unittests/Support/Casting.cpp - llvm-project/llvm - Git at Google

 //===---------- llvm/unittest/Support/Casting.cpp - Casting tests ---------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//

 #include "llvm/Support/Casting.h"
 #include "llvm/IR/User.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
 #include "gtest/gtest.h"
 #include <cstdlib>

 namespace llvm {
 // Used to test illegal cast. If a cast doesn't match any of the "real" ones,
 // it will match this one.
 struct IllegalCast;
 template <typename T> IllegalCast *cast(...) { return nullptr; }

 // set up two example classes
 // with conversion facility
 //
 struct bar {
   bar() {}
   struct foo *baz();
   struct foo *caz();
   struct foo *daz();
   struct foo *naz();

 private:
   bar(const bar &);
 };
 struct foo {
   foo(const bar &) {}
   void ext() const;
 };

 struct base {
   virtual ~base() {}
 };

 struct derived : public base {
   static bool classof(const base *B) { return true; }
 };

 template <> struct isa_impl<foo, bar> {
   static inline bool doit(const bar &Val) {
     dbgs() << "Classof: " << &Val << "\n";
     return true;
   }
 };

 // Note for the future - please don't do this. isa_impl is an internal template
 // for the implementation of `isa` and should not be exposed this way.
 // Completely unrelated types *should* result in compiler errors if you try to
 // cast between them.
 template <typename T> struct isa_impl<foo, T> {
   static inline bool doit(const T &Val) { return false; }
 };

 foo *bar::baz() { return cast<foo>(this); }

 foo *bar::caz() { return cast_or_null<foo>(this); }

 foo *bar::daz() { return dyn_cast<foo>(this); }

 foo *bar::naz() { return dyn_cast_or_null<foo>(this); }

 bar *fub();

 template <> struct simplify_type<foo> {
   typedef int SimpleType;
   static SimpleType getSimplifiedValue(foo &Val) { return 0; }
 };

 struct T1 {};

 struct T2 {
   T2(const T1 &x) {}
   static bool classof(const T1 *x) { return true; }
 };

 template <> struct CastInfo<T2, T1> : public OptionalValueCast<T2, T1> {};

 struct T3 {
   T3(const T1 *x) : hasValue(x != nullptr) {}

   static bool classof(const T1 *x) { return true; }
   bool hasValue = false;
 };

 // T3 is convertible from a pointer to T1.
 template <> struct CastInfo<T3, T1 *> : public ValueFromPointerCast<T3, T1> {};

 struct T4 {
   T4() : hasValue(false) {}
   T4(const T3 &x) : hasValue(true) {}

   static bool classof(const T3 *x) { return true; }
   bool hasValue = false;
 };

 template <> struct ValueIsPresent<T3> {
   using UnwrappedType = T3;
   static inline bool isPresent(const T3 &t) { return t.hasValue; }
   static inline const T3 &unwrapValue(const T3 &t) { return t; }
 };

 template <> struct CastInfo<T4, T3> {
   using CastResultType = T4;
   static inline CastResultType doCast(const T3 &t) { return T4(t); }
   static inline CastResultType castFailed() { return CastResultType(); }
   static inline CastResultType doCastIfPossible(const T3 &f) {
     return doCast(f);
   }
 };

 } // namespace llvm

 using namespace llvm;

 // Test the peculiar behavior of Use in simplify_type.
 static_assert(std::is_same_v<simplify_type<Use>::SimpleType, Value *>,
               "Use doesn't simplify correctly!");
 static_assert(std::is_same_v<simplify_type<Use *>::SimpleType, Value *>,
               "Use doesn't simplify correctly!");

 // Test that a regular class behaves as expected.
 static_assert(std::is_same_v<simplify_type<foo>::SimpleType, int>,
               "Unexpected simplify_type result!");
 static_assert(std::is_same_v<simplify_type<foo *>::SimpleType, foo *>,
               "Unexpected simplify_type result!");

 namespace {

 const foo *null_foo = nullptr;

 bar B;
 extern bar &B1;
 bar &B1 = B;
 extern const bar *B2;
 // test various configurations of const
 const bar &B3 = B1;
 const bar *const B4 = B2;

 TEST(CastingTest, isa) {
   EXPECT_TRUE(isa<foo>(B1));
   EXPECT_TRUE(isa<foo>(B2));
   EXPECT_TRUE(isa<foo>(B3));
   EXPECT_TRUE(isa<foo>(B4));
 }

 TEST(CastingTest, isa_and_nonnull) {
   EXPECT_TRUE(isa_and_nonnull<foo>(B2));
   EXPECT_TRUE(isa_and_nonnull<foo>(B4));
   EXPECT_FALSE(isa_and_nonnull<foo>(fub()));
 }

