1 /* nodiscard attribute tests, adapted from gcc.dg/attr-warn-unused-result.c. */
2 /* { dg-do compile } */
3 /* { dg-options "-std=c++17 -O -ftrack-macro-expansion=0" } */
4
5 #define WUR [[nodiscard]]
6 #define WURAI [[nodiscard, gnu::always_inline]] inline
7 enum [[nodiscard]] E { e };
8 typedef E (*fnt) (void);
9
10 typedef struct { long i; } A;
11 typedef struct { long i; long j; } B;
12 typedef struct { char big[1024]; fnt fn; } C;
13 struct [[nodiscard]] D { int i; D(); ~D(); };
14
15 WUR E check1 (void);
16 WUR void check2 (void); /* { dg-warning "nodiscard" } */
17 WUR int foo; /* { dg-warning "nodiscard" } */
18 int bar (void);
check3(void)19 WURAI E check3 (void) { return (E)bar (); }
20 WUR A check4 (void);
21 WUR B check5 (void);
22 WUR C check6 (void);
23 A bar7 (void);
24 B bar8 (void);
25 C bar9 (void);
check7(void)26 WURAI A check7 (void) { return bar7 (); }
check8(void)27 WURAI B check8 (void) { return bar8 (); }
check9(void)28 WURAI C check9 (void) { return bar9 (); }
29 /* This is useful for checking whether return value of statement
30 expressions (returning int in this case) is used. */
check_int_result(int res)31 WURAI int check_int_result (int res) { return res; }
32 #define GU(v) ({ int e = 0; (v) = bar (); if ((v) < 23) e = 14; e; })
33 fnt fnptr;
34 WUR E check10 (void);
35 int baz (void);
check11(void)36 WURAI E check11 (void) { return (E)baz (); }
37 int k;
38
39 D check12();
40
41 void
test(void)42 test (void)
43 {
44 int i = 0, j;
45 const fnt pcheck1 = check1;
46 const fnt pcheck3 = check3;
47 A a;
48 B b;
49 C c;
50 D d;
51 if (check1 ())
52 return;
53 i += check1 ();
54 i += ({ check1 (); });
55 check1 (); /* { dg-warning "nodiscard" } */
56 (void) check1 ();
57 check1 (), bar (); /* { dg-warning "nodiscard" } */
58 check2 ();
59 (void) check2 ();
60 check2 (), bar ();
61 if (check3 ())
62 return;
63 i += check3 ();
64 i += ({ check3 (); });
65 check3 (); /* { dg-warning "nodiscard" } */
66 (void) check3 ();
67 check3 (), bar (); /* { dg-warning "nodiscard" } */
68 a = check4 ();
69 if (a.i)
70 return;
71 if (check4 ().i)
72 return;
73 if (({ check4 (); }).i)
74 return;
75 check4 (); /* { dg-warning "nodiscard" } */
76 (void) check4 ();
77 check4 (), bar (); /* { dg-warning "nodiscard" } */
78 b = check5 ();
79 if (b.i + b.j)
80 return;
81 if (check5 ().j)
82 return;
83 if (({ check5 (); }).j)
84 return;
85 check5 (); /* { dg-warning "nodiscard" } */
86 (void) check5 ();
87 check5 (), bar (); /* { dg-warning "nodiscard" } */
88 c = check6 ();
89 if (c.big[12] + c.big[29])
90 return;
91 if (check6 ().big[27])
92 return;
93 if (({ check6 (); }).big[0])
94 return;
95 check6 (); /* { dg-warning "nodiscard" } */
96 (void) check6 ();
97 check6 (), bar (); /* { dg-warning "nodiscard" } */
98 a = check7 ();
99 if (a.i)
100 return;
101 if (check7 ().i)
102 return;
103 if (({ check7 (); }).i)
104 return;
105 check7 (); /* { dg-warning "nodiscard" } */
106 (void) check7 ();
107 check7 (), bar (); /* { dg-warning "nodiscard" } */
