Bad diagnostics using ? operator on Option<Cow<'_, str>> [E507] #116335
Description
Code
use std::borrow::Cow;
struct Foo<'a> {
list: Vec<Bar<'a>>,
}
impl<'a> Foo<'a> {
fn bar(&self) -> Option<String> {
Some(self.list.first()?.inner?.into_owned())
}
}
struct Bar<'a> {
inner: Option<Cow<'a, str>>,
}Current output
error[E0507]: cannot move out of a shared reference
--> src/lib.rs:9:14
|
9 | Some(self.list.first()?.inner?.into_owned())
| ^^^^^^^^^^^^^^^^^^^^^^^^-
| |
| value moved due to this method call
| move occurs because value has type `Option<Cow<'_, str>>`, which does not implement the `Copy` trait
|
note: `branch` takes ownership of the receiver `self`, which moves value
--> /rustc/d5c2e9c342b358556da91d61ed4133f6f50fc0c3/library/core/src/ops/try_trait.rs:217:15
help: you can `clone` the value and consume it, but this might not be your desired behavior
|
9 | Some(clone().self.list.first()?.inner?.into_owned())
| ++++++++
For more information about this error, try `rustc --explain E0507`.Desired output
No response
Rationale and extra context
Pointing to some anonymous branch() method from (what I presume is) an impl for Try feels very unhelpful here. Note also the strange suggestion which wants me to add a bare clone() call before the expression...
Other cases
No response
Anything else?
No response