 TEST(CastingTest, cast) {
   foo &F1 = cast<foo>(B1);
   EXPECT_NE(&F1, null_foo);
   const foo *F3 = cast<foo>(B2);
   EXPECT_NE(F3, null_foo);
   const foo *F4 = cast<foo>(B2);
   EXPECT_NE(F4, null_foo);
   const foo &F5 = cast<foo>(B3);
   EXPECT_NE(&F5, null_foo);
   const foo *F6 = cast<foo>(B4);
   EXPECT_NE(F6, null_foo);
   // Can't pass null pointer to cast<>.
   // foo *F7 = cast<foo>(fub());
   // EXPECT_EQ(F7, null_foo);
   foo *F8 = B1.baz();
   EXPECT_NE(F8, null_foo);

   std::unique_ptr<const bar> BP(B2);
   auto FP = cast<foo>(std::move(BP));
   static_assert(std::is_same_v<std::unique_ptr<const foo>, decltype(FP)>,
                 "Incorrect deduced return type!");
   EXPECT_NE(FP.get(), null_foo);
   FP.release();
 }

 TEST(CastingTest, cast_or_null) {
   const foo *F11 = cast_or_null<foo>(B2);
   EXPECT_NE(F11, null_foo);
   const foo *F12 = cast_or_null<foo>(B2);
   EXPECT_NE(F12, null_foo);
   const foo *F13 = cast_or_null<foo>(B4);
   EXPECT_NE(F13, null_foo);
   const foo *F14 = cast_or_null<foo>(fub()); // Shouldn't print.
   EXPECT_EQ(F14, null_foo);
   foo *F15 = B1.caz();
   EXPECT_NE(F15, null_foo);

   std::unique_ptr<const bar> BP(fub());
   auto FP = cast_or_null<foo>(std::move(BP));
   EXPECT_EQ(FP.get(), null_foo);
 }

 TEST(CastingTest, dyn_cast) {
   const foo *F1 = dyn_cast<foo>(B2);
   EXPECT_NE(F1, null_foo);
   const foo *F2 = dyn_cast<foo>(B2);
   EXPECT_NE(F2, null_foo);
   const foo *F3 = dyn_cast<foo>(B4);
   EXPECT_NE(F3, null_foo);
   // Can't pass null pointer to dyn_cast<>.
   // foo *F4 = dyn_cast<foo>(fub());
   // EXPECT_EQ(F4, null_foo);
   foo *F5 = B1.daz();
   EXPECT_NE(F5, null_foo);
 }

 // All these tests forward to dyn_cast_if_present, so they also provde an
 // effective test for its use cases.
 TEST(CastingTest, dyn_cast_or_null) {
   const foo *F1 = dyn_cast_or_null<foo>(B2);
   EXPECT_NE(F1, null_foo);
   const foo *F2 = dyn_cast_or_null<foo>(B2);
   EXPECT_NE(F2, null_foo);
   const foo *F3 = dyn_cast_or_null<foo>(B4);
   EXPECT_NE(F3, null_foo);
   foo *F4 = dyn_cast_or_null<foo>(fub());
   EXPECT_EQ(F4, null_foo);
   foo *F5 = B1.naz();
   EXPECT_NE(F5, null_foo);
   // dyn_cast_if_present should have exactly the same behavior as
   // dyn_cast_or_null.
   const foo *F6 = dyn_cast_if_present<foo>(B2);
   EXPECT_EQ(F6, F2);
 }

 TEST(CastingTest, dyn_cast_value_types) {
   T1 t1;
   std::optional<T2> t2 = dyn_cast<T2>(t1);
   EXPECT_TRUE(t2);

   T2 *t2ptr = dyn_cast<T2>(&t1);
   EXPECT_TRUE(t2ptr != nullptr);

   T3 t3 = dyn_cast<T3>(&t1);
   EXPECT_TRUE(t3.hasValue);
 }

 TEST(CastingTest, dyn_cast_if_present) {
   std::optional<T1> empty{};
   std::optional<T2> F1 = dyn_cast_if_present<T2>(empty);
   EXPECT_FALSE(F1.has_value());

   T1 t1;
   std::optional<T2> F2 = dyn_cast_if_present<T2>(t1);
   EXPECT_TRUE(F2.has_value());

   T1 *t1Null = nullptr;

   // T3 should have hasValue == false because t1Null is nullptr.
   T3 t3 = dyn_cast_if_present<T3>(t1Null);
   EXPECT_FALSE(t3.hasValue);

   // Now because of that, T4 should receive the castFailed implementation of its
   // FallibleCastTraits, which default-constructs a T4, which has no value.
   T4 t4 = dyn_cast_if_present<T4>(t3);
   EXPECT_FALSE(t4.hasValue);
 }

 std::unique_ptr<derived> newd() { return std::make_unique<derived>(); }
 std::unique_ptr<base> newb() { return std::make_unique<derived>(); }

 TEST(CastingTest, unique_dyn_cast) {
   derived *OrigD = nullptr;
   auto D = std::make_unique<derived>();
   OrigD = D.get();

