#include "clang/AST/ASTContext.h"
#include "clang/ASTMatchers/ASTMatchers.h"
#include "clang/AST/ASTStructuralEquivalence.h"
#include "clang/Frontend/ASTUnit.h"
#include "clang/Tooling/Tooling.h"

#include "Language.h"
#include "DeclMatcher.h"

#include "gtest/gtest.h"

namespace clang {
namespace ast_matchers {

using std::get;

struct StructuralEquivalenceTest : ::testing::Test {
  std::unique_ptr<ASTUnit> AST0, AST1;
  std::string Code0, Code1; // Buffers for SourceManager

  // Get a pair of node pointers into the synthesized AST from the given code
  // snippets. To determine the returned node, a separate matcher is specified
  // for both snippets. The first matching node is returned.
  template <typename NodeType, typename MatcherType>
  std::tuple<NodeType *, NodeType *> makeDecls(
      const std::string &SrcCode0, const std::string &SrcCode1, Language Lang,
      const MatcherType &Matcher0, const MatcherType &Matcher1) {
    this->Code0 = SrcCode0;
    this->Code1 = SrcCode1;
    ArgVector Args = getBasicRunOptionsForLanguage(Lang);

    const char *const InputFileName = "input.cc";

    AST0 = tooling::buildASTFromCodeWithArgs(Code0, Args, InputFileName);
    AST1 = tooling::buildASTFromCodeWithArgs(Code1, Args, InputFileName);

    NodeType *D0 = FirstDeclMatcher<NodeType>().match(
        AST0->getASTContext().getTranslationUnitDecl(), Matcher0);
    NodeType *D1 = FirstDeclMatcher<NodeType>().match(
        AST1->getASTContext().getTranslationUnitDecl(), Matcher1);

    return std::make_tuple(D0, D1);
  }

  std::tuple<TranslationUnitDecl *, TranslationUnitDecl *> makeTuDecls(
      const std::string &SrcCode0, const std::string &SrcCode1, Language Lang) {
    this->Code0 = SrcCode0;
    this->Code1 = SrcCode1;
    ArgVector Args = getBasicRunOptionsForLanguage(Lang);

    const char *const InputFileName = "input.cc";

    AST0 = tooling::buildASTFromCodeWithArgs(Code0, Args, InputFileName);
    AST1 = tooling::buildASTFromCodeWithArgs(Code1, Args, InputFileName);

    return std::make_tuple(AST0->getASTContext().getTranslationUnitDecl(),
                           AST1->getASTContext().getTranslationUnitDecl());
  }

  // Get a pair of node pointers into the synthesized AST from the given code
  // snippets. The same matcher is used for both snippets.
  template <typename NodeType, typename MatcherType>
  std::tuple<NodeType *, NodeType *> makeDecls(
      const std::string &SrcCode0, const std::string &SrcCode1, Language Lang,
      const MatcherType &AMatcher) {
    return makeDecls<NodeType, MatcherType>(
          SrcCode0, SrcCode1, Lang, AMatcher, AMatcher);
  }

  // Get a pair of Decl pointers to the synthesized declarations from the given
  // code snippets. We search for the first NamedDecl with given name in both
  // snippets.
  std::tuple<NamedDecl *, NamedDecl *> makeNamedDecls(
      const std::string &SrcCode0, const std::string &SrcCode1,
      Language Lang, const char *const Identifier = "foo") {
    auto Matcher = namedDecl(hasName(Identifier));
    return makeDecls<NamedDecl>(SrcCode0, SrcCode1, Lang, Matcher);
  }

  bool testStructuralMatch(Decl *D0, Decl *D1) {
    llvm::DenseSet<std::pair<Decl *, Decl *>> NonEquivalentDecls01;
    llvm::DenseSet<std::pair<Decl *, Decl *>> NonEquivalentDecls10;
    StructuralEquivalenceContext Ctx01(
        D0->getASTContext(), D1->getASTContext(),
        NonEquivalentDecls01, StructuralEquivalenceKind::Default, false, false);
    StructuralEquivalenceContext Ctx10(
        D1->getASTContext(), D0->getASTContext(),
        NonEquivalentDecls10, StructuralEquivalenceKind::Default, false, false);
    bool Eq01 = Ctx01.IsEquivalent(D0, D1);
    bool Eq10 = Ctx10.IsEquivalent(D1, D0);
    EXPECT_EQ(Eq01, Eq10);
    return Eq01;
  }

  bool testStructuralMatch(std::tuple<Decl *, Decl *> t) {
    return testStructuralMatch(get<0>(t), get<1>(t));
  }
};

