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Commit | Line | Data |
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dfeec247 XL |
1 | error[E0308]: mismatched types |
2 | --> $DIR/dyn-trait-return-should-be-impl-trait.rs:7:35 | |
3 | | | |
4 | LL | fn fuz() -> (usize, Trait) { (42, Struct) } | |
5 | | ^^^^^^ expected trait object `dyn Trait`, found struct `Struct` | |
6 | | | |
7 | = note: expected trait object `(dyn Trait + 'static)` | |
8 | found struct `Struct` | |
9 | ||
10 | error[E0277]: the size for values of type `(dyn Trait + 'static)` cannot be known at compilation time | |
11 | --> $DIR/dyn-trait-return-should-be-impl-trait.rs:7:13 | |
12 | | | |
13 | LL | fn fuz() -> (usize, Trait) { (42, Struct) } | |
14 | | ^^^^^^^^^^^^^^ ------------ this returned value is of type `(usize, (dyn Trait + 'static))` | |
15 | | | | |
16 | | doesn't have a size known at compile-time | |
17 | | | |
1b1a35ee | 18 | = help: within `(usize, (dyn Trait + 'static))`, the trait `Sized` is not implemented for `(dyn Trait + 'static)` |
dfeec247 XL |
19 | = note: required because it appears within the type `(usize, (dyn Trait + 'static))` |
20 | = note: the return type of a function must have a statically known size | |
21 | ||
22 | error[E0308]: mismatched types | |
23 | --> $DIR/dyn-trait-return-should-be-impl-trait.rs:10:39 | |
24 | | | |
25 | LL | fn bar() -> (usize, dyn Trait) { (42, Struct) } | |
26 | | ^^^^^^ expected trait object `dyn Trait`, found struct `Struct` | |
27 | | | |
28 | = note: expected trait object `(dyn Trait + 'static)` | |
29 | found struct `Struct` | |
30 | ||
31 | error[E0277]: the size for values of type `(dyn Trait + 'static)` cannot be known at compilation time | |
32 | --> $DIR/dyn-trait-return-should-be-impl-trait.rs:10:13 | |
33 | | | |
34 | LL | fn bar() -> (usize, dyn Trait) { (42, Struct) } | |
35 | | ^^^^^^^^^^^^^^^^^^ ------------ this returned value is of type `(usize, (dyn Trait + 'static))` | |
36 | | | | |
37 | | doesn't have a size known at compile-time | |
38 | | | |
1b1a35ee | 39 | = help: within `(usize, (dyn Trait + 'static))`, the trait `Sized` is not implemented for `(dyn Trait + 'static)` |
dfeec247 XL |
40 | = note: required because it appears within the type `(usize, (dyn Trait + 'static))` |
41 | = note: the return type of a function must have a statically known size | |
42 | ||
43 | error[E0746]: return type cannot have an unboxed trait object | |
44 | --> $DIR/dyn-trait-return-should-be-impl-trait.rs:13:13 | |
45 | | | |
46 | LL | fn bap() -> Trait { Struct } | |
47 | | ^^^^^ doesn't have a size known at compile-time | |
48 | | | |
49 | = note: for information on `impl Trait`, see <https://doc.rust-lang.org/book/ch10-02-traits.html#returning-types-that-implement-traits> | |
f9f354fc | 50 | help: use `impl Trait` as the return type, as all return paths are of type `Struct`, which implements `Trait` |
dfeec247 XL |
51 | | |
52 | LL | fn bap() -> impl Trait { Struct } | |
53 | | ^^^^^^^^^^ | |
54 | ||
55 | error[E0746]: return type cannot have an unboxed trait object | |
56 | --> $DIR/dyn-trait-return-should-be-impl-trait.rs:15:13 | |
57 | | | |
58 | LL | fn ban() -> dyn Trait { Struct } | |
59 | | ^^^^^^^^^ doesn't have a size known at compile-time | |
60 | | | |
61 | = note: for information on `impl Trait`, see <https://doc.rust-lang.org/book/ch10-02-traits.html#returning-types-that-implement-traits> | |
f9f354fc | 62 | help: use `impl Trait` as the return type, as all return paths are of type `Struct`, which implements `Trait` |
dfeec247 XL |
63 | | |
64 | LL | fn ban() -> impl Trait { Struct } | |
65 | | ^^^^^^^^^^ | |
66 | ||
f9f354fc | 67 | error[E0746]: return type cannot have an unboxed trait object |
dfeec247 XL |
68 | --> $DIR/dyn-trait-return-should-be-impl-trait.rs:17:13 |
69 | | | |
70 | LL | fn bak() -> dyn Trait { unimplemented!() } | |
