llvm-project/clang/test/Parser/cxx1z-class-template-argument-deduction.cpp
Aaron Ballman a1879e52e3 Fix crash on invalid code involving late parsed inline methods
When parsing the following construct, we parse it as an erroneous
deduction guide declaration and correctly diagnose the issues with it.

template<class> struct B;
struct A { B() noexcept(false); };

However, we then go on to finish late parsing the declaration and this
expects that what we've parsed is a CXXMethodDecl. A
CXXDeductionGuideDecl is not a CXXMethodDecl (it's a FunctionDecl), and
so we assert on the cast.

This fixes the crash by switching from cast<> to dyn_cast<> and not
setting up a "this" scope when the declaration is not a CXXMethodDecl.

This fixes PR49735.
2021-12-16 07:58:51 -05:00

251 lines
12 KiB
C++

// RUN: %clang_cc1 -std=c++1z -fcxx-exceptions -verify %s
template <typename T> struct A { // expected-note 38{{declared here}}
constexpr A() {}
constexpr A(int) {}
constexpr operator int() { return 0; }
};
A() -> A<int>;
A(int) -> A<int>;
// Make sure we still correctly parse cases where a template can appear without arguments.
namespace template_template_arg {
template<template<typename> typename> struct X {};
template<typename> struct Y {};
X<A> xa;
Y<A> ya; // expected-error {{requires template arguments}}
X<::A> xcca;
Y<::A> ycca; // expected-error {{requires template arguments}}
X<A*> xap; // expected-error {{requires template arguments}}
X<const A> xca; // expected-error {{requires template arguments}}
X<A const> xac; // expected-error {{requires template arguments}}
// FIXME: This should not parse as a template template argument due to the
// trailing attributes.
X<A [[]]> xa_attr;
template<template<typename> typename = A> struct XD {};
template<typename = A> struct YD {}; // expected-error {{requires template arguments}}
template<template<typename> typename = ::A> struct XCCD {};
template<typename = ::A> struct YCCD {}; // expected-error {{requires template arguments}}
// FIXME: replacing the invalid type with 'int' here is horrible
template <A a = A<int>()> class C { }; // expected-error {{requires template arguments}}
template<typename T = A> struct G { }; // expected-error {{requires template arguments}}
}
namespace template_template_arg_pack {
template<template<typename> typename...> struct XP {};
template<typename...> struct YP {};
struct Z { template<typename T> struct Q {}; }; // expected-note 2{{here}}
template<typename T> using ZId = Z;
template<typename ...Ts> struct A {
XP<ZId<Ts>::Q...> xe;
YP<ZId<Ts>::Q...> ye; // expected-error {{requires template arguments}}
XP<ZId<Ts>::Q> xp; // expected-error {{unexpanded parameter pack}}
YP<ZId<Ts>::Q> yp; // expected-error {{requires template arguments}}
};
}
namespace injected_class_name {
template<typename T> struct A {
A(T);
void f(int) { // expected-note {{previous}}
A a = 1;
injected_class_name::A b = 1; // expected-note {{in instantiation of template class 'injected_class_name::A<int>'}}
}
void f(T); // expected-error {{multiple overloads of 'f' instantiate to the same signature 'void (int)}}
};
A<short> ai = 1;
A<double>::A b(1); // expected-error {{constructor name}}
}
struct member {
A a; // expected-error {{requires template arguments}}
A *b; // expected-error {{requires template arguments}}
const A c; // expected-error {{requires template arguments}}
void f() throw (A); // expected-error {{requires template arguments}}
friend A; // expected-error {{requires template arguments; argument deduction not allowed in friend declaration}}
operator A(); // expected-error {{requires template arguments; argument deduction not allowed in conversion function type}}
static A x; // expected-error {{declaration of variable 'x' with deduced type 'A' requires an initializer}}
static constexpr A y = 0;
};
namespace in_typedef {
typedef A *AutoPtr; // expected-error {{requires template arguments; argument deduction not allowed in typedef}}
typedef A (*PFun)(int a); // expected-error{{requires template arguments; argument deduction not allowed in typedef}}
typedef A Fun(int a) -> decltype(a + a); // expected-error{{requires template arguments; argument deduction not allowed in function return type}}
