llvm-project/clang/test/SemaTemplate/default-arguments-cxx0x.cpp
Volodymyr Sapsai 4fbaa62b60 [Sema] Prevent InstantiateClass from checking unrelated exception specs.
Sema::InstantiateClass should check only exception specs added during
class instantiation and ignore already present delayed specs. This fixes
a case where we instantiate a class before parsing member initializers,
check exceptions for a different class and fail to find a member
initializer. Which is required for comparing exception specs for
explicitly-defaulted and implicit default constructor. With the fix we
are still checking exception specs but only after member initializers
are present.

Removing errors in crash-unparsed-exception.cpp is acceptable according
to discussion in PR24000 because other compilers accept code in
crash-unparsed-exception.cpp as valid.

rdar://problem/34167492

Reviewers: davide, rsmith

Reviewed By: rsmith

Subscribers: dim, cfe-commits

Differential Revision: https://reviews.llvm.org/D37881

llvm-svn: 313906
2017-09-21 19:54:12 +00:00

117 lines
2.8 KiB
C++

// RUN: %clang_cc1 -fsyntax-only -std=c++11 -verify %s
// expected-no-diagnostics
// Test default template arguments for function templates.
template<typename T = int>
void f0();
template<typename T>
void f0();
void g0() {
f0(); // okay!
}
template<typename T, int N = T::value>
int &f1(T);
float &f1(...);
struct HasValue {
static const int value = 17;
};
void g1() {
float &fr = f1(15);
int &ir = f1(HasValue());
}
namespace PR16689 {
template <typename T1, typename T2> class tuple {
public:
template <typename = T2>
constexpr tuple() {}
};
template <class X, class... Y> struct a : public X {
using X::X;
};
auto x = a<tuple<int, int> >();
}
namespace PR16975 {
template <typename...> struct is {
constexpr operator bool() const { return false; }
};
template <typename... Types>
struct bar {
template <typename T,
bool = is<Types...>()>
bar(T);
};
bar<> foo{0};
struct baz : public bar<> {
using bar::bar;
};
baz data{0};
}
// rdar://23810407
// An IRGen failure due to a symbol collision due to a default argument
// being instantiated twice. Credit goes to Richard Smith for this
// reduction to a -fsyntax-only failure.
namespace rdar23810407 {
// Instantiating the default argument multiple times will produce two
// different lambda types and thus instantiate this function multiple
// times, which will produce conflicting extern variable declarations.
template<typename T> int f(T t) {
extern T rdar23810407_variable;
return 0;
}
template<typename T> int g(int a = f([] {}));
void test() {
g<int>();
g<int>();
}
}
// rdar://problem/24480205
namespace PR13986 {
constexpr unsigned Dynamic = 0;
template <unsigned> class A { template <unsigned = Dynamic> void m_fn1(); };
class Test {
~Test() {}
A<1> m_target;
};
}
// rdar://problem/34167492
// Template B is instantiated during checking if defaulted A copy constructor
// is constexpr. For this we check if S<int> copy constructor is constexpr. And
// for this we check S constructor template with default argument that mentions
// template B. In turn, template instantiation triggers checking defaulted
// members exception spec. The problem is that it checks defaulted members not
// for instantiated class only, but all defaulted members so far. In this case
// we try to check exception spec for A default constructor which requires
// initializer for the field _a. But initializers are added after constexpr
// check so we reject the code because cannot find _a initializer.
namespace rdar34167492 {
template <typename T> struct B { using type = bool; };
template <typename T> struct S {
S() noexcept;
template <typename U, typename B<U>::type = true>
S(const S<U>&) noexcept;
};
class A {
A() noexcept = default;
A(const A&) noexcept = default;
S<int> _a{};
};
}