71 | | ^^^^^^^^^ doesn't have a size known at compile-time | |
72 | | | |
f9f354fc XL |
73 | help: use some type `T` that is `T: Sized` as the return type if all return paths have the same type |
74 | | | |
75 | LL | fn bak() -> T { unimplemented!() } | |
76 | | ^ | |
77 | help: use `impl Trait` as the return type if all return paths have the same type but you want to expose only the trait in the signature | |
78 | | | |
79 | LL | fn bak() -> impl Trait { unimplemented!() } | |
80 | | ^^^^^^^^^^ | |
81 | help: use a boxed trait object if all return paths implement trait `Trait` | |
82 | | | |
83 | LL | fn bak() -> Box<dyn Trait> { unimplemented!() } | |
84 | | ^^^^^^^^^^^^^^ | |
dfeec247 XL |
85 | |
86 | error[E0746]: return type cannot have an unboxed trait object | |
87 | --> $DIR/dyn-trait-return-should-be-impl-trait.rs:19:13 | |
88 | | | |
89 | LL | fn bal() -> dyn Trait { | |
90 | | ^^^^^^^^^ doesn't have a size known at compile-time | |
91 | | | |
92 | = note: for information on trait objects, see <https://doc.rust-lang.org/book/ch17-02-trait-objects.html#using-trait-objects-that-allow-for-values-of-different-types> | |
93 | = note: if all the returned values were of the same type you could use `impl Trait` as the return type | |
94 | = note: for information on `impl Trait`, see <https://doc.rust-lang.org/book/ch10-02-traits.html#returning-types-that-implement-traits> | |
95 | = note: you can create a new `enum` with a variant for each returned type | |
96 | help: return a boxed trait object instead | |
97 | | | |
98 | LL | fn bal() -> Box<dyn Trait> { | |
99 | LL | if true { | |
100 | LL | return Box::new(Struct); | |
101 | LL | } | |
102 | LL | Box::new(42) | |
103 | | | |
104 | ||
f9f354fc XL |
105 | error[E0308]: `if` and `else` have incompatible types |
106 | --> $DIR/dyn-trait-return-should-be-impl-trait.rs:29:9 | |
107 | | | |
108 | LL | / if true { | |
109 | LL | | Struct | |
110 | | | ------ expected because of this | |
111 | LL | | } else { | |
112 | LL | | 42 | |
113 | | | ^^ expected struct `Struct`, found integer | |
114 | LL | | } | |
115 | | |_____- `if` and `else` have incompatible types | |
116 | ||
dfeec247 XL |
117 | error[E0746]: return type cannot have an unboxed trait object |
118 | --> $DIR/dyn-trait-return-should-be-impl-trait.rs:25:13 | |
119 | | | |
120 | LL | fn bax() -> dyn Trait { | |
121 | | ^^^^^^^^^ doesn't have a size known at compile-time | |
122 | | | |
123 | = note: for information on trait objects, see <https://doc.rust-lang.org/book/ch17-02-trait-objects.html#using-trait-objects-that-allow-for-values-of-different-types> | |
124 | = note: if all the returned values were of the same type you could use `impl Trait` as the return type | |
125 | = note: for information on `impl Trait`, see <https://doc.rust-lang.org/book/ch10-02-traits.html#returning-types-that-implement-traits> | |
126 | = note: you can create a new `enum` with a variant for each returned type | |
127 | help: return a boxed trait object instead | |
128 | | | |
129 | LL | fn bax() -> Box<dyn Trait> { | |
130 | LL | if true { | |
131 | LL | Box::new(Struct) | |
132 | LL | } else { | |
133 | LL | Box::new(42) | |
134 | | | |
135 | ||
136 | error[E0308]: mismatched types | |
137 | --> $DIR/dyn-trait-return-should-be-impl-trait.rs:34:16 | |
138 | | | |
139 | LL | fn bam() -> Box<dyn Trait> { | |
1b1a35ee | 140 | | -------------- expected `Box<(dyn Trait + 'static)>` because of return type |
dfeec247 XL |
141 | LL | if true { |
142 | LL | return Struct; | |
143 | | ^^^^^^ | |
144 | | | | |
1b1a35ee | 145 | | expected struct `Box`, found struct `Struct` |
dfeec247 XL |
146 | | help: store this in the heap by calling `Box::new`: `Box::new(Struct)` |
147 | | | |
1b1a35ee | 148 | = note: expected struct `Box<(dyn Trait + 'static)>` |
dfeec247 XL |
149 | found struct `Struct` |
