1 // RUN: %clang_cc1 -fcxx-exceptions -fdeclspec -fexceptions -fsyntax-only -verify -std=c++11 -Wc++14-compat -Wc++14-extensions -Wc++17-extensions %s
2 
3 // Need std::initializer_list
4 namespace std {
5   typedef decltype(sizeof(int)) size_t;
6 
7   // libc++'s implementation
8   template <class _E>
9   class initializer_list
10   {
11     const _E* __begin_;
12     size_t    __size_;
13 
14     initializer_list(const _E* __b, size_t __s)
15       : __begin_(__b),
16         __size_(__s)
17     {}
18 
19   public:
20     typedef _E        value_type;
21     typedef const _E& reference;
22     typedef const _E& const_reference;
23     typedef size_t    size_type;
24 
25     typedef const _E* iterator;
26     typedef const _E* const_iterator;
27 
28     initializer_list() : __begin_(nullptr), __size_(0) {}
29 
30     size_t    size()  const {return __size_;}
31     const _E* begin() const {return __begin_;}
32     const _E* end()   const {return __begin_ + __size_;}
33   };
34 }
35 
36 
37 // Declaration syntax checks
38 [[]] int before_attr;
39 int [[]] between_attr;
40 const [[]] int between_attr_2 = 0; // expected-error {{an attribute list cannot appear here}}
41 int after_attr [[]];
42 int * [[]] ptr_attr;
43 int & [[]] ref_attr = after_attr;
44 int & [[unknown]] ref_attr_2 = after_attr; // expected-warning {{unknown attribute 'unknown' ignored}}
45 int & [[noreturn]] ref_attr_3 = after_attr; // expected-error {{'noreturn' attribute cannot be applied to types}}
46 int && [[]] rref_attr = 0;
47 int array_attr [1] [[]];
48 alignas(8) int aligned_attr;
49 [[test::valid(for 42 [very] **** '+' symbols went on a trip and had a "good"_time; the end.)]] int garbage_attr; // expected-warning {{unknown attribute 'valid' ignored}}
50 [[,,,static, class, namespace,, inline, constexpr, mutable,, bitand, bitor::compl(!.*_ Cx.!U^*R),,,]] int more_garbage_attr; // expected-warning {{unknown attribute 'static' ignored}} \
51     // expected-warning {{unknown attribute 'class' ignored}} \
52     // expected-warning {{unknown attribute 'namespace' ignored}} \
53     // expected-warning {{unknown attribute 'inline' ignored}} \
54     // expected-warning {{unknown attribute 'constexpr' ignored}} \
55     // expected-warning {{unknown attribute 'mutable' ignored}} \
56     // expected-warning {{unknown attribute 'bitand' ignored}} \
57     // expected-warning {{unknown attribute 'compl' ignored}}
58 [[u8"invalid!"]] int invalid_string_attr; // expected-error {{expected ']'}}
59 void fn_attr () [[]];
60 void noexcept_fn_attr () noexcept [[]];
61 struct MemberFnOrder {
62   virtual void f() const volatile && noexcept [[]] final = 0;
63 };
64 struct [[]] struct_attr;
65 class [[]] class_attr {};
66 union [[]] union_attr;
67 enum [[]] E { };
68 namespace test_misplacement {
69 [[]] struct struct_attr2;  //expected-error{{misplaced attributes}}
70 [[]] class class_attr2; //expected-error{{misplaced attributes}}
71 [[]] union union_attr2; //expected-error{{misplaced attributes}}
72 [[]] enum  E2 { }; //expected-error{{misplaced attributes}}
73 }
74 
75 // Checks attributes placed at wrong syntactic locations of class specifiers.
