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Rollup merge of #100186 - compiler-errors:or-as_mut, r=fee1-dead

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Mention `as_mut` alongside `as_ref` in borrowck error message

Kinda fixes #99426 but I guess that really might be better staying open to see if we could make it suggest `as_mut` in a structured way. Not sure how to change borrowck to know that info tho.
This commit is contained in:
Matthias Krüger 2022-08-20 07:08:57 +02:00 committed by GitHub
commit 3cca14093a
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8 changed files with 15 additions and 84 deletions
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14
compiler/rustc_borrowck/src/diagnostics/mod.rs
View File

@ -1086,14 +1086,6 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
),
);
}
if is_option_or_result && maybe_reinitialized_locations_is_empty {
err.span_suggestion_verbose(
fn_call_span.shrink_to_lo(),
"consider calling `.as_ref()` to borrow the type's contents",
"as_ref().",
Applicability::MachineApplicable,
);
}
// Avoid pointing to the same function in multiple different
// error messages.
if span != DUMMY_SP && self.fn_self_span_reported.insert(self_arg.span) {
@ -1102,6 +1094,12 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
&format!("this function takes ownership of the receiver `self`, which moves {}", place_name)
);
}
if is_option_or_result && maybe_reinitialized_locations_is_empty {
err.span_label(
var_span,
"help: consider calling `.as_ref()` or `.as_mut()` to borrow the type's contents",
);
}
}
// Other desugarings takes &self, which cannot cause a move
_ => {}

5
src/test/ui/borrowck/suggest-as-ref-on-mut-closure.stderr
View File

@ -5,6 +5,7 @@ LL | cb.map(|cb| cb());
| ^^^--------------
| | |
| | `*cb` moved due to this method call
| help: consider calling `.as_ref()` or `.as_mut()` to borrow the type's contents
| move occurs because `*cb` has type `Option<&mut dyn FnMut()>`, which does not implement the `Copy` trait
|
note: this function takes ownership of the receiver `self`, which moves `*cb`
@ -12,10 +13,6 @@ note: this function takes ownership of the receiver `self`, which moves `*cb`
|
LL | pub const fn map<U, F>(self, f: F) -> Option<U>
| ^^^^
help: consider calling `.as_ref()` to borrow the type's contents
|
LL | cb.as_ref().map(|cb| cb());
| +++++++++
error[E0596]: cannot borrow `*cb` as mutable, as it is behind a `&` reference
--> $DIR/suggest-as-ref-on-mut-closure.rs:12:26

13
src/test/ui/suggestions/as-ref-2.fixed
View File

@ -1,13 +0,0 @@
// run-rustfix
struct Struct;
fn bar(_: &Struct) -> Struct {
Struct
}
fn main() {
let foo = Some(Struct);
let _x: Option<Struct> = foo.as_ref().map(|s| bar(&s));
let _y = foo; //~ERROR use of moved value: `foo`
}

2
src/test/ui/suggestions/as-ref-2.rs
View File

@ -1,5 +1,3 @@
// run-rustfix
struct Struct;
fn bar(_: &Struct) -> Struct {

10
src/test/ui/suggestions/as-ref-2.stderr
View File

@ -1,10 +1,12 @@
error[E0382]: use of moved value: `foo`
--> $DIR/as-ref-2.rs:12:14
--> $DIR/as-ref-2.rs:10:14
|
LL | let foo = Some(Struct);
| --- move occurs because `foo` has type `Option<Struct>`, which does not implement the `Copy` trait
LL | let _x: Option<Struct> = foo.map(|s| bar(&s));
| ---------------- `foo` moved due to this method call
| --- ---------------- `foo` moved due to this method call
| |
| help: consider calling `.as_ref()` or `.as_mut()` to borrow the type's contents
LL | let _y = foo;
| ^^^ value used here after move
|
@ -13,10 +15,6 @@ note: this function takes ownership of the receiver `self`, which moves `foo`
|
LL | pub const fn map<U, F>(self, f: F) -> Option<U>
| ^^^^
help: consider calling `.as_ref()` to borrow the type's contents
|
LL | let _x: Option<Struct> = foo.as_ref().map(|s| bar(&s));
| +++++++++
error: aborting due to previous error

39
src/test/ui/suggestions/option-content-move.fixed
View File

@ -1,39 +0,0 @@
//run-rustfix
pub struct LipogramCorpora {
selections: Vec<(char, Option<String>)>,
}
impl LipogramCorpora {
pub fn validate_all(&mut self) -> Result<(), char> {
for selection in &self.selections {
if selection.1.is_some() {
if selection.1.as_ref().unwrap().contains(selection.0) {
//~^ ERROR cannot move out of `selection.1`
return Err(selection.0);
}
}
}
Ok(())
}
}
pub struct LipogramCorpora2 {
selections: Vec<(char, Result<String, String>)>,
}
impl LipogramCorpora2 {
pub fn validate_all(&mut self) -> Result<(), char> {
for selection in &self.selections {
if selection.1.is_ok() {
if selection.1.as_ref().unwrap().contains(selection.0) {
//~^ ERROR cannot move out of `selection.1`
return Err(selection.0);
}
}
}
Ok(())
}
}
fn main() {}

2
src/test/ui/suggestions/option-content-move.rs
View File

@ -1,5 +1,3 @@
//run-rustfix
pub struct LipogramCorpora {
selections: Vec<(char, Option<String>)>,
}

14
src/test/ui/suggestions/option-content-move.stderr
View File

@ -1,9 +1,10 @@
error[E0507]: cannot move out of `selection.1` which is behind a shared reference
--> $DIR/option-content-move.rs:11:20
--> $DIR/option-content-move.rs:9:20
|
LL | if selection.1.unwrap().contains(selection.0) {
| ^^^^^^^^^^^ -------- `selection.1` moved due to this method call
| |
| help: consider calling `.as_ref()` or `.as_mut()` to borrow the type's contents
| move occurs because `selection.1` has type `Option<String>`, which does not implement the `Copy` trait
|
note: this function takes ownership of the receiver `self`, which moves `selection.1`
@ -11,17 +12,14 @@ note: this function takes ownership of the receiver `self`, which moves `selecti
|
LL | pub const fn unwrap(self) -> T {
| ^^^^
help: consider calling `.as_ref()` to borrow the type's contents
|
LL | if selection.1.as_ref().unwrap().contains(selection.0) {
| +++++++++
error[E0507]: cannot move out of `selection.1` which is behind a shared reference
--> $DIR/option-content-move.rs:29:20
--> $DIR/option-content-move.rs:27:20
|
LL | if selection.1.unwrap().contains(selection.0) {
| ^^^^^^^^^^^ -------- `selection.1` moved due to this method call
| |
| help: consider calling `.as_ref()` or `.as_mut()` to borrow the type's contents
| move occurs because `selection.1` has type `Result<String, String>`, which does not implement the `Copy` trait
|
note: this function takes ownership of the receiver `self`, which moves `selection.1`
@ -29,10 +27,6 @@ note: this function takes ownership of the receiver `self`, which moves `selecti
|
LL | pub fn unwrap(self) -> T
| ^^^^
help: consider calling `.as_ref()` to borrow the type's contents
|
LL | if selection.1.as_ref().unwrap().contains(selection.0) {
| +++++++++
error: aborting due to 2 previous errors