   // Converting from D to itself is valid, it should return a new unique_ptr
   // and the old one should become nullptr.
   auto NewD = unique_dyn_cast<derived>(D);
   ASSERT_EQ(OrigD, NewD.get());
   ASSERT_EQ(nullptr, D);

   // Converting from D to B is valid, B should have a value and D should be
   // nullptr.
   auto B = unique_dyn_cast<base>(NewD);
   ASSERT_EQ(OrigD, B.get());
   ASSERT_EQ(nullptr, NewD);

   // Converting from B to itself is valid, it should return a new unique_ptr
   // and the old one should become nullptr.
   auto NewB = unique_dyn_cast<base>(B);
   ASSERT_EQ(OrigD, NewB.get());
   ASSERT_EQ(nullptr, B);

   // Converting from B to D is valid, D should have a value and B should be
   // nullptr;
   D = unique_dyn_cast<derived>(NewB);
   ASSERT_EQ(OrigD, D.get());
   ASSERT_EQ(nullptr, NewB);

   // This is a very contrived test, casting between completely unrelated types
   // should generally fail to compile. See the classof shenanigans we have in
   // the definition of `foo` above.
   auto F = unique_dyn_cast<foo>(D);
   ASSERT_EQ(nullptr, F);
   ASSERT_EQ(OrigD, D.get());

   // All of the above should also hold for temporaries.
   auto D2 = unique_dyn_cast<derived>(newd());
   EXPECT_NE(nullptr, D2);

   auto B2 = unique_dyn_cast<derived>(newb());
   EXPECT_NE(nullptr, B2);

   auto B3 = unique_dyn_cast<base>(newb());
   EXPECT_NE(nullptr, B3);

   // This is a very contrived test, casting between completely unrelated types
   // should generally fail to compile. See the classof shenanigans we have in
   // the definition of `foo` above.
   auto F2 = unique_dyn_cast<foo>(newb());
   EXPECT_EQ(nullptr, F2);
 }

 // These lines are errors...
 // foo *F20 = cast<foo>(B2);  // Yields const foo*
 // foo &F21 = cast<foo>(B3);  // Yields const foo&
 // foo *F22 = cast<foo>(B4);  // Yields const foo*
 // foo &F23 = cast_or_null<foo>(B1);
 // const foo &F24 = cast_or_null<foo>(B3);

 const bar *B2 = &B;
 } // anonymous namespace

 bar *llvm::fub() { return nullptr; }

 namespace {
 namespace inferred_upcasting {
 // This test case verifies correct behavior of inferred upcasts when the
 // types are statically known to be OK to upcast. This is the case when,
 // for example, Derived inherits from Base, and we do `isa<Base>(Derived)`.

 // Note: This test will actually fail to compile without inferred
 // upcasting.

 class Base {
 public:
   // No classof. We are testing that the upcast is inferred.
   Base() {}
 };

 class Derived : public Base {
 public:
   Derived() {}
 };

 // Even with no explicit classof() in Base, we should still be able to cast
 // Derived to its base class.
 TEST(CastingTest, UpcastIsInferred) {
   Derived D;
   EXPECT_TRUE(isa<Base>(D));
   Base *BP = dyn_cast<Base>(&D);
   EXPECT_NE(BP, nullptr);
 }

 // This test verifies that the inferred upcast takes precedence over an
 // explicitly written one. This is important because it verifies that the
 // dynamic check gets optimized away.
 class UseInferredUpcast {
 public:
   int Dummy;
   static bool classof(const UseInferredUpcast *) { return false; }
 };

 TEST(CastingTest, InferredUpcastTakesPrecedence) {
   UseInferredUpcast UIU;
   // Since the explicit classof() returns false, this will fail if the
   // explicit one is used.
   EXPECT_TRUE(isa<UseInferredUpcast>(&UIU));
 }

 } // end namespace inferred_upcasting
 } // end anonymous namespace

 namespace {
 namespace pointer_wrappers {

 struct Base {
   bool IsDerived;
   Base(bool IsDerived = false) : IsDerived(IsDerived) {}
 };

 struct Derived : Base {
   Derived() : Base(true) {}
   static bool classof(const Base *B) { return B->IsDerived; }
 };

 class PTy {
   Base *B;

 public:
   PTy(Base *B) : B(B) {}
   explicit operator bool() const { return get(); }
   Base *get() const { return B; }
 };