76 class [[]] [[]]
77   attr_after_class_name_decl [[]] [[]]; // expected-error {{an attribute list cannot appear here}}
78 
79 class [[]] [[]]
80  attr_after_class_name_definition [[]] [[]] [[]]{}; // expected-error {{an attribute list cannot appear here}}
81 
82 class [[]] c {};
83 class c [[]] [[]] x;
84 class c [[]] [[]] y [[]] [[]];
85 class c final [(int){0}];
86 
87 class base {};
88 class [[]] [[]] final_class
89   alignas(float) [[]] final // expected-error {{an attribute list cannot appear here}}
90   alignas(float) [[]] [[]] alignas(float): base{}; // expected-error {{an attribute list cannot appear here}}
91 
92 class [[]] [[]] final_class_another
93   [[]] [[]] alignas(16) final // expected-error {{an attribute list cannot appear here}}
94   [[]] [[]] alignas(16) [[]]{}; // expected-error {{an attribute list cannot appear here}}
95 
96 // The diagnostics here don't matter much, this just shouldn't crash:
97 class C final [[deprecated(l]] {}); // expected-error {{use of undeclared identifier}} expected-error {{expected ']'}} expected-error {{an attribute list cannot appear here}} expected-error {{expected unqualified-id}}
98 class D final alignas ([l) {}]{}); // expected-error {{expected ',' or ']' in lambda capture list}} expected-error {{an attribute list cannot appear here}}
99 
100 [[]] struct with_init_declarators {} init_declarator;
101 [[]] struct no_init_declarators; // expected-error {{misplaced attributes}}
102 template<typename> [[]] struct no_init_declarators_template; // expected-error {{an attribute list cannot appear here}}
103 void fn_with_structs() {
104   [[]] struct with_init_declarators {} init_declarator;
105   [[]] struct no_init_declarators; // expected-error {{an attribute list cannot appear here}}
106 }
107 [[]];
108 struct ctordtor {
109   [[]] ctordtor [[]] () [[]];
110   ctordtor (C) [[]];
111   [[]] ~ctordtor [[]] () [[]];
112 };
113 [[]] ctordtor::ctordtor [[]] () [[]] {}
114 [[]] ctordtor::ctordtor (C) [[]] try {} catch (...) {}
115 [[]] ctordtor::~ctordtor [[]] () [[]] {}
116 extern "C++" [[]] int extern_attr;
117 template <typename T> [[]] void template_attr ();
118 [[]] [[]] int [[]] [[]] multi_attr [[]] [[]];
119 
120 int comma_attr [[,]];
121 int scope_attr [[foo::]]; // expected-error {{expected identifier}}
122 int (paren_attr) [[]]; // expected-error {{an attribute list cannot appear here}}
123 unsigned [[]] int attr_in_decl_spec; // expected-error {{an attribute list cannot appear here}}
124 unsigned [[]] int [[]] const double_decl_spec = 0; // expected-error 2{{an attribute list cannot appear here}}
125 class foo {
126   void const_after_attr () [[]] const; // expected-error {{expected ';'}}
127 };
128 extern "C++" [[]] { } // expected-error {{an attribute list cannot appear here}}
129 [[]] template <typename T> void before_template_attr (); // expected-error {{an attribute list cannot appear here}}
130 [[]] namespace ns { int i; } // expected-error {{an attribute list cannot appear here}} expected-note {{declared here}}
131 [[]] static_assert(true, ""); //expected-error {{an attribute list cannot appear here}}
132 [[]] asm(""); // expected-error {{an attribute list cannot appear here}}
133 
134 [[]] using ns::i;
135 [[unknown]] using namespace ns; // expected-warning {{unknown attribute 'unknown' ignored}}
136 [[noreturn]] using namespace ns; // expected-error {{'noreturn' attribute only applies to functions}}
137 namespace [[]] ns2 {} // expected-warning {{attributes on a namespace declaration are a C++17 extension}}
138 
139 using[[]] alignas(4)[[]] ns::i;          // expected-error {{an attribute list cannot appear here}} expected-error {{'alignas' attribute only applies to variables, data members and tag types}} expected-warning {{ISO C++}}
140 using [[]] alignas(4) [[]] foobar = int; // expected-error {{an attribute list cannot appear here}} expected-error {{'alignas' attribute only applies to}}
141 
142 void bad_attributes_in_do_while() {
143   do {} while (
144       [[ns::i); // expected-error {{expected ']'}} \
145                 // expected-note {{to match this '['}} \
146                 // expected-error {{expected expression}}
147   do {} while (
148       [[a]b ns::i); // expected-error {{expected ']'}} \
149                     // expected-note {{to match this '['}} \
150                     // expected-error {{expected expression}}
151   do {} while (
152       [[ab]ab] ns::i); // expected-error {{an attribute list cannot appear here}}
153   do {} while ( // expected-note {{to match this '('}}
154       alignas(4 ns::i; // expected-note {{to match this '('}}
155 } // expected-error 2{{expected ')'}} expected-error {{expected expression}}
156 
157 [[]] using T = int; // expected-error {{an attribute list cannot appear here}}
158 using T [[]] = int; // ok
159 template<typename T> using U [[]] = T;
160 using ns::i [[]];
161 using ns::i [[]], ns::i [[]]; // expected-warning {{use of multiple declarators in a single using declaration is a C++17 extension}}