TEST_F(StructuralEquivalenceTest, Int) {
  auto Decls = makeNamedDecls("int foo;", "int foo;", Lang_CXX);
  EXPECT_TRUE(testStructuralMatch(Decls));
}

TEST_F(StructuralEquivalenceTest, IntVsSignedInt) {
  auto Decls = makeNamedDecls("int foo;", "signed int foo;", Lang_CXX);
  EXPECT_TRUE(testStructuralMatch(Decls));
}

TEST_F(StructuralEquivalenceTest, Char) {
  auto Decls = makeNamedDecls("char foo;", "char foo;", Lang_CXX);
  EXPECT_TRUE(testStructuralMatch(Decls));
}

// This test is disabled for now.
// FIXME Whether this is equivalent is dependendant on the target.
TEST_F(StructuralEquivalenceTest, DISABLED_CharVsSignedChar) {
  auto Decls = makeNamedDecls("char foo;", "signed char foo;", Lang_CXX);
  EXPECT_FALSE(testStructuralMatch(Decls));
}

TEST_F(StructuralEquivalenceTest, ForwardRecordDecl) {
  auto Decls = makeNamedDecls("struct foo;", "struct foo;", Lang_CXX);
  EXPECT_TRUE(testStructuralMatch(Decls));
}

TEST_F(StructuralEquivalenceTest, IntVsSignedIntInStruct) {
  auto Decls = makeNamedDecls("struct foo { int x; };",
                              "struct foo { signed int x; };", Lang_CXX);
  EXPECT_TRUE(testStructuralMatch(Decls));
}

TEST_F(StructuralEquivalenceTest, CharVsSignedCharInStruct) {
  auto Decls = makeNamedDecls("struct foo { char x; };",
                              "struct foo { signed char x; };", Lang_CXX);
  EXPECT_FALSE(testStructuralMatch(Decls));
}

TEST_F(StructuralEquivalenceTest, IntVsSignedIntTemplateSpec) {
  auto Decls = makeDecls<ClassTemplateSpecializationDecl>(
      R"(template <class T> struct foo; template<> struct foo<int>{};)",
      R"(template <class T> struct foo; template<> struct foo<signed int>{};)",
      Lang_CXX,
      classTemplateSpecializationDecl());
  auto Spec0 = get<0>(Decls);
  auto Spec1 = get<1>(Decls);
  EXPECT_TRUE(testStructuralMatch(Spec0, Spec1));
}

TEST_F(StructuralEquivalenceTest, CharVsSignedCharTemplateSpec) {
  auto Decls = makeDecls<ClassTemplateSpecializationDecl>(
      R"(template <class T> struct foo; template<> struct foo<char>{};)",
      R"(template <class T> struct foo; template<> struct foo<signed char>{};)",
      Lang_CXX,
      classTemplateSpecializationDecl());
  auto Spec0 = get<0>(Decls);
  auto Spec1 = get<1>(Decls);
  EXPECT_FALSE(testStructuralMatch(Spec0, Spec1));
}

TEST_F(StructuralEquivalenceTest, CharVsSignedCharTemplateSpecWithInheritance) {
  auto Decls = makeDecls<ClassTemplateSpecializationDecl>(
      R"(
      struct true_type{};
      template <class T> struct foo;
      template<> struct foo<char> : true_type {};
      )",
      R"(
      struct true_type{};
      template <class T> struct foo;
      template<> struct foo<signed char> : true_type {};
      )",
      Lang_CXX,
      classTemplateSpecializationDecl());
  EXPECT_FALSE(testStructuralMatch(Decls));
}

// This test is disabled for now.
// FIXME Enable it, once the check is implemented.
TEST_F(StructuralEquivalenceTest, DISABLED_WrongOrderInNamespace) {
  auto Code =
      R"(
      namespace NS {
      template <class T> class Base {
          int a;
      };
      class Derived : Base<Derived> {
      };
      }
      void foo(NS::Derived &);
      )";
  auto Decls = makeNamedDecls(Code, Code, Lang_CXX);

