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Better account for more cases involving closures

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This commit is contained in:
Esteban Küber 2024-04-12 04:46:31 +00:00
parent 3cdc6897c5
commit dea9b5031c
14 changed files with 137 additions and 31 deletions
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50
compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
View File

@ -203,13 +203,7 @@ pub(crate) fn report_use_of_moved_or_uninitialized(
if !seen_spans.contains(&move_span) {
if !closure {
self.suggest_ref_or_clone(
mpi,
move_span,
&mut err,
&mut in_pattern,
move_spans,
);
self.suggest_ref_or_clone(mpi, &mut err, &mut in_pattern, move_spans);
}
let msg_opt = CapturedMessageOpt {
@ -351,18 +345,28 @@ pub(crate) fn report_use_of_moved_or_uninitialized(
fn suggest_ref_or_clone(
&self,
mpi: MovePathIndex,
move_span: Span,
err: &mut Diag<'tcx>,
in_pattern: &mut bool,
move_spans: UseSpans<'_>,
) {
let move_span = match move_spans {
UseSpans::ClosureUse { capture_kind_span, .. } => capture_kind_span,
_ => move_spans.args_or_use(),
};
struct ExpressionFinder<'hir> {
expr_span: Span,
expr: Option<&'hir hir::Expr<'hir>>,
pat: Option<&'hir hir::Pat<'hir>>,
parent_pat: Option<&'hir hir::Pat<'hir>>,
hir: rustc_middle::hir::map::Map<'hir>,
}
impl<'hir> Visitor<'hir> for ExpressionFinder<'hir> {
type NestedFilter = OnlyBodies;
fn nested_visit_map(&mut self) -> Self::Map {
self.hir
}
fn visit_expr(&mut self, e: &'hir hir::Expr<'hir>) {
if e.span == self.expr_span {
self.expr = Some(e);
@ -397,8 +401,13 @@ fn visit_pat(&mut self, p: &'hir hir::Pat<'hir>) {
let expr = hir.body(body_id).value;
let place = &self.move_data.move_paths[mpi].place;
let span = place.as_local().map(|local| self.body.local_decls[local].source_info.span);
let mut finder =
ExpressionFinder { expr_span: move_span, expr: None, pat: None, parent_pat: None };
let mut finder = ExpressionFinder {
expr_span: move_span,
expr: None,
pat: None,
parent_pat: None,
hir,
};
finder.visit_expr(expr);
if let Some(span) = span
&& let Some(expr) = finder.expr
@ -479,12 +488,10 @@ fn visit_pat(&mut self, p: &'hir hir::Pat<'hir>) {
} else if let UseSpans::ClosureUse {
closure_kind:
ClosureKind::Coroutine(CoroutineKind::Desugared(_, CoroutineSource::Block)),
args_span: _,
capture_kind_span: _,
path_span,
..
} = move_spans
{
self.suggest_cloning(err, ty, expr, path_span);
self.suggest_cloning(err, ty, expr, None);
} else if self.suggest_hoisting_call_outside_loop(err, expr) {
// The place where the the type moves would be misleading to suggest clone.
// #121466
@ -1233,6 +1240,18 @@ pub(crate) fn clone_on_reference(&self, expr: &hir::Expr<'_>) -> Option<Span> {
}
}
fn in_move_closure(&self, expr: &hir::Expr<'_>) -> bool {
for (_, node) in self.infcx.tcx.hir().parent_iter(expr.hir_id) {
if let hir::Node::Expr(hir::Expr { kind: hir::ExprKind::Closure(closure), .. }) = node
&& let hir::CaptureBy::Value { .. } = closure.capture_clause
{
// `move || x.clone()` will not work. FIXME: suggest `let y = x.clone(); move || y`
return true;
}
}
false
}
fn suggest_cloning_inner(
&self,
err: &mut Diag<'_>,
@ -1245,6 +1264,9 @@ fn suggest_cloning_inner(
// See `tests/ui/moves/needs-clone-through-deref.rs`
return false;
}
if self.in_move_closure(expr) {
return false;
}
// Try to find predicates on *generic params* that would allow copying `ty`
let suggestion =
if let Some(symbol) = tcx.hir().maybe_get_struct_pattern_shorthand_field(expr) {

