2 files changed, 31 insertions, 1 deletions
diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
index c64a6d17070..10346941153 100644
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -5540,7 +5540,7 @@ ASTNodeImporter::VisitFunctionTemplateDecl(FunctionTemplateDecl *D) {
   // Try to find a function in our own ("to") context with the same name, same
   // type, and in the same context as the function we're importing.
   if (!LexicalDC->isFunctionOrMethod()) {
-    unsigned IDNS = Decl::IDNS_Ordinary;
+    unsigned IDNS = Decl::IDNS_Ordinary | Decl::IDNS_OrdinaryFriend;
     auto FoundDecls = Importer.findDeclsInToCtx(DC, Name);
     for (auto *FoundDecl : FoundDecls) {
       if (!FoundDecl->isInIdentifierNamespace(IDNS))
diff --git a/clang/unittests/AST/ASTImporterTest.cpp b/clang/unittests/AST/ASTImporterTest.cpp
index 30bc9dc73ca..fa5384503df 100644
--- a/clang/unittests/AST/ASTImporterTest.cpp
+++ b/clang/unittests/AST/ASTImporterTest.cpp
@@ -5390,6 +5390,33 @@ TEST_P(ASTImporterOptionSpecificTestBase,
   EXPECT_EQ(0u, ToTU->getASTContext().getDiagnostics().getNumWarnings());
 }
 
+struct ImportFriendFunctionTemplates : ASTImporterOptionSpecificTestBase {};
+
+TEST_P(ImportFriendFunctionTemplates, LookupShouldFindPreviousFriend) {
+  Decl *ToTU = getToTuDecl(
+      R"(
+      class X {
+        template <typename T> friend void foo();
+      };
+      )",
+      Lang_CXX);
+  auto *Friend = FirstDeclMatcher<FunctionTemplateDecl>().match(
+      ToTU, functionTemplateDecl(hasName("foo")));
+
+  Decl *FromTU = getTuDecl(
+      R"(
+      template <typename T> void foo();
+      )",
+      Lang_CXX);
+  auto *FromFoo = FirstDeclMatcher<FunctionTemplateDecl>().match(
+      FromTU, functionTemplateDecl(hasName("foo")));
+  auto *Imported = Import(FromFoo, Lang_CXX);
+
+  // FIXME Currently chains of FunctionTemplateDecls are not implemented.
+  //EXPECT_EQ(Imported->getPreviousDecl(), Friend);
+  EXPECT_EQ(Imported, Friend);
+}
+
 INSTANTIATE_TEST_CASE_P(ParameterizedTests, ASTImporterLookupTableTest,
                         DefaultTestValuesForRunOptions, );
 
@@ -5408,6 +5435,9 @@ INSTANTIATE_TEST_CASE_P(ParameterizedTests, ASTImporterOptionSpecificTestBase,
 INSTANTIATE_TEST_CASE_P(ParameterizedTests, ImportFunctions,
                         DefaultTestValuesForRunOptions, );
 
+INSTANTIATE_TEST_CASE_P(ParameterizedTests, ImportFriendFunctionTemplates,
+                        DefaultTestValuesForRunOptions, );
+
 INSTANTIATE_TEST_CASE_P(ParameterizedTests, ImportClasses,
                         DefaultTestValuesForRunOptions, );