}
namespace stmt {
void g(A a) { // expected-error{{requires template arguments; argument deduction not allowed in function prototype}}
try { }
catch (A &a) { } // expected-error{{requires template arguments; argument deduction not allowed in exception declaration}}
catch (const A a) { } // expected-error{{requires template arguments; argument deduction not allowed in exception declaration}}
try { } catch (A a) { } // expected-error{{requires template arguments; argument deduction not allowed in exception declaration}}
// FIXME: The standard only permits class template argument deduction in a
// simple-declaration or cast. We also permit it in conditions,
// for-range-declarations, member-declarations for static data members, and
// new-expressions, because not doing so would be bizarre.
A local = 0;
static A local_static = 0;
static thread_local A thread_local_static = 0;
if (A a = 0) {}
if (A a = 0; a) {}
switch (A a = 0) {} // expected-warning {{no case matching constant switch condition '0'}}
switch (A a = 0; a) {} // expected-warning {{no case matching constant switch condition '0'}}
for (A a = 0; a; /**/) {}
for (/**/; A a = 0; /**/) {}
while (A a = 0) {}
int arr[3];
for (A a : arr) {}
}
namespace std {
class type_info;
}
}
namespace expr {
template<typename T> struct U {};
void j() {
(void)typeid(A); // expected-error{{requires template arguments; argument deduction not allowed here}}
(void)sizeof(A); // expected-error{{requires template arguments; argument deduction not allowed here}}
(void)__alignof(A); // expected-error{{requires template arguments; argument deduction not allowed here}}
U<A> v; // expected-error {{requires template arguments}}
int n;
(void)dynamic_cast<A&>(n); // expected-error{{requires template arguments; argument deduction not allowed here}}
(void)static_cast<A*>(&n); // expected-error{{requires template arguments; argument deduction not allowed here}}
(void)reinterpret_cast<A*>(&n); // expected-error{{requires template arguments; argument deduction not allowed here}}
(void)const_cast<A>(n); // expected-error{{requires template arguments; argument deduction not allowed here}}
(void)*(A*)(&n); // expected-error{{requires template arguments; argument deduction not allowed here}}
(void)(A)(n); // expected-error{{requires template arguments; argument deduction not allowed here}}
(void)(A){n}; // expected-error{{requires template arguments; argument deduction not allowed here}}
(void)A(n);
(void)A{n};
(void)new A(n);
(void)new A{n};
(void)new A;
}
}
namespace decl {
enum E : A {}; // expected-error{{requires template arguments; argument deduction not allowed here}}
struct F : A {}; // expected-error{{expected class name}}
using B = A; // expected-error{{requires template arguments}}
auto k() -> A; // expected-error{{requires template arguments}}
A a;
A b = 0;
const A c = 0;
A (parens) = 0; // expected-error {{cannot use parentheses when declaring variable with deduced class template specialization type}}
A *p = 0; // expected-error {{cannot form pointer to deduced class template specialization type}}
A &r = *p; // expected-error {{cannot form reference to deduced class template specialization type}}
A arr[3] = 0; // expected-error {{cannot form array of deduced class template specialization type}}
A F::*pm = 0; // expected-error {{cannot form pointer to deduced class template specialization type}}
A (*fp)() = 0; // expected-error {{cannot form function returning deduced class template specialization type}}
A [x, y] = 0; // expected-error {{cannot be declared with type 'A'}} expected-error {{type 'A<int>' decomposes into 0 elements, but 2 names were provided}}
}
namespace typename_specifier {
struct F {};
void e() {
(void) typename ::A(0);
(void) typename ::A{0};
new typename ::A(0);
new typename ::A{0};
typename ::A a = 0;
const typename ::A b = 0;
if (typename ::A a = 0) {}
for (typename ::A a = 0; typename ::A b = 0; /**/) {}
(void)(typename ::A)(0); // expected-error{{requires template arguments; argument deduction not allowed here}}
(void)(typename ::A){0}; // expected-error{{requires template arguments; argument deduction not allowed here}}
