Import default template args

lib/AST/ASTImporter.cpp

@@ -4172,9 +4172,7 @@ Decl *ASTNodeImporter::VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D) {
   // For template arguments, we adopt the translation unit as our declaration
   // context. This context will be fixed when the actual template declaration
   // is created.
-
-  // FIXME: Import default argument.
-  return TemplateTypeParmDecl::Create(Importer.getToContext(),
+  auto ToD = TemplateTypeParmDecl::Create(Importer.getToContext(),
                               Importer.getToContext().getTranslationUnitDecl(),
                                       Importer.Import(D->getLocStart()),
                                       Importer.Import(D->getLocation()),
@@ -4183,6 +4181,13 @@ Decl *ASTNodeImporter::VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D) {
                                       Importer.Import(D->getIdentifier()),
                                       D->wasDeclaredWithTypename(),
                                       D->isParameterPack());
+  Importer.Imported(D, ToD);
+  if (D->hasDefaultArgument()) {
+    TypeSourceInfo *ToDefaultArgInfo =
+        Importer.Import(D->getDefaultArgumentInfo());
+    ToD->setDefaultArgument(ToDefaultArgInfo);
+  }
+  return ToD;
 }
 
 Decl *

unittests/AST/ASTImporterTest.cpp

@@ -2392,5 +2392,113 @@ long b = strtol(&a);
   EXPECT_EQ(DeclCounter<UsingShadowDecl>().match(ToTU, usingShadowDecl()), 1u);
 }
 