162 struct using_in_struct_base {
163   typedef int i, j, k, l;
164 };
165 struct using_in_struct : using_in_struct_base {
166   [[]] using using_in_struct_base::i;
167   using using_in_struct_base::j [[]];
168   [[]] using using_in_struct_base::k [[]], using_in_struct_base::l [[]]; // expected-warning {{use of multiple declarators in a single using declaration is a C++17 extension}}
169 };
170 using [[]] ns::i; // expected-error {{an attribute list cannot appear here}}
171 using T [[unknown]] = int; // expected-warning {{unknown attribute 'unknown' ignored}}
172 using T [[noreturn]] = int; // expected-error {{'noreturn' attribute only applies to functions}}
173 using V = int; // expected-note {{previous}}
174 using V [[gnu::vector_size(16)]] = int; // expected-error {{redefinition with different types}}
175 
176 auto trailing() -> [[]] const int; // expected-error {{an attribute list cannot appear here}}
177 auto trailing() -> const [[]] int; // expected-error {{an attribute list cannot appear here}}
178 auto trailing() -> const int [[]];
179 auto trailing_2() -> struct struct_attr [[]];
180 
181 namespace N {
182   struct S {};
183 };
184 template<typename> struct Template {};
185 
186 // FIXME: Improve this diagnostic
187 struct [[]] N::S s; // expected-error {{an attribute list cannot appear here}}
188 struct [[]] Template<int> t; // expected-error {{an attribute list cannot appear here}}
189 struct [[]] ::template Template<int> u; // expected-error {{an attribute list cannot appear here}}
190 template struct [[]] Template<char>; // expected-error {{an attribute list cannot appear here}}
191 template struct __attribute__((pure)) Template<std::size_t>; // We still allow GNU-style attributes here
192 template <> struct [[]] Template<void>;
193 
194 enum [[]] E1 {};
195 enum [[]] E2; // expected-error {{forbids forward references}}
196 enum [[]] E1;
197 enum [[]] E3 : int;
198 enum [[]] {
199   k_123 [[]] = 123 // expected-warning {{attributes on an enumerator declaration are a C++17 extension}}
200 };
201 enum [[]] E1 e; // expected-error {{an attribute list cannot appear here}}
202 enum [[]] class E4 { }; // expected-error {{an attribute list cannot appear here}}
203 enum struct [[]] E5;
204 
205 struct S {
206   friend int f [[]] (); // expected-FIXME{{an attribute list cannot appear here}}
207   friend int f1 [[noreturn]] (); //expected-error{{an attribute list cannot appear here}}
208   friend int f2 [[]] [[noreturn]] () {}
209   [[]] friend int g(); // expected-error{{an attribute list cannot appear here}}
210   [[]] friend int h() {
211   }
212   [[]] friend int f3(), f4(), f5(); // expected-error{{an attribute list cannot appear here}}
213   friend int f6 [[noreturn]] (), f7 [[noreturn]] (), f8 [[noreturn]] (); // expected-error3 {{an attribute list cannot appear here}}
214   friend class [[]] C; // expected-error{{an attribute list cannot appear here}}
215   [[]] friend class D; // expected-error{{an attribute list cannot appear here}}
216   [[]] friend int; // expected-error{{an attribute list cannot appear here}}
217 };
218 template<typename T> void tmpl(T) {}
219 template void tmpl [[]] (int); // expected-FIXME {{an attribute list cannot appear here}}
220 template [[]] void tmpl(char); // expected-error {{an attribute list cannot appear here}}
221 template void [[]] tmpl(short);
222 
223 // Argument tests
224 alignas int aligned_no_params; // expected-error {{expected '('}}
225 alignas(i) int aligned_nonconst; // expected-error {{'aligned' attribute requires integer constant}} expected-note {{read of non-const variable 'i'}}
226 
227 // Statement tests
228 void foo () {
229   [[]] ;
230   [[]] { }
231   [[]] if (0) { }
232   [[]] for (;;);
233   [[]] do {
234     [[]] continue;
235   } while (0);
236   [[]] while (0);
237 
238   [[]] switch (i) {
239     [[]] case 0:
240     [[]] default:
241       [[]] break;
242   }
243 
244   [[]] goto there;
245   [[]] there:
246 
247   [[]] try {
248   } [[]] catch (...) { // expected-error {{an attribute list cannot appear here}}
249   }
250   struct S { int arr[2]; } s;
251   (void)s.arr[ [] { return 0; }() ]; // expected-error {{C++11 only allows consecutive left square brackets when introducing an attribute}}
252   int n = __builtin_offsetof(S, arr[ [] { return 0; }() ]); // expected-error {{C++11 only allows consecutive left square brackets when introducing an attribute}}
253 
254   void bar [[noreturn]] ([[]] int i, [[]] int j);
255   using FuncType = void ([[]] int);
256   void baz([[]]...); // expected-error {{expected parameter declarator}}
257 
258   [[]] return;
259 }
260 
261 template<typename...Ts> void variadic() {
262   void bar [[noreturn...]] (); // expected-error {{attribute 'noreturn' cannot be used as an attribute pack}}
263 }
264 
265 // Expression tests
266 void bar () {
267   // FIXME: GCC accepts [[gnu::noreturn]] on a lambda, even though it appertains
268   // to the operator()'s type, and GCC does not otherwise accept attributes
269   // applied to types. Use that to test this.