  NamespaceDecl *NS =
      LastDeclMatcher<NamespaceDecl>().match(get<1>(Decls), namespaceDecl());
  ClassTemplateDecl *TD = LastDeclMatcher<ClassTemplateDecl>().match(
      get<1>(Decls), classTemplateDecl(hasName("Base")));

  // Reorder the decls, move the TD to the last place in the DC.
  NS->removeDecl(TD);
  NS->addDeclInternal(TD);

  EXPECT_FALSE(testStructuralMatch(Decls));
}

TEST_F(StructuralEquivalenceTest, WrongOrderOfFieldsInClass) {
  auto Code = "class X { int a; int b; };";
  auto Decls = makeNamedDecls(Code, Code, Lang_CXX, "X");

  CXXRecordDecl *RD = FirstDeclMatcher<CXXRecordDecl>().match(
      get<1>(Decls), cxxRecordDecl(hasName("X")));
  FieldDecl *FD =
      FirstDeclMatcher<FieldDecl>().match(get<1>(Decls), fieldDecl(hasName("a")));

  // Reorder the FieldDecls
  RD->removeDecl(FD);
  RD->addDeclInternal(FD);

  EXPECT_FALSE(testStructuralMatch(Decls));
}

struct StructuralEquivalenceFunctionTest : StructuralEquivalenceTest {
};

TEST_F(StructuralEquivalenceFunctionTest, TemplateVsNonTemplate) {
  auto t = makeNamedDecls(
      "void foo();",
      "template<class T> void foo();",
      Lang_CXX);
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceFunctionTest, ParamConstWithRef) {
  auto t = makeNamedDecls("void foo(int&);",
                          "void foo(const int&);", Lang_CXX);
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceFunctionTest, ParamConstSimple) {
  auto t = makeNamedDecls("void foo(int);",
                          "void foo(const int);", Lang_CXX);
  EXPECT_TRUE(testStructuralMatch(t));
  // consider this OK
}

TEST_F(StructuralEquivalenceFunctionTest, Throw) {
  auto t = makeNamedDecls("void foo();",
                          "void foo() throw();", Lang_CXX);
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceFunctionTest, Noexcept) {
  auto t = makeNamedDecls("void foo();",
                          "void foo() noexcept;", Lang_CXX11);
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceFunctionTest, ThrowVsNoexcept) {
  auto t = makeNamedDecls("void foo() throw();",
                          "void foo() noexcept;", Lang_CXX11);
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceFunctionTest, ThrowVsNoexceptFalse) {
  auto t = makeNamedDecls("void foo() throw();",
                          "void foo() noexcept(false);", Lang_CXX11);
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceFunctionTest, ThrowVsNoexceptTrue) {
  auto t = makeNamedDecls("void foo() throw();",
                          "void foo() noexcept(true);", Lang_CXX11);
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceFunctionTest, DISABLED_NoexceptNonMatch) {
  // The expression is not checked yet.
  auto t = makeNamedDecls("void foo() noexcept(false);",
                          "void foo() noexcept(true);", Lang_CXX11);
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceFunctionTest, NoexceptMatch) {
  auto t = makeNamedDecls("void foo() noexcept(false);",
                          "void foo() noexcept(false);", Lang_CXX11);
  EXPECT_TRUE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceFunctionTest, NoexceptVsNoexceptFalse) {
  auto t = makeNamedDecls("void foo() noexcept;",
                          "void foo() noexcept(false);", Lang_CXX11);
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceFunctionTest, NoexceptVsNoexceptTrue) {
  auto t = makeNamedDecls("void foo() noexcept;",
                          "void foo() noexcept(true);", Lang_CXX11);
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceFunctionTest, ReturnType) {
  auto t = makeNamedDecls("char foo();",
                          "int foo();", Lang_CXX);
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceFunctionTest, ReturnConst) {
  auto t = makeNamedDecls("char foo();",
                          "const char foo();", Lang_CXX);
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceFunctionTest, ReturnRef) {
  auto t = makeNamedDecls("char &foo();",
                          "char &&foo();", Lang_CXX11);
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceFunctionTest, ParamCount) {
  auto t = makeNamedDecls("void foo(int);",
                          "void foo(int, int);", Lang_CXX);
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceFunctionTest, ParamType) {
  auto t = makeNamedDecls("void foo(int);",
                          "void foo(char);", Lang_CXX);
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceFunctionTest, ParamName) {
  auto t = makeNamedDecls("void foo(int a);",
                          "void foo(int b);", Lang_CXX);
  EXPECT_TRUE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceFunctionTest, Variadic) {
  auto t = makeNamedDecls("void foo(int x...);",
                          "void foo(int x);", Lang_CXX);
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceFunctionTest, ParamPtr) {
  auto t = makeNamedDecls("void foo(int *);",
                          "void foo(int);", Lang_CXX);
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceFunctionTest, NameInParen) {
  auto t = makeNamedDecls(
      "void ((foo))();",
      "void foo();",
      Lang_CXX);
  EXPECT_TRUE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceFunctionTest, NameInParenWithExceptionSpec) {
  auto t = makeNamedDecls(
      "void (foo)() throw(int);",
      "void (foo)() noexcept;",
      Lang_CXX11);
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceFunctionTest, NameInParenWithConst) {
  auto t = makeNamedDecls(
      "struct A { void (foo)() const; };",
      "struct A { void (foo)(); };",
      Lang_CXX11);
  EXPECT_FALSE(testStructuralMatch(t));
}