 } // end namespace pointer_wrappers
 } // end namespace

 namespace llvm {

 template <> struct ValueIsPresent<pointer_wrappers::PTy> {
   using UnwrappedType = pointer_wrappers::PTy;
   static inline bool isPresent(const pointer_wrappers::PTy &P) {
     return P.get() != nullptr;
   }
   static UnwrappedType &unwrapValue(pointer_wrappers::PTy &P) { return P; }
 };

 template <> struct ValueIsPresent<const pointer_wrappers::PTy> {
   using UnwrappedType = pointer_wrappers::PTy;
   static inline bool isPresent(const pointer_wrappers::PTy &P) {
     return P.get() != nullptr;
   }

   static UnwrappedType &unwrapValue(const pointer_wrappers::PTy &P) {
     return const_cast<UnwrappedType &>(P);
   }
 };

 template <> struct simplify_type<pointer_wrappers::PTy> {
   typedef pointer_wrappers::Base *SimpleType;
   static SimpleType getSimplifiedValue(pointer_wrappers::PTy &P) {
     return P.get();
   }
 };
 template <> struct simplify_type<const pointer_wrappers::PTy> {
   typedef pointer_wrappers::Base *SimpleType;
   static SimpleType getSimplifiedValue(const pointer_wrappers::PTy &P) {
     return P.get();
   }
 };

 } // end namespace llvm

 namespace {
 namespace pointer_wrappers {

 // Some objects.
 pointer_wrappers::Base B;
 pointer_wrappers::Derived D;

 // Mutable "smart" pointers.
 pointer_wrappers::PTy MN(nullptr);
 pointer_wrappers::PTy MB(&B);
 pointer_wrappers::PTy MD(&D);

 // Const "smart" pointers.
 const pointer_wrappers::PTy CN(nullptr);
 const pointer_wrappers::PTy CB(&B);
 const pointer_wrappers::PTy CD(&D);

 TEST(CastingTest, smart_isa) {
   EXPECT_TRUE(!isa<pointer_wrappers::Derived>(MB));
   EXPECT_TRUE(!isa<pointer_wrappers::Derived>(CB));
   EXPECT_TRUE(isa<pointer_wrappers::Derived>(MD));
   EXPECT_TRUE(isa<pointer_wrappers::Derived>(CD));
 }

 TEST(CastingTest, smart_cast) {
   EXPECT_EQ(cast<pointer_wrappers::Derived>(MD), &D);
   EXPECT_EQ(cast<pointer_wrappers::Derived>(CD), &D);
 }

 TEST(CastingTest, smart_cast_or_null) {
   EXPECT_EQ(cast_or_null<pointer_wrappers::Derived>(MN), nullptr);
   EXPECT_EQ(cast_or_null<pointer_wrappers::Derived>(CN), nullptr);
   EXPECT_EQ(cast_or_null<pointer_wrappers::Derived>(MD), &D);
   EXPECT_EQ(cast_or_null<pointer_wrappers::Derived>(CD), &D);
 }

 TEST(CastingTest, smart_dyn_cast) {
   EXPECT_EQ(dyn_cast<pointer_wrappers::Derived>(MB), nullptr);
   EXPECT_EQ(dyn_cast<pointer_wrappers::Derived>(CB), nullptr);
   EXPECT_EQ(dyn_cast<pointer_wrappers::Derived>(MD), &D);
   EXPECT_EQ(dyn_cast<pointer_wrappers::Derived>(CD), &D);
 }

 TEST(CastingTest, smart_dyn_cast_or_null) {
   EXPECT_EQ(dyn_cast_or_null<pointer_wrappers::Derived>(MN), nullptr);
   EXPECT_EQ(dyn_cast_or_null<pointer_wrappers::Derived>(CN), nullptr);
   EXPECT_EQ(dyn_cast_or_null<pointer_wrappers::Derived>(MB), nullptr);
   EXPECT_EQ(dyn_cast_or_null<pointer_wrappers::Derived>(CB), nullptr);
   EXPECT_EQ(dyn_cast_or_null<pointer_wrappers::Derived>(MD), &D);
   EXPECT_EQ(dyn_cast_or_null<pointer_wrappers::Derived>(CD), &D);
 }

 } // end namespace pointer_wrappers

 #ifndef NDEBUG
 namespace assertion_checks {
 struct Base {
   virtual ~Base() {}
 };

 struct Derived : public Base {
   static bool classof(const Base *B) { return false; }
 };

 TEST(CastingTest, assertion_check_const_ref) {
   const Base B;
   EXPECT_DEATH((void)cast<Derived>(B), "argument of incompatible type")
       << "Invalid cast of const ref did not cause an abort()";
 }

 TEST(CastingTest, assertion_check_ref) {
   Base B;
   EXPECT_DEATH((void)cast<Derived>(B), "argument of incompatible type")
       << "Invalid cast of const ref did not cause an abort()";
 }

 TEST(CastingTest, assertion_check_ptr) {
   Base B;
   EXPECT_DEATH((void)cast<Derived>(&B), "argument of incompatible type")
       << "Invalid cast of const ref did not cause an abort()";
 }

 TEST(CastingTest, assertion_check_unique_ptr) {
   auto B = std::make_unique<Base>();
   EXPECT_DEATH((void)cast<Derived>(std::move(B)),
                "argument of incompatible type")
       << "Invalid cast of const ref did not cause an abort()";
 }

