bjoernager/rust
bjoernager/rust
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Suggest cloning captured binding in move closure

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```
error[E0507]: cannot move out of `bar`, a captured variable in an `FnMut` closure
  --> $DIR/borrowck-move-by-capture.rs:9:29
   |
LL |     let bar: Box<_> = Box::new(3);
   |         --- captured outer variable
LL |     let _g = to_fn_mut(|| {
   |                        -- captured by this `FnMut` closure
LL |         let _h = to_fn_once(move || -> isize { *bar });
   |                             ^^^^^^^^^^^^^^^^   ----
   |                             |                  |
   |                             |                  variable moved due to use in closure
   |                             |                  move occurs because `bar` has type `Box<isize>`, which does not implement the `Copy` trait
   |                             `bar` is moved here
   |
help: clone the value before moving it into the closure
   |
LL ~         let value = bar.clone();
LL ~         let _h = to_fn_once(move || -> isize { value });
   |
```
This commit is contained in:
Esteban Küber 2024-04-19 04:26:42 +00:00
parent d68f2a6b71
commit ad9a5a5f9f
8 changed files with 267 additions and 22 deletions
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11
compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
View file

@ -50,12 +50,13 @@ pub struct FindExprBySpan<'hir> {
pub span: Span,
pub result: Option<&'hir hir::Expr<'hir>>,
pub ty_result: Option<&'hir hir::Ty<'hir>>,
pub include_closures: bool,
pub tcx: TyCtxt<'hir>,
}
impl<'hir> FindExprBySpan<'hir> {
pub fn new(span: Span, tcx: TyCtxt<'hir>) -> Self {
Self { span, result: None, ty_result: None, tcx }
Self { span, result: None, ty_result: None, tcx, include_closures: false }
}
}
@ -70,9 +71,17 @@ impl<'v> Visitor<'v> for FindExprBySpan<'v> {
if self.span == ex.span {
self.result = Some(ex);
} else {
if let hir::ExprKind::Closure(..) = ex.kind
&& self.include_closures
&& let closure_header_sp = self.span.with_hi(ex.span.hi())
&& closure_header_sp == ex.span
{
self.result = Some(ex);
}
hir::intravisit::walk_expr(self, ex);
}
}
fn visit_ty(&mut self, ty: &'v hir::Ty<'v>) {
if self.span == ty.span {
self.ty_result = Some(ty);