struct StructuralEquivalenceCXXMethodTest : StructuralEquivalenceTest {
};

TEST_F(StructuralEquivalenceCXXMethodTest, Virtual) {
  auto t = makeDecls<CXXMethodDecl>(
      "struct X { void foo(); };",
      "struct X { virtual void foo(); };", Lang_CXX,
      cxxMethodDecl(hasName("foo")));
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceCXXMethodTest, Pure) {
  auto t = makeNamedDecls("struct X { virtual void foo(); };",
                          "struct X { virtual void foo() = 0; };", Lang_CXX);
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceCXXMethodTest, DISABLED_Final) {
  // The final-ness is not checked yet.
  auto t = makeNamedDecls("struct X { virtual void foo(); };",
                          "struct X { virtual void foo() final; };", Lang_CXX);
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceCXXMethodTest, Const) {
  auto t = makeNamedDecls("struct X { void foo(); };",
                          "struct X { void foo() const; };", Lang_CXX);
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceCXXMethodTest, Static) {
  auto t = makeNamedDecls("struct X { void foo(); };",
                          "struct X { static void foo(); };", Lang_CXX);
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceCXXMethodTest, Ref1) {
  auto t = makeNamedDecls("struct X { void foo(); };",
                          "struct X { void foo() &&; };", Lang_CXX11);
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceCXXMethodTest, Ref2) {
  auto t = makeNamedDecls("struct X { void foo() &; };",
                          "struct X { void foo() &&; };", Lang_CXX11);
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceCXXMethodTest, AccessSpecifier) {
  auto t = makeDecls<CXXMethodDecl>(
      "struct X { public: void foo(); };",
      "struct X { private: void foo(); };", Lang_CXX,
      cxxMethodDecl(hasName("foo")));
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceCXXMethodTest, Delete) {
  auto t = makeNamedDecls("struct X { void foo(); };",
                          "struct X { void foo() = delete; };", Lang_CXX11);
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceCXXMethodTest, Constructor) {
  auto t = makeDecls<FunctionDecl>(
      "void foo();", "struct foo { foo(); };", Lang_CXX,
      functionDecl(hasName("foo")), cxxConstructorDecl(hasName("foo")));
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceCXXMethodTest, ConstructorParam) {
  auto t = makeDecls<CXXConstructorDecl>("struct X { X(); };",
                                         "struct X { X(int); };", Lang_CXX,
                                         cxxConstructorDecl(hasName("X")));
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceCXXMethodTest, ConstructorExplicit) {
  auto t = makeDecls<CXXConstructorDecl>("struct X { X(int); };",
                                         "struct X { explicit X(int); };",
                                         Lang_CXX11,
                                         cxxConstructorDecl(hasName("X")));
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceCXXMethodTest, ConstructorDefault) {
  auto t = makeDecls<CXXConstructorDecl>("struct X { X(); };",
                                         "struct X { X() = default; };",
                                         Lang_CXX11,
                                         cxxConstructorDecl(hasName("X")));
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceCXXMethodTest, Conversion) {
  auto t = makeDecls<CXXConversionDecl>("struct X { operator bool(); };",
                                        "struct X { operator char(); };",
                                         Lang_CXX11,
                                         cxxConversionDecl());
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceCXXMethodTest, Operator) {
  auto t = makeDecls<FunctionDecl>(
      "struct X { int operator +(int); };",
      "struct X { int operator -(int); };", Lang_CXX,
      functionDecl(hasOverloadedOperatorName("+")),
      functionDecl(hasOverloadedOperatorName("-")));
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceCXXMethodTest, OutOfClass1) {
  auto t = makeDecls<FunctionDecl>(
      "struct X { virtual void f(); }; void X::f() { }",
      "struct X { virtual void f() { }; };",
      Lang_CXX,
      functionDecl(allOf(hasName("f"), isDefinition())));
  EXPECT_TRUE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceCXXMethodTest, OutOfClass2) {
  auto t = makeDecls<FunctionDecl>(
      "struct X { virtual void f(); }; void X::f() { }",
      "struct X { void f(); }; void X::f() { }",
      Lang_CXX,
      functionDecl(allOf(hasName("f"), isDefinition())));
  EXPECT_FALSE(testStructuralMatch(t));
}