 } // end namespace assertion_checks
 #endif
 } // end namespace
	//===---------- llvm/unittest/Support/Casting.cpp - Casting tests ---------===//
	//
	// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
	// See https://llvm.org/LICENSE.txt for license information.
	// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
	//
	//===----------------------------------------------------------------------===//

	#include "llvm/Support/Casting.h"
	#include "llvm/IR/User.h"
	#include "llvm/Support/Debug.h"
	#include "llvm/Support/raw_ostream.h"
	#include "gtest/gtest.h"
	#include <cstdlib>

	namespace llvm {
	// Used to test illegal cast. If a cast doesn't match any of the "real" ones,
	// it will match this one.
	struct IllegalCast;
	template <typename T> IllegalCast *cast(...) { return nullptr; }

	// set up two example classes
	// with conversion facility
	//
	struct bar {
	bar() {}
	struct foo *baz();
	struct foo *caz();
	struct foo *daz();
	struct foo *naz();

	private:
	bar(const bar &);
	};
	struct foo {
	foo(const bar &) {}
	void ext() const;
	};

	struct base {
	virtual ~base() {}
	};

	struct derived : public base {
	static bool classof(const base *B) { return true; }
	};

	template <> struct isa_impl<foo, bar> {
	static inline bool doit(const bar &Val) {
	dbgs() << "Classof: " << &Val << "\n";
	return true;
	}
	};

	// Note for the future - please don't do this. isa_impl is an internal template
	// for the implementation of `isa` and should not be exposed this way.
	// Completely unrelated types should result in compiler errors if you try to
	// cast between them.
	template <typename T> struct isa_impl<foo, T> {
	static inline bool doit(const T &Val) { return false; }
	};

	foo *bar::baz() { return cast<foo>(this); }

	foo *bar::caz() { return cast_or_null<foo>(this); }

	foo *bar::daz() { return dyn_cast<foo>(this); }

	foo *bar::naz() { return dyn_cast_or_null<foo>(this); }

	bar *fub();

	template <> struct simplify_type<foo> {
	typedef int SimpleType;
	static SimpleType getSimplifiedValue(foo &Val) { return 0; }
	};

	struct T1 {};

	struct T2 {
	T2(const T1 &x) {}
	static bool classof(const T1 *x) { return true; }
	};

	template <> struct CastInfo<T2, T1> : public OptionalValueCast<T2, T1> {};

	struct T3 {
	T3(const T1 *x) : hasValue(x != nullptr) {}

	static bool classof(const T1 *x) { return true; }
	bool hasValue = false;
	};

	// T3 is convertible from a pointer to T1.
	template <> struct CastInfo<T3, T1 *> : public ValueFromPointerCast<T3, T1> {};

	struct T4 {
	T4() : hasValue(false) {}
	T4(const T3 &x) : hasValue(true) {}

	static bool classof(const T3 *x) { return true; }
	bool hasValue = false;
	};

	template <> struct ValueIsPresent<T3> {
	using UnwrappedType = T3;
	static inline bool isPresent(const T3 &t) { return t.hasValue; }
	static inline const T3 &unwrapValue(const T3 &t) { return t; }
	};

	template <> struct CastInfo<T4, T3> {
	using CastResultType = T4;
	static inline CastResultType doCast(const T3 &t) { return T4(t); }
	static inline CastResultType castFailed() { return CastResultType(); }
	static inline CastResultType doCastIfPossible(const T3 &f) {
	return doCast(f);
	}
	};

	} // namespace llvm

	using namespace llvm;

	// Test the peculiar behavior of Use in simplify_type.
	static_assert(std::is_same_v<simplify_type<Use>::SimpleType, Value *>,
	"Use doesn't simplify correctly!");
	static_assert(std::is_same_v<simplify_type<Use >::SimpleType, Value >,
	"Use doesn't simplify correctly!");

	// Test that a regular class behaves as expected.
	static_assert(std::is_same_v<simplify_type<foo>::SimpleType, int>,
	"Unexpected simplify_type result!");
	static_assert(std::is_same_v<simplify_type<foo >::SimpleType, foo >,
	"Unexpected simplify_type result!");

	namespace {

	const foo *null_foo = nullptr;

	bar B;
	extern bar &B1;
	bar &B1 = B;
	extern const bar *B2;
	// test various configurations of const
	const bar &B3 = B1;
	const bar *const B4 = B2;

	TEST(CastingTest, isa) {
	EXPECT_TRUE(isa<foo>(B1));
	EXPECT_TRUE(isa<foo>(B2));
	EXPECT_TRUE(isa<foo>(B3));
	EXPECT_TRUE(isa<foo>(B4));
	}

	TEST(CastingTest, isa_and_nonnull) {
	EXPECT_TRUE(isa_and_nonnull<foo>(B2));
	EXPECT_TRUE(isa_and_nonnull<foo>(B4));
	EXPECT_FALSE(isa_and_nonnull<foo>(fub()));
	}