11
tests/ui/borrowck/borrowck-closures-slice-patterns.stderr
View File

@ -38,6 +38,11 @@ LL | let [y, z @ ..] = x;
LL | };
LL | &x;
| ^^ value borrowed here after move
|
help: consider cloning the value if the performance cost is acceptable
|
LL | let [y, z @ ..] = x.clone();
| ++++++++
error[E0502]: cannot borrow `*x` as mutable because it is also borrowed as immutable
--> $DIR/borrowck-closures-slice-patterns.rs:33:13
@ -79,6 +84,12 @@ LL | let [y, z @ ..] = *x;
LL | };
LL | &x;
| ^^ value borrowed here after move
|
help: consider cloning the value if the performance cost is acceptable
|
LL - let [y, z @ ..] = *x;
LL + let [y, z @ ..] = x.clone();
|
error[E0502]: cannot borrow `*x` as mutable because it is also borrowed as immutable
--> $DIR/borrowck-closures-slice-patterns.rs:59:13

14
tests/ui/borrowck/issue-101119.stderr
View File

@ -4,11 +4,25 @@ error[E0382]: use of moved value: `state`
LL | fn fill_memory_blocks_mt(state: &mut State) {
| ----- move occurs because `state` has type `&mut State`, which does not implement the `Copy` trait
LL | loop {
| ---- inside of this loop
LL | once(move || {
| ^^^^^^^ value moved into closure here, in previous iteration of loop
LL |
LL | fill_segment(state);
| ----- use occurs due to use in closure
|
note: consider changing this parameter type in function `fill_segment` to borrow instead if owning the value isn't necessary
--> $DIR/issue-101119.rs:14:20
|
LL | fn fill_segment(_: &mut State) {}
| ------------ ^^^^^^^^^^ this parameter takes ownership of the value
| |
| in this function
note: if `State` implemented `Clone`, you could clone the value
--> $DIR/issue-101119.rs:1:1
|
LL | struct State;
| ^^^^^^^^^^^^
error: aborting due to 1 previous error

2
tests/ui/issues/issue-24357.rs
View File

@ -1,4 +1,4 @@
struct NoCopy;
struct NoCopy; //~ NOTE if `NoCopy` implemented `Clone`, you could clone the value
fn main() {
let x = NoCopy;
//~^ NOTE move occurs because `x` has type `NoCopy`

6
tests/ui/issues/issue-24357.stderr
View File

@ -11,6 +11,12 @@ LL | let f = move || { let y = x; };
...
LL | let z = x;
| ^ value used here after move
|
note: if `NoCopy` implemented `Clone`, you could clone the value
--> $DIR/issue-24357.rs:1:1
|
LL | struct NoCopy;
| ^^^^^^^^^^^^^
error: aborting due to 1 previous error

7
tests/ui/moves/issue-75904-move-closure-loop.stderr
View File

@ -4,11 +4,18 @@ error[E0382]: use of moved value: `a`
LL | let mut a = NotCopy;
| ----- move occurs because `a` has type `NotCopy`, which does not implement the `Copy` trait
LL | loop {
| ---- inside of this loop
LL | || {
| ^^ value moved into closure here, in previous iteration of loop
LL | &mut a;
LL | a;
| - use occurs due to use in closure
|
note: if `NotCopy` implemented `Clone`, you could clone the value
--> $DIR/issue-75904-move-closure-loop.rs:5:1
|
LL | struct NotCopy;
| ^^^^^^^^^^^^^^
error: aborting due to 1 previous error

2
tests/ui/moves/moves-based-on-type-capture-clause-bad.stderr
View File

@ -4,7 +4,7 @@ error[E0382]: borrow of moved value: `x`
LL | let x = "Hello world!".to_string();
| - move occurs because `x` has type `String`, which does not implement the `Copy` trait
LL | thread::spawn(move || {
| ------ value moved into closure here
| ------- value moved into closure here
LL | println!("{}", x);
| - variable moved due to use in closure
LL | });

23
tests/ui/nll/closure-move-spans.fixed Normal file
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@ -0,0 +1,23 @@
// check that moves due to a closure capture give a special note
//@ run-rustfix
#![allow(unused_variables, unused_must_use, dead_code)]
fn move_after_move(x: String) {
|| x.clone();
let y = x; //~ ERROR
}
fn borrow_after_move(x: String) {
|| x.clone();
let y = &x; //~ ERROR
}
fn borrow_mut_after_move(mut x: String) {
|| x.clone();
let y = &mut x; //~ ERROR
}
fn fn_ref<F: Fn()>(f: F) -> F { f }
fn fn_mut<F: FnMut()>(f: F) -> F { f }
fn main() {}