270   [] () [[gnu::noreturn]] { return; } (); // expected-warning {{attribute 'noreturn' ignored}} FIXME-error {{should not return}}
271   [] () [[gnu::noreturn]] { throw; } (); // expected-warning {{attribute 'noreturn' ignored}}
272   new int[42][[]][5][[]]{};
273 }
274 
275 // Condition tests
276 void baz () {
277   if ([[unknown]] bool b = true) { // expected-warning {{unknown attribute 'unknown' ignored}}
278     switch ([[unknown]] int n { 42 }) { // expected-warning {{unknown attribute 'unknown' ignored}}
279     default:
280       for ([[unknown]] int n = 0; [[unknown]] char b = n < 5; ++b) { // expected-warning 2{{unknown attribute 'unknown' ignored}}
281       }
282     }
283   }
284   int x;
285   // An attribute can be applied to an expression-statement, such as the first
286   // statement in a for. But it can't be applied to a condition which is an
287   // expression.
288   for ([[]] x = 0; ; ) {} // expected-error {{an attribute list cannot appear here}}
289   for (; [[]] x < 5; ) {} // expected-error {{an attribute list cannot appear here}}
290   while ([[]] bool k { false }) {
291   }
292   while ([[]] true) { // expected-error {{an attribute list cannot appear here}}
293   }
294   do {
295   } while ([[]] false); // expected-error {{an attribute list cannot appear here}}
296 
297   for ([[unknown]] int n : { 1, 2, 3 }) { // expected-warning {{unknown attribute 'unknown' ignored}}
298   }
299 }
300 
301 enum class __attribute__((visibility("hidden"))) SecretKeepers {
302   one, /* rest are deprecated */ two, three
303 };
304 enum class [[]] EvenMoreSecrets {};
305 
306 namespace arguments {
307   void f[[gnu::format(printf, 1, 2)]](const char*, ...);
308   void g() [[unknown::foo(ignore arguments for unknown attributes, even with symbols!)]]; // expected-warning {{unknown attribute 'foo' ignored}}
309   [[deprecated("with argument")]] int i;
310   // expected-warning@-1 {{use of the 'deprecated' attribute is a C++14 extension}}
311 }
312 
313 // Forbid attributes on decl specifiers.
314 unsigned [[gnu::used]] static int [[gnu::unused]] v1; // expected-error {{'unused' attribute cannot be applied to types}} \
315            expected-error {{an attribute list cannot appear here}}
316 typedef [[gnu::used]] unsigned long [[gnu::unused]] v2; // expected-error {{'unused' attribute cannot be applied to types}} \
317           expected-error {{an attribute list cannot appear here}}
318 int [[carries_dependency]] foo(int [[carries_dependency]] x); // expected-error 2{{'carries_dependency' attribute cannot be applied to types}}
319 
320 // Forbid [[gnu::...]] attributes on declarator chunks.