	TEST(CastingTest, cast) {
	foo &F1 = cast<foo>(B1);
	EXPECT_NE(&F1, null_foo);
	const foo *F3 = cast<foo>(B2);
	EXPECT_NE(F3, null_foo);
	const foo *F4 = cast<foo>(B2);
	EXPECT_NE(F4, null_foo);
	const foo &F5 = cast<foo>(B3);
	EXPECT_NE(&F5, null_foo);
	const foo *F6 = cast<foo>(B4);
	EXPECT_NE(F6, null_foo);
	// Can't pass null pointer to cast<>.
	// foo *F7 = cast<foo>(fub());
	// EXPECT_EQ(F7, null_foo);
	foo *F8 = B1.baz();
	EXPECT_NE(F8, null_foo);

	std::unique_ptr<const bar> BP(B2);
	auto FP = cast<foo>(std::move(BP));
	static_assert(std::is_same_v<std::unique_ptr<const foo>, decltype(FP)>,
	"Incorrect deduced return type!");
	EXPECT_NE(FP.get(), null_foo);
	FP.release();
	}

	TEST(CastingTest, cast_or_null) {
	const foo *F11 = cast_or_null<foo>(B2);
	EXPECT_NE(F11, null_foo);
	const foo *F12 = cast_or_null<foo>(B2);
	EXPECT_NE(F12, null_foo);
	const foo *F13 = cast_or_null<foo>(B4);
	EXPECT_NE(F13, null_foo);
	const foo *F14 = cast_or_null<foo>(fub()); // Shouldn't print.
	EXPECT_EQ(F14, null_foo);
	foo *F15 = B1.caz();
	EXPECT_NE(F15, null_foo);

	std::unique_ptr<const bar> BP(fub());
	auto FP = cast_or_null<foo>(std::move(BP));
	EXPECT_EQ(FP.get(), null_foo);
	}

	TEST(CastingTest, dyn_cast) {
	const foo *F1 = dyn_cast<foo>(B2);
	EXPECT_NE(F1, null_foo);
	const foo *F2 = dyn_cast<foo>(B2);
	EXPECT_NE(F2, null_foo);
	const foo *F3 = dyn_cast<foo>(B4);
	EXPECT_NE(F3, null_foo);
	// Can't pass null pointer to dyn_cast<>.
	// foo *F4 = dyn_cast<foo>(fub());
	// EXPECT_EQ(F4, null_foo);
	foo *F5 = B1.daz();
	EXPECT_NE(F5, null_foo);
	}

	// All these tests forward to dyn_cast_if_present, so they also provde an
	// effective test for its use cases.
	TEST(CastingTest, dyn_cast_or_null) {
	const foo *F1 = dyn_cast_or_null<foo>(B2);
	EXPECT_NE(F1, null_foo);
	const foo *F2 = dyn_cast_or_null<foo>(B2);
	EXPECT_NE(F2, null_foo);
	const foo *F3 = dyn_cast_or_null<foo>(B4);
	EXPECT_NE(F3, null_foo);
	foo *F4 = dyn_cast_or_null<foo>(fub());
	EXPECT_EQ(F4, null_foo);
	foo *F5 = B1.naz();
	EXPECT_NE(F5, null_foo);
	// dyn_cast_if_present should have exactly the same behavior as
	// dyn_cast_or_null.
	const foo *F6 = dyn_cast_if_present<foo>(B2);
	EXPECT_EQ(F6, F2);
	}

	TEST(CastingTest, dyn_cast_value_types) {
	T1 t1;
	std::optional<T2> t2 = dyn_cast<T2>(t1);
	EXPECT_TRUE(t2);

	T2 *t2ptr = dyn_cast<T2>(&t1);
	EXPECT_TRUE(t2ptr != nullptr);

	T3 t3 = dyn_cast<T3>(&t1);
	EXPECT_TRUE(t3.hasValue);
	}

	TEST(CastingTest, dyn_cast_if_present) {
	std::optional<T1> empty{};
	std::optional<T2> F1 = dyn_cast_if_present<T2>(empty);
	EXPECT_FALSE(F1.has_value());

	T1 t1;
	std::optional<T2> F2 = dyn_cast_if_present<T2>(t1);
	EXPECT_TRUE(F2.has_value());

	T1 *t1Null = nullptr;

	// T3 should have hasValue == false because t1Null is nullptr.
	T3 t3 = dyn_cast_if_present<T3>(t1Null);
	EXPECT_FALSE(t3.hasValue);

	// Now because of that, T4 should receive the castFailed implementation of its
	// FallibleCastTraits, which default-constructs a T4, which has no value.
	T4 t4 = dyn_cast_if_present<T4>(t3);
	EXPECT_FALSE(t4.hasValue);
	}

	std::unique_ptr<derived> newd() { return std::make_unique<derived>(); }
	std::unique_ptr<base> newb() { return std::make_unique<derived>(); }

	TEST(CastingTest, unique_dyn_cast) {
	derived *OrigD = nullptr;
	auto D = std::make_unique<derived>();
	OrigD = D.get();