150 | = note: for more on the distinction between the stack and the heap, read https://doc.rust-lang.org/book/ch15-01-box.html, https://doc.rust-lang.org/rust-by-example/std/box.html, and https://doc.rust-lang.org/std/boxed/index.html | |
151 | ||
152 | error[E0308]: mismatched types | |
153 | --> $DIR/dyn-trait-return-should-be-impl-trait.rs:36:5 | |
154 | | | |
155 | LL | fn bam() -> Box<dyn Trait> { | |
1b1a35ee | 156 | | -------------- expected `Box<(dyn Trait + 'static)>` because of return type |
dfeec247 XL |
157 | ... |
158 | LL | 42 | |
159 | | ^^ | |
160 | | | | |
1b1a35ee | 161 | | expected struct `Box`, found integer |
dfeec247 XL |
162 | | help: store this in the heap by calling `Box::new`: `Box::new(42)` |
163 | | | |
1b1a35ee | 164 | = note: expected struct `Box<(dyn Trait + 'static)>` |
dfeec247 XL |
165 | found type `{integer}` |
166 | = note: for more on the distinction between the stack and the heap, read https://doc.rust-lang.org/book/ch15-01-box.html, https://doc.rust-lang.org/rust-by-example/std/box.html, and https://doc.rust-lang.org/std/boxed/index.html | |
167 | ||
168 | error[E0308]: mismatched types | |
169 | --> $DIR/dyn-trait-return-should-be-impl-trait.rs:40:16 | |
170 | | | |
171 | LL | fn baq() -> Box<dyn Trait> { | |
1b1a35ee | 172 | | -------------- expected `Box<(dyn Trait + 'static)>` because of return type |
dfeec247 XL |
173 | LL | if true { |
174 | LL | return 0; | |
175 | | ^ | |
176 | | | | |
1b1a35ee | 177 | | expected struct `Box`, found integer |
dfeec247 XL |
178 | | help: store this in the heap by calling `Box::new`: `Box::new(0)` |
179 | | | |
1b1a35ee | 180 | = note: expected struct `Box<(dyn Trait + 'static)>` |
dfeec247 XL |
181 | found type `{integer}` |
182 | = note: for more on the distinction between the stack and the heap, read https://doc.rust-lang.org/book/ch15-01-box.html, https://doc.rust-lang.org/rust-by-example/std/box.html, and https://doc.rust-lang.org/std/boxed/index.html | |
183 | ||
184 | error[E0308]: mismatched types | |
185 | --> $DIR/dyn-trait-return-should-be-impl-trait.rs:42:5 | |
186 | | | |
187 | LL | fn baq() -> Box<dyn Trait> { | |
1b1a35ee | 188 | | -------------- expected `Box<(dyn Trait + 'static)>` because of return type |
dfeec247 XL |
189 | ... |
190 | LL | 42 | |
191 | | ^^ | |
192 | | | | |
1b1a35ee | 193 | | expected struct `Box`, found integer |
dfeec247 XL |
194 | | help: store this in the heap by calling `Box::new`: `Box::new(42)` |
195 | | | |
1b1a35ee | 196 | = note: expected struct `Box<(dyn Trait + 'static)>` |
dfeec247 XL |
197 | found type `{integer}` |
198 | = note: for more on the distinction between the stack and the heap, read https://doc.rust-lang.org/book/ch15-01-box.html, https://doc.rust-lang.org/rust-by-example/std/box.html, and https://doc.rust-lang.org/std/boxed/index.html | |
199 | ||
200 | error[E0308]: mismatched types | |
201 | --> $DIR/dyn-trait-return-should-be-impl-trait.rs:46:9 | |
202 | | | |
203 | LL | fn baz() -> Box<dyn Trait> { | |
1b1a35ee | 204 | | -------------- expected `Box<(dyn Trait + 'static)>` because of return type |
dfeec247 XL |
205 | LL | if true { |
206 | LL | Struct | |
207 | | ^^^^^^ | |
208 | | | | |
1b1a35ee | 209 | | expected struct `Box`, found struct `Struct` |
dfeec247 XL |
210 | | help: store this in the heap by calling `Box::new`: `Box::new(Struct)` |
211 | | | |
1b1a35ee | 212 | = note: expected struct `Box<(dyn Trait + 'static)>` |
dfeec247 XL |
213 | found struct `Struct` |
214 | = note: for more on the distinction between the stack and the heap, read https://doc.rust-lang.org/book/ch15-01-box.html, https://doc.rust-lang.org/rust-by-example/std/box.html, and https://doc.rust-lang.org/std/boxed/index.html | |
215 | ||
216 | error[E0308]: mismatched types | |
217 | --> $DIR/dyn-trait-return-should-be-impl-trait.rs:48:9 | |
218 | | | |
219 | LL | fn baz() -> Box<dyn Trait> { | |