2
tests/ui/nll/closure-move-spans.rs
View File

@ -1,4 +1,6 @@
// check that moves due to a closure capture give a special note
//@ run-rustfix
#![allow(unused_variables, unused_must_use, dead_code)]
fn move_after_move(x: String) {
|| x;

21
tests/ui/nll/closure-move-spans.stderr
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@ -1,5 +1,5 @@
error[E0382]: use of moved value: `x`
--> $DIR/closure-move-spans.rs:5:13
--> $DIR/closure-move-spans.rs:7:13
|
LL | fn move_after_move(x: String) {
| - move occurs because `x` has type `String`, which does not implement the `Copy` trait
@ -9,9 +9,14 @@ LL | || x;
| value moved into closure here
LL | let y = x;
| ^ value used here after move
|
help: consider cloning the value if the performance cost is acceptable
|
LL | || x.clone();
| ++++++++
error[E0382]: borrow of moved value: `x`
--> $DIR/closure-move-spans.rs:10:13
--> $DIR/closure-move-spans.rs:12:13
|
LL | fn borrow_after_move(x: String) {
| - move occurs because `x` has type `String`, which does not implement the `Copy` trait
@ -21,9 +26,14 @@ LL | || x;
| value moved into closure here
LL | let y = &x;
| ^^ value borrowed here after move
|
help: consider cloning the value if the performance cost is acceptable
|
LL | || x.clone();
| ++++++++
error[E0382]: borrow of moved value: `x`
--> $DIR/closure-move-spans.rs:15:13
--> $DIR/closure-move-spans.rs:17:13
|
LL | fn borrow_mut_after_move(mut x: String) {
| ----- move occurs because `x` has type `String`, which does not implement the `Copy` trait
@ -33,6 +43,11 @@ LL | || x;
| value moved into closure here
LL | let y = &mut x;
| ^^^^^^ value borrowed here after move
|
help: consider cloning the value if the performance cost is acceptable
|
LL | || x.clone();
| ++++++++
error: aborting due to 3 previous errors

6
tests/ui/nll/closures-in-loops.stderr
View File

@ -4,10 +4,16 @@ error[E0382]: use of moved value: `x`
LL | fn repreated_move(x: String) {
| - move occurs because `x` has type `String`, which does not implement the `Copy` trait
LL | for i in 0..10 {
| -------------- inside of this loop
LL | || x;
| ^^ - use occurs due to use in closure
| |
| value moved into closure here, in previous iteration of loop
|
help: consider cloning the value if the performance cost is acceptable
|
LL | || x.clone();
| ++++++++
error[E0499]: cannot borrow `x` as mutable more than once at a time
--> $DIR/closures-in-loops.rs:13:16

10
tests/ui/nll/issue-27282-move-match-input-into-guard.stderr
View File

@ -10,6 +10,11 @@ LL | _ if { (|| { let bar = b; *bar = false; })();
| -- - variable moved due to use in closure
| |
| value moved into closure here
|
help: consider cloning the value if the performance cost is acceptable
|
LL | _ if { (|| { let bar = b.clone(); *bar = false; })();
| ++++++++
error[E0382]: use of moved value: `b`
--> $DIR/issue-27282-move-match-input-into-guard.rs:24:5
@ -23,6 +28,11 @@ LL | (|| { let bar = b; *bar = false; })();
| -- - variable moved due to use in closure
| |
| value moved into closure here
|
help: consider cloning the value if the performance cost is acceptable
|
LL | (|| { let bar = b.clone(); *bar = false; })();
| ++++++++
error: aborting due to 2 previous errors

10
tests/ui/unboxed-closures/unboxed-closure-illegal-move.stderr
View File

@ -37,11 +37,6 @@ LL | let f = to_fn(move || drop(x));
| ------- ^ move occurs because `x` has type `Box<i32>`, which does not implement the `Copy` trait
| |
| captured by this `Fn` closure
|
help: consider cloning the value if the performance cost is acceptable
|
LL | let f = to_fn(move || drop(x.clone()));
| ++++++++
error[E0507]: cannot move out of `x`, a captured variable in an `FnMut` closure
--> $DIR/unboxed-closure-illegal-move.rs:32:40
@ -52,11 +47,6 @@ LL | let f = to_fn_mut(move || drop(x));
| ------- ^ move occurs because `x` has type `Box<i32>`, which does not implement the `Copy` trait
| |
| captured by this `FnMut` closure
|
help: consider cloning the value if the performance cost is acceptable
|
LL | let f = to_fn_mut(move || drop(x.clone()));
| ++++++++
error: aborting due to 4 previous errors