	// Converting from D to itself is valid, it should return a new unique_ptr
	// and the old one should become nullptr.
	auto NewD = unique_dyn_cast<derived>(D);
	ASSERT_EQ(OrigD, NewD.get());
	ASSERT_EQ(nullptr, D);

	// Converting from D to B is valid, B should have a value and D should be
	// nullptr.
	auto B = unique_dyn_cast<base>(NewD);
	ASSERT_EQ(OrigD, B.get());
	ASSERT_EQ(nullptr, NewD);

	// Converting from B to itself is valid, it should return a new unique_ptr
	// and the old one should become nullptr.
	auto NewB = unique_dyn_cast<base>(B);
	ASSERT_EQ(OrigD, NewB.get());
	ASSERT_EQ(nullptr, B);

	// Converting from B to D is valid, D should have a value and B should be
	// nullptr;
	D = unique_dyn_cast<derived>(NewB);
	ASSERT_EQ(OrigD, D.get());
	ASSERT_EQ(nullptr, NewB);

	// This is a very contrived test, casting between completely unrelated types
	// should generally fail to compile. See the classof shenanigans we have in
	// the definition of `foo` above.
	auto F = unique_dyn_cast<foo>(D);
	ASSERT_EQ(nullptr, F);
	ASSERT_EQ(OrigD, D.get());

	// All of the above should also hold for temporaries.
	auto D2 = unique_dyn_cast<derived>(newd());
	EXPECT_NE(nullptr, D2);

	auto B2 = unique_dyn_cast<derived>(newb());
	EXPECT_NE(nullptr, B2);

	auto B3 = unique_dyn_cast<base>(newb());
	EXPECT_NE(nullptr, B3);

	// This is a very contrived test, casting between completely unrelated types
	// should generally fail to compile. See the classof shenanigans we have in
	// the definition of `foo` above.
	auto F2 = unique_dyn_cast<foo>(newb());
	EXPECT_EQ(nullptr, F2);
	}

	// These lines are errors...
	// foo F20 = cast<foo>(B2); // Yields const foo
	// foo &F21 = cast<foo>(B3); // Yields const foo&
	// foo F22 = cast<foo>(B4); // Yields const foo
	// foo &F23 = cast_or_null<foo>(B1);
	// const foo &F24 = cast_or_null<foo>(B3);

	const bar *B2 = &B;
	} // anonymous namespace

	bar *llvm::fub() { return nullptr; }

	namespace {
	namespace inferred_upcasting {
	// This test case verifies correct behavior of inferred upcasts when the
	// types are statically known to be OK to upcast. This is the case when,
	// for example, Derived inherits from Base, and we do `isa<Base>(Derived)`.

	// Note: This test will actually fail to compile without inferred
	// upcasting.

	class Base {
	public:
	// No classof. We are testing that the upcast is inferred.
	Base() {}
	};

	class Derived : public Base {
	public:
	Derived() {}
	};

	// Even with no explicit classof() in Base, we should still be able to cast
	// Derived to its base class.
	TEST(CastingTest, UpcastIsInferred) {
	Derived D;
	EXPECT_TRUE(isa<Base>(D));
	Base *BP = dyn_cast<Base>(&D);
	EXPECT_NE(BP, nullptr);
	}

	// This test verifies that the inferred upcast takes precedence over an
	// explicitly written one. This is important because it verifies that the
	// dynamic check gets optimized away.
	class UseInferredUpcast {
	public:
	int Dummy;
	static bool classof(const UseInferredUpcast *) { return false; }
	};

	TEST(CastingTest, InferredUpcastTakesPrecedence) {
	UseInferredUpcast UIU;
	// Since the explicit classof() returns false, this will fail if the
	// explicit one is used.
	EXPECT_TRUE(isa<UseInferredUpcast>(&UIU));
	}

	} // end namespace inferred_upcasting
	} // end anonymous namespace

	namespace {
	namespace pointer_wrappers {

	struct Base {
	bool IsDerived;
	Base(bool IsDerived = false) : IsDerived(IsDerived) {}
	};

	struct Derived : Base {
	Derived() : Base(true) {}
	static bool classof(const Base *B) { return B->IsDerived; }
	};

	class PTy {
	Base *B;

	public:
	PTy(Base *B) : B(B) {}
	explicit operator bool() const { return get(); }
	Base *get() const { return B; }
	};

