2024-02-16 14:02:50 -06:00
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//@ run-rustfix
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Suggest cloning and point out obligation errors on move error
When encountering a move error, look for implementations of `Clone` for
the moved type. If there is one, check if all its obligations are met.
If they are, we suggest cloning without caveats. If they aren't, we
suggest cloning while mentioning the unmet obligations, potentially
suggesting `#[derive(Clone)]` when appropriate.
```
error[E0507]: cannot move out of a shared reference
--> $DIR/suggest-clone-when-some-obligation-is-unmet.rs:20:28
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LL | let mut copy: Vec<U> = map.clone().into_values().collect();
| ^^^^^^^^^^^ ------------- value moved due to this method call
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| move occurs because value has type `HashMap<T, U, Hash128_1>`, which does not implement the `Copy` trait
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note: `HashMap::<K, V, S>::into_values` takes ownership of the receiver `self`, which moves value
--> $SRC_DIR/std/src/collections/hash/map.rs:LL:COL
help: you could `clone` the value and consume it, if the `Hash128_1: Clone` trait bound could be satisfied
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LL | let mut copy: Vec<U> = <HashMap<T, U, Hash128_1> as Clone>::clone(&map.clone()).into_values().collect();
| ++++++++++++++++++++++++++++++++++++++++++++ +
help: consider annotating `Hash128_1` with `#[derive(Clone)]`
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LL + #[derive(Clone)]
LL | pub struct Hash128_1;
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```
Fix #109429.
2023-11-20 16:51:52 -06:00
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// Issue #109429
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use std::collections::hash_map::DefaultHasher;
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use std::collections::HashMap;
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use std::hash::BuildHasher;
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use std::hash::Hash;
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#[derive(Clone)]
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pub struct Hash128_1;
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impl BuildHasher for Hash128_1 {
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type Hasher = DefaultHasher;
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fn build_hasher(&self) -> DefaultHasher { DefaultHasher::default() }
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}
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#[allow(unused)]
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pub fn hashmap_copy<T, U>(
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map: &HashMap<T, U, Hash128_1>,
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) where T: Hash + Clone, U: Clone
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{
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let mut copy: Vec<U> = <HashMap<T, U, Hash128_1> as Clone>::clone(&map.clone()).into_values().collect(); //~ ERROR
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}
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pub fn make_map() -> HashMap<String, i64, Hash128_1>
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{
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HashMap::with_hasher(Hash128_1)
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}
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fn main() {}
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