1 files changed, 33 insertions, 0 deletions
diff --git a/clang/unittests/AST/ASTImporterTest.cpp b/clang/unittests/AST/ASTImporterTest.cpp
index debcfe67d96..9eec1d20bac 100644
--- a/clang/unittests/AST/ASTImporterTest.cpp
+++ b/clang/unittests/AST/ASTImporterTest.cpp
@@ -1431,6 +1431,39 @@ TEST_P(ASTImporterTestBase,
       MatchVerifier<Decl>{}.match(To->getTranslationUnitDecl(), Pattern));
 }
 
+TEST_P(ASTImporterTestBase, ImportDefinitionOfClassTemplateAfterFwdDecl) {
+  {
+    Decl *FromTU = getTuDecl(
+        R"(
+            template <typename T>
+            struct B;
+            )",
+        Lang_CXX, "input0.cc");
+    auto *FromD = FirstDeclMatcher<ClassTemplateDecl>().match(
+        FromTU, classTemplateDecl(hasName("B")));
+
+    Import(FromD, Lang_CXX);
+  }
+
+  {
+    Decl *FromTU = getTuDecl(
+        R"(
+            template <typename T>
+            struct B {
+              void f();
+            };
+            )",
+        Lang_CXX, "input1.cc");
+    FunctionDecl *FromD = FirstDeclMatcher<FunctionDecl>().match(
+        FromTU, functionDecl(hasName("f")));
+    Import(FromD, Lang_CXX);
+    auto *FromCTD = FirstDeclMatcher<ClassTemplateDecl>().match(
+        FromTU, classTemplateDecl(hasName("B")));
+    auto *ToCTD = cast<ClassTemplateDecl>(Import(FromCTD, Lang_CXX));
+    EXPECT_TRUE(ToCTD->isThisDeclarationADefinition());
+  }
+}
+
 INSTANTIATE_TEST_CASE_P(
     ParameterizedTests, ASTImporterTestBase,
     ::testing::Values(ArgVector(), ArgVector{"-fdelayed-template-parsing"}),);