attr-lifetimebound.cpp source code [clang_source_code/test/SemaCXX/attr-lifetimebound.cpp]

1	// RUN: %clang_cc1 -std=c++2a -verify %s
2
3	namespace usage_invalid {
4	// FIXME: Should we diagnose a void return type?
5	void voidreturn(int &param [[clang::lifetimebound]]);
6
7	int *not_class_member() [[clang::lifetimebound]]; // expected-error {{non-member function has no implicit object parameter}}
8	struct A {
9	A() [[clang::lifetimebound]]; // expected-error {{cannot be applied to a constructor}}
10	~A() [[clang::lifetimebound]]; // expected-error {{cannot be applied to a destructor}}
11	static int *static_class_member() [[clang::lifetimebound]]; // expected-error {{static member function has no implicit object parameter}}
12	int not_function [[clang::lifetimebound]]; // expected-error {{only applies to parameters and implicit object parameters}}
13	int [[clang::lifetimebound]] also_not_function; // expected-error {{cannot be applied to types}}
14	};
15	int *attr_with_param(int &param [[clang::lifetimebound(42)]]); // expected-error {{takes no arguments}}
16	}
17
18	namespace usage_ok {
19	struct IntRef { int *target; };
20
21	int &refparam(int &param [[clang::lifetimebound]]);
22	int &classparam(IntRef param [[clang::lifetimebound]]);
23
24	// Do not diagnose non-void return types; they can still be lifetime-bound.
25	long long ptrintcast(int &param [[clang::lifetimebound]]) {
26	return (long long)&param;
27	}
28	// Likewise.
29	int &intptrcast(long long param [[clang::lifetimebound]]) {
30	return (int)param;
31	}
32
33	struct A {
34	A();
35	A(int);
36	int *class_member() [[clang::lifetimebound]];
37	operator int*() [[clang::lifetimebound]];
38	};
39
40	int *p = A().class_member(); // expected-warning {{temporary whose address is used as value of local variable 'p' will be destroyed at the end of the full-expression}}
41	int *q = A(); // expected-warning {{temporary whose address is used as value of local variable 'q' will be destroyed at the end of the full-expression}}
42	int *r = A(1); // expected-warning {{temporary whose address is used as value of local variable 'r' will be destroyed at the end of the full-expression}}
43	}
44
45	# 1 "<std>" 1 3
46	namespace std {
47	using size_t = __SIZE_TYPE__;
48	struct string {
49	string();
50	string(const char*);
51
52	char &operator[](size_t) const [[clang::lifetimebound]];
53	};
54	string operator""s(const char *, size_t);
55
56	struct string_view {
57	string_view();
58	string_view(const char *p [[clang::lifetimebound]]);
59	string_view(const string &s [[clang::lifetimebound]]);
60	};
61	string_view operator""sv(const char *, size_t);
62
63	struct vector {
64	int *data();
65	size_t size();
66	};
67
68	template<typename K, typename V> struct map {};
69	}
70	# 68 "attr-lifetimebound.cpp" 2
71
72	using std::operator""s;
73	using std::operator""sv;
74
75	namespace p0936r0_examples {
76	std::string_view s = "foo"s; // expected-warning {{temporary}}
77
78	std::string operator+(std::string_view s1, std::string_view s2);
79	void f() {
80	std::string_view sv = "hi";
81	std::string_view sv2 = sv + sv; // expected-warning {{temporary}}
82	sv2 = sv + sv; // FIXME: can we infer that we should warn here too?
83	}
84
85	struct X { int a, b; };
86	const int &f(const X &x [[clang::lifetimebound]]) { return x.a; }
87	const int &r = f(X()); // expected-warning {{temporary}}
88
89	char &c = std::string("hello my pretty long strong")[0]; // expected-warning {{temporary}}
90
91	struct reversed_range {
92	int *begin();
93	int *end();
94	int *p;
95	std::size_t n;
96	};
97	template <typename R> reversed_range reversed(R &&r [[clang::lifetimebound]]) {
98	return reversed_range{r.data(), r.size()};
99	}
100
101	std::vector make_vector();
102	void use_reversed_range() {
103	// FIXME: Don't expose the name of the internal range variable.
104	for (auto x : reversed(make_vector())) {} // expected-warning {{temporary implicitly bound to local reference will be destroyed at the end of the full-expression}}
105	}
106
107	template <typename K, typename V>
108	const V &findOrDefault(const std::map<K, V> &m [[clang::lifetimebound]],
109	const K &key,
110	const V &defvalue [[clang::lifetimebound]]);
111
112	// FIXME: Maybe weaken the wording here: "local reference 'v' could bind to temporary that will be destroyed at end of full-expression"?
113	std::map<std::string, std::string> m;
114	const std::string &v = findOrDefault(m, "foo"s, "bar"s); // expected-warning {{temporary bound to local reference 'v'}}
115	}
116

Clang Project