1b1a35ee | 220 | | -------------- expected `Box<(dyn Trait + 'static)>` because of return type |
dfeec247 XL |
221 | ... |
222 | LL | 42 | |
223 | | ^^ | |
224 | | | | |
1b1a35ee | 225 | | expected struct `Box`, found integer |
dfeec247 XL |
226 | | help: store this in the heap by calling `Box::new`: `Box::new(42)` |
227 | | | |
1b1a35ee | 228 | = note: expected struct `Box<(dyn Trait + 'static)>` |
dfeec247 XL |
229 | found type `{integer}` |
230 | = note: for more on the distinction between the stack and the heap, read https://doc.rust-lang.org/book/ch15-01-box.html, https://doc.rust-lang.org/rust-by-example/std/box.html, and https://doc.rust-lang.org/std/boxed/index.html | |
231 | ||
232 | error[E0308]: mismatched types | |
233 | --> $DIR/dyn-trait-return-should-be-impl-trait.rs:53:9 | |
234 | | | |
235 | LL | fn baw() -> Box<dyn Trait> { | |
1b1a35ee | 236 | | -------------- expected `Box<(dyn Trait + 'static)>` because of return type |
dfeec247 XL |
237 | LL | if true { |
238 | LL | 0 | |
239 | | ^ | |
240 | | | | |
1b1a35ee | 241 | | expected struct `Box`, found integer |
dfeec247 XL |
242 | | help: store this in the heap by calling `Box::new`: `Box::new(0)` |
243 | | | |
1b1a35ee | 244 | = note: expected struct `Box<(dyn Trait + 'static)>` |
dfeec247 XL |
245 | found type `{integer}` |
246 | = note: for more on the distinction between the stack and the heap, read https://doc.rust-lang.org/book/ch15-01-box.html, https://doc.rust-lang.org/rust-by-example/std/box.html, and https://doc.rust-lang.org/std/boxed/index.html | |
247 | ||
248 | error[E0308]: mismatched types | |
249 | --> $DIR/dyn-trait-return-should-be-impl-trait.rs:55:9 | |
250 | | | |
251 | LL | fn baw() -> Box<dyn Trait> { | |
1b1a35ee | 252 | | -------------- expected `Box<(dyn Trait + 'static)>` because of return type |
dfeec247 XL |
253 | ... |
254 | LL | 42 | |
255 | | ^^ | |
256 | | | | |
1b1a35ee | 257 | | expected struct `Box`, found integer |
dfeec247 XL |
258 | | help: store this in the heap by calling `Box::new`: `Box::new(42)` |
259 | | | |
1b1a35ee | 260 | = note: expected struct `Box<(dyn Trait + 'static)>` |
dfeec247 XL |
261 | found type `{integer}` |
262 | = note: for more on the distinction between the stack and the heap, read https://doc.rust-lang.org/book/ch15-01-box.html, https://doc.rust-lang.org/rust-by-example/std/box.html, and https://doc.rust-lang.org/std/boxed/index.html | |
263 | ||
264 | error[E0746]: return type cannot have an unboxed trait object | |
265 | --> $DIR/dyn-trait-return-should-be-impl-trait.rs:60:13 | |
266 | | | |
267 | LL | fn bat() -> dyn Trait { | |
268 | | ^^^^^^^^^ doesn't have a size known at compile-time | |
269 | | | |
270 | = note: for information on `impl Trait`, see <https://doc.rust-lang.org/book/ch10-02-traits.html#returning-types-that-implement-traits> | |
f9f354fc | 271 | help: use `impl Trait` as the return type, as all return paths are of type `{integer}`, which implements `Trait` |
dfeec247 XL |
272 | | |
273 | LL | fn bat() -> impl Trait { | |
274 | | ^^^^^^^^^^ | |
275 | ||
276 | error[E0746]: return type cannot have an unboxed trait object | |
277 | --> $DIR/dyn-trait-return-should-be-impl-trait.rs:66:13 | |
278 | | | |
279 | LL | fn bay() -> dyn Trait { | |
280 | | ^^^^^^^^^ doesn't have a size known at compile-time | |
281 | | | |
282 | = note: for information on `impl Trait`, see <https://doc.rust-lang.org/book/ch10-02-traits.html#returning-types-that-implement-traits> | |
f9f354fc | 283 | help: use `impl Trait` as the return type, as all return paths are of type `{integer}`, which implements `Trait` |
dfeec247 XL |
284 | | |
285 | LL | fn bay() -> impl Trait { | |
286 | | ^^^^^^^^^^ | |
287 | ||
f9f354fc | 288 | error: aborting due to 20 previous errors |
dfeec247 XL |
289 | |
290 | Some errors have detailed explanations: E0277, E0308, E0746. | |
291 | For more information about an error, try `rustc --explain E0277`. |