108 b = check8 ();
109 if (b.i + b.j)
110 return;
111 if (check8 ().j)
112 return;
113 if (({ check8 (); }).j)
114 return;
115 check8 (); /* { dg-warning "nodiscard" } */
116 (void) check8 ();
117 check8 (), bar (); /* { dg-warning "nodiscard" } */
118 c = check9 ();
119 if (c.big[12] + c.big[29])
120 return;
121 if (check9 ().big[27])
122 return;
123 if (({ check9 (); }).big[0])
124 return;
125 check9 (); /* { dg-warning "nodiscard" } */
126 (void) check9 ();
127 check9 (), bar (); /* { dg-warning "nodiscard" } */
128 if (check_int_result (GU (j)))
129 return;
130 i += check_int_result (GU (j));
131 i += ({ check_int_result (GU (j)); });
132 check_int_result (GU (j)); /* { dg-warning "nodiscard" } */
133 (void) check_int_result (GU (j));
134 check_int_result (GU (j)), bar (); /* { dg-warning "nodiscard" } */
135 if (fnptr ())
136 return;
137 i += fnptr ();
138 i += ({ fnptr (); });
139 fnptr (); /* { dg-warning "nodiscard" } */
140 (void) fnptr ();
141 fnptr (), bar (); /* { dg-warning "nodiscard" } */
142 fnptr = check1;
143 if (fnptr ())
144 return;
145 i += fnptr ();
146 i += ({ fnptr (); });
147 fnptr (); /* { dg-warning "nodiscard" } */
148 (void) fnptr ();
149 fnptr (), bar (); /* { dg-warning "nodiscard" } */
150 fnptr = check3;
151 if (fnptr ())
152 return;
153 i += fnptr ();
154 i += ({ fnptr (); });
155 fnptr (); /* { dg-warning "nodiscard" } */
156 (void) fnptr ();
157 fnptr (), bar (); /* { dg-warning "nodiscard" } */
158 if (bar9 ().fn ())
159 return;
160 i += bar9 ().fn ();
161 i += ({ bar9 ().fn (); });
162 bar9 ().fn (); /* { dg-warning "nodiscard" } */
163 (void) bar9 ().fn ();
164 bar9 ().fn (), bar (); /* { dg-warning "nodiscard" } */
165 if ((k ? check1 : check10) ())
166 return;
167 i += (k ? check1 : check10) ();
168 i += ({ (k ? check1 : check10) (); });
169 (k ? check1 : check10) (); /* { dg-warning "nodiscard" } */
170 (void) (k ? check1 : check10) ();
171 (k ? check1 : check10) (), bar (); /* { dg-warning "nodiscard" } */
172 if ((k ? check3 : check11) ())
173 return;
174 i += (k ? check3 : check11) ();
175 i += ({ (k ? check3 : check11) (); });
176 (k ? check3 : check11) (); /* { dg-warning "nodiscard" } */
177 (void) (k ? check3 : check11) ();
178 (k ? check3 : check11) (), bar (); /* { dg-warning "nodiscard" } */
179 if (pcheck1 ())
180 return;
181 i += pcheck1 ();
182 i += ({ pcheck1 (); });
183 pcheck1 (); /* { dg-warning "nodiscard" } */
184 (void) pcheck1 ();
185 pcheck1 (), bar (); /* { dg-warning "nodiscard" } */
186 if (pcheck3 ())
187 return;
188 i += pcheck3 ();
189 i += ({ pcheck3 (); });
190 pcheck3 (); /* { dg-warning "nodiscard" } */
191 (void) pcheck3 ();
192 pcheck3 (), bar (); /* { dg-warning "nodiscard" } */
193 d = check12 ();
194 if (d.i)
195 return;
196 if (check12 ().i)
197 return;
198 if (({ check12 (); }).i)
199 return;
200 check12 (); /* { dg-warning "nodiscard" } */
201 (void) check12 ();
202 check12 (), bar (); /* { dg-warning "nodiscard" } */
203 }
204