}
typename ::A a = 0;
const typename ::A b = 0;
typename ::A (parens) = 0; // expected-error {{cannot use parentheses when declaring variable with deduced class template specialization type}}
typename ::A *p = 0; // expected-error {{cannot form pointer to deduced class template specialization type}}
typename ::A &r = *p; // expected-error {{cannot form reference to deduced class template specialization type}}
typename ::A arr[3] = 0; // expected-error {{cannot form array of deduced class template specialization type}}
typename ::A F::*pm = 0; // expected-error {{cannot form pointer to deduced class template specialization type}}
typename ::A (*fp)() = 0; // expected-error {{cannot form function returning deduced class template specialization type}}
typename ::A [x, y] = 0; // expected-error {{cannot be declared with type 'typename ::A'}} expected-error {{type 'typename ::A<int>' (aka 'A<int>') decomposes into 0}}
struct X { template<typename T> struct A { A(T); }; }; // expected-note 8{{declared here}}
template<typename T> void f() {
(void) typename T::A(0);
(void) typename T::A{0};
new typename T::A(0);
new typename T::A{0};
typename T::A a = 0;
const typename T::A b = 0;
if (typename T::A a = 0) {} // expected-error {{value of type 'typename X::A<int>' (aka 'typename_specifier::X::A<int>') is not contextually convertible to 'bool'}}
for (typename T::A a = 0; typename T::A b = 0; /**/) {} // expected-error {{value of type 'typename X::A<int>' (aka 'typename_specifier::X::A<int>') is not contextually convertible to 'bool'}}
{(void)(typename T::A)(0);} // expected-error{{refers to class template member}}
{(void)(typename T::A){0};} // expected-error{{refers to class template member}}
{typename T::A (parens) = 0;} // expected-error {{refers to class template member in 'typename_specifier::X'; argument deduction not allowed here}}
// expected-warning@-1 {{disambiguated as redundant parentheses around declaration of variable named 'parens'}} expected-note@-1 {{add a variable name}} expected-note@-1{{remove parentheses}} expected-note@-1 {{add enclosing parentheses}}
{typename T::A *p = 0;} // expected-error {{refers to class template member}}
{typename T::A &r = *p;} // expected-error {{refers to class template member}}
{typename T::A arr[3] = 0;} // expected-error {{refers to class template member}}
{typename T::A F::*pm = 0;} // expected-error {{refers to class template member}}
{typename T::A (*fp)() = 0;} // expected-error {{refers to class template member}}
{typename T::A [x, y] = 0;} // expected-error {{cannot be declared with type 'typename T::A'}} expected-error {{type 'typename X::A<int>' (aka 'typename_specifier::X::A<int>') decomposes into 0}}
}
template void f<X>(); // expected-note {{instantiation of}}
template<typename T> void g(typename T::A = 0); // expected-note {{refers to class template member}}
void h() { g<X>(); } // expected-error {{no matching function}}
}
namespace parenthesized {
template<typename T> struct X { X(T); };
auto n = (X([]{}));
}
namespace within_template_arg_list {
template<typename T> struct X { constexpr X(T v) : v(v) {} T v; };
template<int N = X(1).v> struct Y {};
using T = Y<>;
using T = Y<X(1).v>;
using T = Y<within_template_arg_list::X(1).v>;
template<int ...N> struct Z { Y<X(N)...> y; };
}
namespace PR49735 {
// Ensure that we do not crash when parsing code which looks like an invalid
// deduction guide declaration.
template<class> struct B; // expected-note 2{{template is declared here}}
struct A1 {
B() noexcept(false); // expected-error {{deduction guide must be declared in the same scope as template 'PR49735::B'}} \
// expected-error {{deduction guide declaration without trailing return type}}
};
struct A2 {
template <typename Ty> // expected-note {{non-deducible template parameter 'Ty'}}
B() noexcept(false); // expected-error {{deduction guide must be declared in the same scope as template 'PR49735::B'}} \
// expected-error {{deduction guide template contains a template parameter that cannot be deduced}} \
// expected-error {{deduction guide declaration without trailing return type}}
};
}