+// RUN: %target-build-swift %s -I %S/Inputs -Xfrontend -enable-cxx-interop -o %t/run -I %t/ -L %t/ -lNamespaceExtensionLib
+// RUN: %target-codesign %t/run
+// RUN: %target-run %t/run
+//
+// REQUIRES: executable_test
+// XFAIL: OS=windows-msvc
+
+import StdlibUnittest
+import Namespace
+import NamespaceExtensionLib
+
+var NamespacesTestSuite = TestSuite("Extension in library on namespace")
+
+NamespacesTestSuite.test("Call functions from extension") {
+  expectEqual(Namespace.Parent.test(), 42)
+  expectEqual(Namespace.Parent.Child.test(), 52)
+  expectEqual(Namespace.NestedNamespace.NestedStruct().test(), 62)
+}
+
+runAllTests()
+

test/Interop/Cxx/namespace/templates-module-interface.swift

@@ -47,10 +47,10 @@
 // CHECK-NEXT: }
 // CHECK-NEXT: typealias ForwardDeclaredClassTemplateOutOfLineChar = TemplatesNS1.TemplatesNS2.__CxxTemplateInstN12TemplatesNS112TemplatesNS237ForwardDeclaredClassTemplateOutOfLineIcEE
 // CHECK-NEXT: enum TemplatesNS4 {
-// CHECK-NEXT:   struct __CxxTemplateInstN12TemplatesNS417HasSpecializationIcEE {
+// CHECK-NEXT:   struct __CxxTemplateInstN12TemplatesNS417HasSpecializationIiEE {
 // CHECK-NEXT:     init()
 // CHECK-NEXT:   }
-// CHECK-NEXT:   struct __CxxTemplateInstN12TemplatesNS417HasSpecializationIiEE {
+// CHECK-NEXT:   struct __CxxTemplateInstN12TemplatesNS417HasSpecializationIcEE {
 // CHECK-NEXT:     init()
 // CHECK-NEXT:   }
 // CHECK-NEXT:   struct HasSpecialization<> {