[ASTImporter] Fix missing implict CXXRecordDecl

Summary:
Implicit CXXRecordDecl is not added to its DeclContext during import, but in
the original AST it is. This patch fixes this.

Reviewers: xazax.hun, a.sidorin, szepet

Subscribers: rnkovacs, dkrupp, cfe-commits

Differential Revision: https://reviews.llvm.org/D46958

llvm-svn: 332588

clang/lib/AST/ASTImporter.cpp

@@ -2110,7 +2110,7 @@ Decl *ASTNodeImporter::VisitRecordDecl(RecordDecl *D) {
       D2 = D2CXX;
       D2->setAccess(D->getAccess());
       D2->setLexicalDeclContext(LexicalDC);
-      if (!DCXX->getDescribedClassTemplate())
+      if (!DCXX->getDescribedClassTemplate() || DCXX->isImplicit())
         LexicalDC->addDeclInternal(D2);
 
       Importer.Imported(D, D2);

clang/unittests/AST/ASTImporterTest.cpp

@@ -1348,7 +1348,7 @@ TEST_P(ASTImporterTestBase,
       Verifier.match(To, cxxRecordDecl(hasFieldOrder({"a", "b", "c"}))));
 }
 
-TEST_P(ASTImporterTestBase, DISABLED_ShouldImportImplicitCXXRecordDecl) {
+TEST_P(ASTImporterTestBase, ShouldImportImplicitCXXRecordDecl) {
   Decl *From, *To;
   std::tie(From, To) = getImportedDecl(
       R"(