+TEST_F(Fixture, ShouldImportDefaultTemplateArg) {
+  Decl *FromTU =
+      getTuDecl("template <class T=int> struct X{};", Lang_CXX, "input0.cc");
+  auto FromD =
+      FirstDeclMatcher<ClassTemplateDecl>().match(FromTU, classTemplateDecl());
+
+  {
+    auto TPL = FromD->getTemplateParameters();
+    ASSERT_EQ((TPL->end() - TPL->begin()), 1);
+    TemplateTypeParmDecl *ParmD = cast<TemplateTypeParmDecl>(*(TPL->begin()));
+    ASSERT_TRUE(ParmD->hasDefaultArgument());
+  }
+
+  {
+    auto ToD = cast<ClassTemplateDecl>(Import(FromD, Lang_CXX));
+    auto TPL = ToD->getTemplateParameters();
+    ASSERT_EQ((TPL->end() - TPL->begin()), 1);
+    TemplateTypeParmDecl *ParmD = cast<TemplateTypeParmDecl>(*(TPL->begin()));
+    EXPECT_TRUE(ParmD->hasDefaultArgument());
+  }
+}
+
+TEST_F(Fixture, ShouldImportDefaultTemplateArgs) {
+  Decl *FromTU = getTuDecl("template <class T0=int, class T1=char> struct X{};",
+                           Lang_CXX, "input0.cc");
+  auto FromD =
+      FirstDeclMatcher<ClassTemplateDecl>().match(FromTU, classTemplateDecl());
+
+  {
+    auto TPL = FromD->getTemplateParameters();
+    ASSERT_EQ((TPL->end() - TPL->begin()), 2);
+    auto it = TPL->begin();
+    TemplateTypeParmDecl *ParmD0 = cast<TemplateTypeParmDecl>(*it++);
+    ASSERT_TRUE(ParmD0->hasDefaultArgument());
+    TemplateTypeParmDecl *ParmD1 = cast<TemplateTypeParmDecl>(*it);
+    ASSERT_TRUE(ParmD1->hasDefaultArgument());
+  }
+
+  {
+    auto ToD = cast<ClassTemplateDecl>(Import(FromD, Lang_CXX));
+    auto TPL = ToD->getTemplateParameters();
+    ASSERT_EQ((TPL->end() - TPL->begin()), 2);
+    auto it = TPL->begin();
+    TemplateTypeParmDecl *ParmD0 = cast<TemplateTypeParmDecl>(*it++);
+    EXPECT_TRUE(ParmD0->hasDefaultArgument());
+    TemplateTypeParmDecl *ParmD1 = cast<TemplateTypeParmDecl>(*it);
+    EXPECT_TRUE(ParmD1->hasDefaultArgument());
+  }
+}
+
+TEST_F(Fixture, ShouldImportDefaultTemplateArgFromFwdDecl) {
+  Decl *FromTU = getTuDecl(
+      R"(
+      template<typename T0, typename T1 = int> class A;
+      template<typename T0 = int, typename T1> class A;
+      )",
+      Lang_CXX, "input0.cc");
+  auto FromD =
+      LastDeclMatcher<ClassTemplateDecl>().match(FromTU, classTemplateDecl());
+
+  {
+    auto TPL = FromD->getTemplateParameters();
+    ASSERT_EQ((TPL->end() - TPL->begin()), 2);
+    auto it = TPL->begin();
+    TemplateTypeParmDecl *ParmD0 = cast<TemplateTypeParmDecl>(*it++);
+    ASSERT_TRUE(ParmD0->hasDefaultArgument());
+    TemplateTypeParmDecl *ParmD1 = cast<TemplateTypeParmDecl>(*it);
+    ASSERT_TRUE(ParmD1->hasDefaultArgument());
+  }
+
+  {
+    auto ToD = cast<ClassTemplateDecl>(Import(FromD, Lang_CXX));
+    auto TPL = ToD->getTemplateParameters();
+    ASSERT_EQ((TPL->end() - TPL->begin()), 2);
+    auto it = TPL->begin();
+    TemplateTypeParmDecl *ParmD0 = cast<TemplateTypeParmDecl>(*it++);
+    EXPECT_TRUE(ParmD0->hasDefaultArgument());
+    TemplateTypeParmDecl *ParmD1 = cast<TemplateTypeParmDecl>(*it);
+    EXPECT_TRUE(ParmD1->hasDefaultArgument());
+  }
+}
+
+const internal::VariadicDynCastAllOfMatcher<Decl, VarTemplateDecl>
+    varTemplateDecl;
+
+TEST_F(Fixture, ShouldImportDefaultTemplateArgOfVariableTemplate) {
+  Decl *FromTU = getTuDecl(
+      "template<class T=double> constexpr T pi = T(3.1415926535897932385L);",
+      Lang_CXX14, "input0.cc");
+  auto FromD =
+      FirstDeclMatcher<VarTemplateDecl>().match(FromTU, varTemplateDecl());
+
+  {
+    auto TPL = FromD->getTemplateParameters();
+    ASSERT_EQ((TPL->end() - TPL->begin()), 1);
+    TemplateTypeParmDecl *ParmD = cast<TemplateTypeParmDecl>(*(TPL->begin()));
+    ASSERT_TRUE(ParmD->hasDefaultArgument());
+  }
+
+  {
+    auto ToD = cast<VarTemplateDecl>(Import(FromD, Lang_CXX));
+    auto TPL = ToD->getTemplateParameters();
+    ASSERT_EQ((TPL->end() - TPL->begin()), 1);
+    TemplateTypeParmDecl *ParmD = cast<TemplateTypeParmDecl>(*(TPL->begin()));
+    EXPECT_TRUE(ParmD->hasDefaultArgument());
+  }
+}
+
 } // end namespace ast_matchers
 } // end namespace clang

unittests/AST/Language.h

@@ -21,6 +21,7 @@ enum Language {
     Lang_C89,
     Lang_CXX,
     Lang_CXX11,
+    Lang_CXX14,
     Lang_OpenCL,
     Lang_OBJCXX
 };
@@ -42,6 +43,9 @@ void getLangArgs(Language Lang, StringVector &Args) {
   case Lang_CXX11:
     Args.push_back("-std=c++11");
     break;
+  case Lang_CXX14:
+    Args.push_back("-std=c++14");
+    break;
   case Lang_OpenCL:
   case Lang_OBJCXX:
     break;

unittests/AST/MatchVerifier.h

@@ -105,6 +105,10 @@ testing::AssertionResult MatchVerifier<NodeType>::match(
     Args.push_back("-std=c++11");
     FileName = "input.cc";
     break;
+  case Lang_CXX14:
+    Args.push_back("-std=c++14");
+    FileName = "input.cc";
+    break;
   case Lang_OpenCL:
     FileName = "input.cl";
     break;