struct StructuralEquivalenceRecordTest : StructuralEquivalenceTest {
  // FIXME Use a common getRecordDecl with ASTImporterTest.cpp!
  RecordDecl *getRecordDecl(FieldDecl *FD) {
    auto *ET = cast<ElaboratedType>(FD->getType().getTypePtr());
    return cast<RecordType>(ET->getNamedType().getTypePtr())->getDecl();
  };
};

TEST_F(StructuralEquivalenceRecordTest, Name) {
  auto t = makeDecls<CXXRecordDecl>(
      "struct A{ };",
      "struct B{ };",
      Lang_CXX,
      cxxRecordDecl(hasName("A")),
      cxxRecordDecl(hasName("B")));
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceRecordTest, Fields) {
  auto t = makeNamedDecls(
      "struct foo{ int x; };",
      "struct foo{ char x; };",
      Lang_CXX);
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceRecordTest, DISABLED_Methods) {
  // Currently, methods of a class are not checked at class equivalence.
  auto t = makeNamedDecls(
      "struct foo{ int x(); };",
      "struct foo{ char x(); };",
      Lang_CXX);
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceRecordTest, Bases) {
  auto t = makeNamedDecls(
      "struct A{ }; struct foo: A { };",
      "struct B{ }; struct foo: B { };",
      Lang_CXX);
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceRecordTest, InheritanceVirtual) {
  auto t = makeNamedDecls(
      "struct A{ }; struct foo: A { };",
      "struct A{ }; struct foo: virtual A { };",
      Lang_CXX);
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceRecordTest, DISABLED_InheritanceType) {
  // Access specifier in inheritance is not checked yet.
  auto t = makeNamedDecls(
      "struct A{ }; struct foo: public A { };",
      "struct A{ }; struct foo: private A { };",
      Lang_CXX);
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceRecordTest, Match) {
  auto Code = R"(
      struct A{ };
      struct B{ };
      struct foo: A, virtual B {
        void x();
        int a;
      };
      )";
  auto t = makeNamedDecls(Code, Code, Lang_CXX);
  EXPECT_TRUE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceRecordTest, UnnamedRecordsShouldBeInequivalent) {
  auto t = makeTuDecls(
      R"(
      struct A {
        struct {
          struct A *next;
        } entry0;
        struct {
          struct A *next;
        } entry1;
      };
      )",
      "", Lang_C);
  auto *TU = get<0>(t);
  auto *Entry0 =
      FirstDeclMatcher<FieldDecl>().match(TU, fieldDecl(hasName("entry0")));
  auto *Entry1 =
      FirstDeclMatcher<FieldDecl>().match(TU, fieldDecl(hasName("entry1")));
  auto *R0 = getRecordDecl(Entry0);
  auto *R1 = getRecordDecl(Entry1);

