[ASTImporter] Load external Decls when getting field index.

Summary:
At equality check of fields without name the index of fields is compared.
At determining the index of a field all fields of the parent context
should be loaded from external source to find the field at all.

Reviewers: a.sidorin, a_sidorin, r.stahl

Reviewed By: a.sidorin

Subscribers: martong, cfe-commits

Differential Revision: https://reviews.llvm.org/D49796

llvm-svn: 339226

1 files changed, 34 insertions, 0 deletions

diff --git a/clang/unittests/AST/ASTImporterTest.cpp b/clang/unittests/AST/ASTImporterTest.cpp
index 04006a0bea3..2690f4e5f1f 100644
--- a/clang/unittests/AST/ASTImporterTest.cpp
+++ b/clang/unittests/AST/ASTImporterTest.cpp
@@ -2641,6 +2641,40 @@ TEST_P(ASTImporterTestBase, ImportUnnamedStructsWithRecursingField) {
       R1, recordDecl(has(fieldDecl(hasName("next"))))));
 }
 
+TEST_P(ASTImporterTestBase, ImportUnnamedFieldsInCorrectOrder) {
+  Decl *FromTU = getTuDecl(
+      R"(
+      void f(int X, int Y, bool Z) {
+        (void)[X, Y, Z] { (void)Z; };
+      }
+      )",
+      Lang_CXX11, "input0.cc");
+  auto *FromF = FirstDeclMatcher<FunctionDecl>().match(
+      FromTU, functionDecl(hasName("f")));
+  auto *ToF = cast_or_null<FunctionDecl>(Import(FromF, Lang_CXX11));
+  EXPECT_TRUE(ToF);
+
+  CXXRecordDecl *FromLambda =
+      cast<LambdaExpr>(cast<CStyleCastExpr>(cast<CompoundStmt>(
+          FromF->getBody())->body_front())->getSubExpr())->getLambdaClass();
+
+  auto *ToLambda = cast_or_null<CXXRecordDecl>(Import(FromLambda, Lang_CXX11));
+  EXPECT_TRUE(ToLambda);
+
+  // Check if the fields of the lambda class are imported in correct order.
+  unsigned FromIndex = 0u;
+  for (auto *FromField : FromLambda->fields()) {
+    ASSERT_FALSE(FromField->getDeclName());
+    auto *ToField = cast_or_null<FieldDecl>(Import(FromField, Lang_CXX11));
+    EXPECT_TRUE(ToField);
+    unsigned ToIndex = ASTImporter::getFieldIndex(ToField);
+    EXPECT_EQ(ToIndex, FromIndex + 1);
+    ++FromIndex;
+  }
+
+  EXPECT_EQ(FromIndex, 3u);
+}
+
 struct DeclContextTest : ASTImporterTestBase {};
 
 TEST_P(DeclContextTest, removeDeclOfClassTemplateSpecialization) {