Closed
Description
openedon Jun 23, 2024
Code
fn main() {
let val = String::from("test");
let p = std::ptr::addr_of!(val);
unsafe {
let inner: String = *p;
dbg!(inner);
std::mem::forget(val);
}
}Current output
error[E0507]: cannot move out of `*p` which is behind a raw pointer
--> src/main.rs:5:29
|
5 | let inner: String = *p;
| ^^ move occurs because `*p` has type `String`, which does not implement the `Copy` trait
|
help: consider removing the dereference here
|
5 - let inner: String = *p;
5 + let inner: String = p;
|
help: consider cloning the value if the performance cost is acceptable
|
5 - let inner: String = *p;
5 + let inner: String = p.clone();
|
For more information about this error, try `rustc --explain E0507`.Desired output
error[E0507]: cannot move out of `*p` which is behind a raw pointer
--> src/main.rs:5:29
|
5 | let inner: String = *p;
| ^^ move occurs because `*p` has type `String`, which does not implement the `Copy` trait
|
help: consider using `ptr::read` to get the value the pointer refers to
|
5 - let inner: String = *p;
5 + let inner: String = p.read();
|
For more information about this error, try `rustc --explain E0507`.Rationale and extra context
Cloning the pointer doesn't make sense in that situation and would cause a type mismatch error. I'm not sure whether any of the two current suggestions should be kept or removed in this case.
Other cases
No response
Rust Version
rustc 1.79.0 (129f3b996 2024-06-10)
binary: rustc
commit-hash: 129f3b9964af4d4a709d1383930ade12dfe7c081
commit-date: 2024-06-10
host: x86_64-unknown-linux-gnu
release: 1.79.0
LLVM version: 18.1.7Anything else?
No response
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Area: Messages for errors, warnings, and lintsArea: Messages for errors, warnings, and lintsDiagnostics: An error or lint that needs small tweaks.Diagnostics: An error or lint that needs small tweaks.Relevant to the compiler team, which will review and decide on the PR/issue.Relevant to the compiler team, which will review and decide on the PR/issue.