  ASSERT_NE(R0, R1);
  EXPECT_TRUE(testStructuralMatch(R0, R0));
  EXPECT_TRUE(testStructuralMatch(R1, R1));
  EXPECT_FALSE(testStructuralMatch(R0, R1));
}

TEST_F(StructuralEquivalenceRecordTest,
       UnnamedRecordsShouldBeInequivalentEvenIfTheSecondIsBeingDefined) {
  auto Code =
      R"(
      struct A {
        struct {
          struct A *next;
        } entry0;
        struct {
          struct A *next;
        } entry1;
      };
      )";
  auto t = makeTuDecls(Code, Code, Lang_C);

  auto *FromTU = get<0>(t);
  auto *Entry1 =
      FirstDeclMatcher<FieldDecl>().match(FromTU, fieldDecl(hasName("entry1")));

  auto *ToTU = get<1>(t);
  auto *Entry0 =
      FirstDeclMatcher<FieldDecl>().match(ToTU, fieldDecl(hasName("entry0")));
  auto *A =
      FirstDeclMatcher<RecordDecl>().match(ToTU, recordDecl(hasName("A")));
  A->startDefinition(); // Set isBeingDefined, getDefinition() will return a
                        // nullptr. This may be the case during ASTImport.

  auto *R0 = getRecordDecl(Entry0);
  auto *R1 = getRecordDecl(Entry1);

  ASSERT_NE(R0, R1);
  EXPECT_TRUE(testStructuralMatch(R0, R0));
  EXPECT_TRUE(testStructuralMatch(R1, R1));
  EXPECT_FALSE(testStructuralMatch(R0, R1));
}

TEST_F(StructuralEquivalenceRecordTest, TemplateVsNonTemplate) {
  auto t = makeDecls<CXXRecordDecl>(
      "struct A { };",
      "template<class T> struct A { };",
      Lang_CXX,
      cxxRecordDecl(hasName("A")));
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceRecordTest,
    FwdDeclRecordShouldBeEqualWithFwdDeclRecord) {
  auto t = makeNamedDecls("class foo;", "class foo;", Lang_CXX11);
  EXPECT_TRUE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceRecordTest,
       FwdDeclRecordShouldBeEqualWithRecordWhichHasDefinition) {
  auto t =
      makeNamedDecls("class foo;", "class foo { int A; };", Lang_CXX11);
  EXPECT_TRUE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceRecordTest,
       RecordShouldBeEqualWithRecordWhichHasDefinition) {
  auto t = makeNamedDecls("class foo { int A; };", "class foo { int A; };",
                          Lang_CXX11);
  EXPECT_TRUE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceRecordTest, RecordsWithDifferentBody) {
  auto t = makeNamedDecls("class foo { int B; };", "class foo { int A; };",
                          Lang_CXX11);
  EXPECT_FALSE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceTest, CompareSameDeclWithMultiple) {
  auto t = makeNamedDecls(
      "struct A{ }; struct B{ }; void foo(A a, A b);",
      "struct A{ }; struct B{ }; void foo(A a, B b);",
      Lang_CXX);
  EXPECT_FALSE(testStructuralMatch(t));
}

struct StructuralEquivalenceEnumTest : StructuralEquivalenceTest {};

TEST_F(StructuralEquivalenceEnumTest, FwdDeclEnumShouldBeEqualWithFwdDeclEnum) {
  auto t = makeNamedDecls("enum class foo;", "enum class foo;", Lang_CXX11);
  EXPECT_TRUE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceEnumTest,
       FwdDeclEnumShouldBeEqualWithEnumWhichHasDefinition) {
  auto t =
      makeNamedDecls("enum class foo;", "enum class foo { A };", Lang_CXX11);
  EXPECT_TRUE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceEnumTest,
       EnumShouldBeEqualWithEnumWhichHasDefinition) {
  auto t = makeNamedDecls("enum class foo { A };", "enum class foo { A };",
                          Lang_CXX11);
  EXPECT_TRUE(testStructuralMatch(t));
}

TEST_F(StructuralEquivalenceEnumTest, EnumsWithDifferentBody) {
  auto t = makeNamedDecls("enum class foo { B };", "enum class foo { A };",
                          Lang_CXX11);
  EXPECT_FALSE(testStructuralMatch(t));
}


} // end namespace ast_matchers
} // end namespace clang