321 int *[[gnu::unused]] v3; // expected-warning {{attribute 'unused' ignored}}
322 int v4[2][[gnu::unused]]; // expected-warning {{attribute 'unused' ignored}}
323 int v5()[[gnu::unused]]; // expected-warning {{attribute 'unused' ignored}}
324 
325 [[attribute_declaration]]; // expected-warning {{unknown attribute 'attribute_declaration' ignored}}
326 [[noreturn]]; // expected-error {{'noreturn' attribute only applies to functions}}
327 [[carries_dependency]]; // expected-error {{'carries_dependency' attribute only applies to parameters, Objective-C methods, and functions}}
328 
329 class A {
330   A([[gnu::unused]] int a);
331 };
332 A::A([[gnu::unused]] int a) {}
333 
334 namespace GccConst {
335   // GCC's tokenizer treats const and __const as the same token.
336   [[gnu::const]] int *f1();
337   [[gnu::__const]] int *f2();
338   [[gnu::__const__]] int *f3();
339   void f(const int *);
340   void g() { f(f1()); f(f2()); }
341   void h() { f(f3()); }
342 }
343 
344 namespace GccASan {
345   __attribute__((no_address_safety_analysis)) void f1();
346   __attribute__((no_sanitize_address)) void f2();
347   [[gnu::no_address_safety_analysis]] void f3();
348   [[gnu::no_sanitize_address]] void f4();
349 }
350 
351 namespace {
352   [[deprecated]] void bar();
353   // expected-warning@-1 {{use of the 'deprecated' attribute is a C++14 extension}}
354   [[deprecated("hello")]] void baz();
355   // expected-warning@-1 {{use of the 'deprecated' attribute is a C++14 extension}}
356   [[deprecated()]] void foo();
357   // expected-error@-1 {{parentheses must be omitted if 'deprecated' attribute's argument list is empty}}
358   [[gnu::deprecated()]] void quux();
359 }
360 
361 namespace {
362 [[ // expected-error {{expected ']'}}
363 #pragma pack(pop)
364 deprecated
365 ]] void bad();
366 }
367 
368 int fallthru(int n) {
369   switch (n) {
370   case 0:
371     n += 5;
372     [[fallthrough]]; // expected-warning {{use of the 'fallthrough' attribute is a C++17 extension}}
373   case 1:
374     n *= 2;
375     break;
376   }
377   return n;
378 }
379 
380 template<typename T> struct TemplateStruct {};
381 class FriendClassesWithAttributes {
382   // We allow GNU-style attributes here
383   template <class _Tp, class _Alloc> friend class __attribute__((__type_visibility__("default"))) vector;
384   template <class _Tp, class _Alloc> friend class __declspec(code_seg("foo,whatever")) vector2;
385   // But not C++11 ones
386   template <class _Tp, class _Alloc> friend class[[]] vector3;                                         // expected-error {{an attribute list cannot appear here}}
387   template <class _Tp, class _Alloc> friend class [[clang::__type_visibility__(("default"))]] vector4; // expected-error {{an attribute list cannot appear here}}
388 
389   // Also allowed
390   friend struct __attribute__((__type_visibility__("default"))) TemplateStruct<FriendClassesWithAttributes>;
391   friend struct __declspec(code_seg("foo,whatever")) TemplateStruct<FriendClassesWithAttributes>;
392   friend struct[[]] TemplateStruct<FriendClassesWithAttributes>;                                       // expected-error {{an attribute list cannot appear here}}
393   friend struct [[clang::__type_visibility__("default")]] TemplateStruct<FriendClassesWithAttributes>; // expected-error {{an attribute list cannot appear here}}
394 };
395 
396 #define attr_name bitand
397 #define attr_name_2(x) x
398 #define attr_name_3(x, y) x##y
399 [[attr_name, attr_name_2(bitor), attr_name_3(com, pl)]] int macro_attrs; // expected-warning {{unknown attribute 'compl' ignored}} \
400    expected-warning {{unknown attribute 'bitor' ignored}} \
401    expected-warning {{unknown attribute 'bitand' ignored}}
402 
403 // Check that we can parse an attribute in our vendor namespace.
404 [[clang::annotate("test")]] void annotate1();
405 [[_Clang::annotate("test")]] void annotate2();
406 // Note: __clang__ is a predefined macro, which is why _Clang is the
407 // prefered "protected" vendor namespace. We support __clang__ only for
408 // people expecting it to behave the same as __gnu__.
409 [[__clang__::annotate("test")]] void annotate3();  // expected-warning {{'__clang__' is a predefined macro name, not an attribute scope specifier; did you mean '_Clang' instead?}}
410