	} // end namespace pointer_wrappers
	} // end namespace

	namespace llvm {

	template <> struct ValueIsPresent<pointer_wrappers::PTy> {
	using UnwrappedType = pointer_wrappers::PTy;
	static inline bool isPresent(const pointer_wrappers::PTy &P) {
	return P.get() != nullptr;
	}
	static UnwrappedType &unwrapValue(pointer_wrappers::PTy &P) { return P; }
	};

	template <> struct ValueIsPresent<const pointer_wrappers::PTy> {
	using UnwrappedType = pointer_wrappers::PTy;
	static inline bool isPresent(const pointer_wrappers::PTy &P) {
	return P.get() != nullptr;
	}

	static UnwrappedType &unwrapValue(const pointer_wrappers::PTy &P) {
	return const_cast<UnwrappedType &>(P);
	}
	};

	template <> struct simplify_type<pointer_wrappers::PTy> {
	typedef pointer_wrappers::Base *SimpleType;
	static SimpleType getSimplifiedValue(pointer_wrappers::PTy &P) {
	return P.get();
	}
	};
	template <> struct simplify_type<const pointer_wrappers::PTy> {
	typedef pointer_wrappers::Base *SimpleType;
	static SimpleType getSimplifiedValue(const pointer_wrappers::PTy &P) {
	return P.get();
	}
	};

	} // end namespace llvm

	namespace {
	namespace pointer_wrappers {

	// Some objects.
	pointer_wrappers::Base B;
	pointer_wrappers::Derived D;

	// Mutable "smart" pointers.
	pointer_wrappers::PTy MN(nullptr);
	pointer_wrappers::PTy MB(&B);
	pointer_wrappers::PTy MD(&D);

	// Const "smart" pointers.
	const pointer_wrappers::PTy CN(nullptr);
	const pointer_wrappers::PTy CB(&B);
	const pointer_wrappers::PTy CD(&D);

	TEST(CastingTest, smart_isa) {
	EXPECT_TRUE(!isa<pointer_wrappers::Derived>(MB));
	EXPECT_TRUE(!isa<pointer_wrappers::Derived>(CB));
	EXPECT_TRUE(isa<pointer_wrappers::Derived>(MD));
	EXPECT_TRUE(isa<pointer_wrappers::Derived>(CD));
	}

	TEST(CastingTest, smart_cast) {
	EXPECT_EQ(cast<pointer_wrappers::Derived>(MD), &D);
	EXPECT_EQ(cast<pointer_wrappers::Derived>(CD), &D);
	}

	TEST(CastingTest, smart_cast_or_null) {
	EXPECT_EQ(cast_or_null<pointer_wrappers::Derived>(MN), nullptr);
	EXPECT_EQ(cast_or_null<pointer_wrappers::Derived>(CN), nullptr);
	EXPECT_EQ(cast_or_null<pointer_wrappers::Derived>(MD), &D);
	EXPECT_EQ(cast_or_null<pointer_wrappers::Derived>(CD), &D);
	}

	TEST(CastingTest, smart_dyn_cast) {
	EXPECT_EQ(dyn_cast<pointer_wrappers::Derived>(MB), nullptr);
	EXPECT_EQ(dyn_cast<pointer_wrappers::Derived>(CB), nullptr);
	EXPECT_EQ(dyn_cast<pointer_wrappers::Derived>(MD), &D);
	EXPECT_EQ(dyn_cast<pointer_wrappers::Derived>(CD), &D);
	}

	TEST(CastingTest, smart_dyn_cast_or_null) {
	EXPECT_EQ(dyn_cast_or_null<pointer_wrappers::Derived>(MN), nullptr);
	EXPECT_EQ(dyn_cast_or_null<pointer_wrappers::Derived>(CN), nullptr);
	EXPECT_EQ(dyn_cast_or_null<pointer_wrappers::Derived>(MB), nullptr);
	EXPECT_EQ(dyn_cast_or_null<pointer_wrappers::Derived>(CB), nullptr);
	EXPECT_EQ(dyn_cast_or_null<pointer_wrappers::Derived>(MD), &D);
	EXPECT_EQ(dyn_cast_or_null<pointer_wrappers::Derived>(CD), &D);
	}

	} // end namespace pointer_wrappers

	#ifndef NDEBUG
	namespace assertion_checks {
	struct Base {
	virtual ~Base() {}
	};

	struct Derived : public Base {
	static bool classof(const Base *B) { return false; }
	};

	TEST(CastingTest, assertion_check_const_ref) {
	const Base B;
	EXPECT_DEATH((void)cast<Derived>(B), "argument of incompatible type")
	<< "Invalid cast of const ref did not cause an abort()";
	}

	TEST(CastingTest, assertion_check_ref) {
	Base B;
	EXPECT_DEATH((void)cast<Derived>(B), "argument of incompatible type")
	<< "Invalid cast of const ref did not cause an abort()";
	}

	TEST(CastingTest, assertion_check_ptr) {
	Base B;
	EXPECT_DEATH((void)cast<Derived>(&B), "argument of incompatible type")
	<< "Invalid cast of const ref did not cause an abort()";
	}

	TEST(CastingTest, assertion_check_unique_ptr) {
	auto B = std::make_unique<Base>();
	EXPECT_DEATH((void)cast<Derived>(std::move(B)),
	"argument of incompatible type")
	<< "Invalid cast of const ref did not cause an abort()";
	}

	} // end namespace assertion_checks
	#endif
	} // end namespace