github.com/q45/go@v0.0.0-20151101211701-a4fb8c13db3f/src/go/types/testdata/decls3.src (about) 1 // Copyright 2012 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 // embedded types 6 7 package decls3 8 9 import "unsafe" 10 import "fmt" 11 12 // fields with the same name at the same level cancel each other out 13 14 func _() { 15 type ( 16 T1 struct { X int } 17 T2 struct { X int } 18 T3 struct { T1; T2 } // X is embedded twice at the same level via T1->X, T2->X 19 ) 20 21 var t T3 22 _ = t /* ERROR "ambiguous selector" */ .X 23 } 24 25 func _() { 26 type ( 27 T1 struct { X int } 28 T2 struct { T1 } 29 T3 struct { T1 } 30 T4 struct { T2; T3 } // X is embedded twice at the same level via T2->T1->X, T3->T1->X 31 ) 32 33 var t T4 34 _ = t /* ERROR "ambiguous selector" */ .X 35 } 36 37 func issue4355() { 38 type ( 39 T1 struct {X int} 40 T2 struct {T1} 41 T3 struct {T2} 42 T4 struct {T2} 43 T5 struct {T3; T4} // X is embedded twice at the same level via T3->T2->T1->X, T4->T2->T1->X 44 ) 45 46 var t T5 47 _ = t /* ERROR "ambiguous selector" */ .X 48 } 49 50 func _() { 51 type State int 52 type A struct{ State } 53 type B struct{ fmt.State } 54 type T struct{ A; B } 55 56 var t T 57 _ = t /* ERROR "ambiguous selector" */ .State 58 } 59 60 // Embedded fields can be predeclared types. 61 62 func _() { 63 type T0 struct{ 64 int 65 float32 66 f int 67 } 68 var x T0 69 _ = x.int 70 _ = x.float32 71 _ = x.f 72 73 type T1 struct{ 74 T0 75 } 76 var y T1 77 _ = y.int 78 _ = y.float32 79 _ = y.f 80 } 81 82 // Restrictions on embedded field types. 83 84 func _() { 85 type I1 interface{} 86 type I2 interface{} 87 type P1 *int 88 type P2 *int 89 type UP unsafe.Pointer 90 91 type T1 struct { 92 I1 93 * /* ERROR "cannot be a pointer to an interface" */ I2 94 * /* ERROR "cannot be a pointer to an interface" */ error 95 P1 /* ERROR "cannot be a pointer" */ 96 * /* ERROR "cannot be a pointer" */ P2 97 } 98 99 // unsafe.Pointers are treated like regular pointers when embedded 100 type T2 struct { 101 unsafe /* ERROR "cannot be unsafe.Pointer" */ .Pointer 102 */* ERROR "cannot be unsafe.Pointer" */ unsafe.Pointer 103 UP /* ERROR "cannot be unsafe.Pointer" */ 104 * /* ERROR "cannot be unsafe.Pointer" */ UP 105 } 106 } 107 108 // Named types that are pointers. 109 110 type S struct{ x int } 111 func (*S) m() {} 112 type P *S 113 114 func _() { 115 var s *S 116 _ = s.x 117 _ = s.m 118 119 var p P 120 _ = p.x 121 _ = p /* ERROR "no field or method" */ .m 122 _ = P /* ERROR "no field or method" */ .m 123 } 124 125 // Borrowed from the FieldByName test cases in reflect/all_test.go. 126 127 type D1 struct { 128 d int 129 } 130 type D2 struct { 131 d int 132 } 133 134 type S0 struct { 135 A, B, C int 136 D1 137 D2 138 } 139 140 type S1 struct { 141 B int 142 S0 143 } 144 145 type S2 struct { 146 A int 147 *S1 148 } 149 150 type S1x struct { 151 S1 152 } 153 154 type S1y struct { 155 S1 156 } 157 158 type S3 struct { 159 S1x 160 S2 161 D, E int 162 *S1y 163 } 164 165 type S4 struct { 166 *S4 167 A int 168 } 169 170 // The X in S6 and S7 annihilate, but they also block the X in S8.S9. 171 type S5 struct { 172 S6 173 S7 174 S8 175 } 176 177 type S6 struct { 178 X int 179 } 180 181 type S7 S6 182 183 type S8 struct { 184 S9 185 } 186 187 type S9 struct { 188 X int 189 Y int 190 } 191 192 // The X in S11.S6 and S12.S6 annihilate, but they also block the X in S13.S8.S9. 193 type S10 struct { 194 S11 195 S12 196 S13 197 } 198 199 type S11 struct { 200 S6 201 } 202 203 type S12 struct { 204 S6 205 } 206 207 type S13 struct { 208 S8 209 } 210 211 func _() { 212 _ = struct /* ERROR "no field or method" */ {}{}.Foo 213 _ = S0{}.A 214 _ = S0 /* ERROR "no field or method" */ {}.D 215 _ = S1{}.A 216 _ = S1{}.B 217 _ = S1{}.S0 218 _ = S1{}.C 219 _ = S2{}.A 220 _ = S2{}.S1 221 _ = S2{}.B 222 _ = S2{}.C 223 _ = S2 /* ERROR "no field or method" */ {}.D 224 _ = S3 /* ERROR "ambiguous selector" */ {}.S1 225 _ = S3{}.A 226 _ = S3 /* ERROR "ambiguous selector" */ {}.B 227 _ = S3{}.D 228 _ = S3{}.E 229 _ = S4{}.A 230 _ = S4 /* ERROR "no field or method" */ {}.B 231 _ = S5 /* ERROR "ambiguous selector" */ {}.X 232 _ = S5{}.Y 233 _ = S10 /* ERROR "ambiguous selector" */ {}.X 234 _ = S10{}.Y 235 } 236 237 // Borrowed from the FieldByName benchmark in reflect/all_test.go. 238 239 type R0 struct { 240 *R1 241 *R2 242 *R3 243 *R4 244 } 245 246 type R1 struct { 247 *R5 248 *R6 249 *R7 250 *R8 251 } 252 253 type R2 R1 254 type R3 R1 255 type R4 R1 256 257 type R5 struct { 258 *R9 259 *R10 260 *R11 261 *R12 262 } 263 264 type R6 R5 265 type R7 R5 266 type R8 R5 267 268 type R9 struct { 269 *R13 270 *R14 271 *R15 272 *R16 273 } 274 275 type R10 R9 276 type R11 R9 277 type R12 R9 278 279 type R13 struct { 280 *R17 281 *R18 282 *R19 283 *R20 284 } 285 286 type R14 R13 287 type R15 R13 288 type R16 R13 289 290 type R17 struct { 291 *R21 292 *R22 293 *R23 294 *R24 295 } 296 297 type R18 R17 298 type R19 R17 299 type R20 R17 300 301 type R21 struct { 302 X int 303 } 304 305 type R22 R21 306 type R23 R21 307 type R24 R21 308 309 var _ = R0 /* ERROR "ambiguous selector" */ {}.X