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Suggest using std::mem::drop function instead of explicit destructor …
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stanislav-tkach committed May 21, 2020
1 parent 672b272 commit 34b5118
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Showing 7 changed files with 45 additions and 12 deletions.
26 changes: 22 additions & 4 deletions src/librustc_typeck/check/callee.rs
Original file line number Diff line number Diff line change
Expand Up @@ -21,11 +21,29 @@ use rustc_target::spec::abi;
/// Checks that it is legal to call methods of the trait corresponding
/// to `trait_id` (this only cares about the trait, not the specific
/// method that is called).
pub fn check_legal_trait_for_method_call(tcx: TyCtxt<'_>, span: Span, trait_id: DefId) {
pub fn check_legal_trait_for_method_call(
tcx: TyCtxt<'_>,
span: Span,
receiver: Option<Span>,
trait_id: DefId,
) {
if tcx.lang_items().drop_trait() == Some(trait_id) {
struct_span_err!(tcx.sess, span, E0040, "explicit use of destructor method")
.span_label(span, "explicit destructor calls not allowed")
.emit();
let mut err = struct_span_err!(tcx.sess, span, E0040, "explicit use of destructor method");
err.span_label(span, "explicit destructor calls not allowed");

let snippet = receiver
.and_then(|s| tcx.sess.source_map().span_to_snippet(s).ok())
.unwrap_or_default();

let (suggestion, applicability) = if snippet.is_empty() {
(snippet, Applicability::Unspecified)
} else {
(format!("drop({})", snippet), Applicability::MachineApplicable)
};

err.span_suggestion(span, "consider using `drop` function", suggestion, applicability);

err.emit();
}
}

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9 changes: 6 additions & 3 deletions src/librustc_typeck/check/method/confirm.rs
Original file line number Diff line number Diff line change
Expand Up @@ -597,9 +597,12 @@ impl<'a, 'tcx> ConfirmContext<'a, 'tcx> {
fn enforce_illegal_method_limitations(&self, pick: &probe::Pick<'_>) {
// Disallow calls to the method `drop` defined in the `Drop` trait.
match pick.item.container {
ty::TraitContainer(trait_def_id) => {
callee::check_legal_trait_for_method_call(self.tcx, self.span, trait_def_id)
}
ty::TraitContainer(trait_def_id) => callee::check_legal_trait_for_method_call(
self.tcx,
self.span,
Some(self.self_expr.span),
trait_def_id,
),
ty::ImplContainer(..) => {}
}
}
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2 changes: 1 addition & 1 deletion src/librustc_typeck/check/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -5438,7 +5438,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
debug!("instantiate_value_path: def_id={:?} container={:?}", def_id, container);
match container {
ty::TraitContainer(trait_did) => {
callee::check_legal_trait_for_method_call(tcx, span, trait_did)
callee::check_legal_trait_for_method_call(tcx, span, None, trait_did)
}
ty::ImplContainer(impl_def_id) => {
if segments.len() == 1 {
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5 changes: 4 additions & 1 deletion src/test/ui/error-codes/E0040.stderr
Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,10 @@ error[E0040]: explicit use of destructor method
--> $DIR/E0040.rs:13:7
|
LL | x.drop();
| ^^^^ explicit destructor calls not allowed
| ^^^^
| |
| explicit destructor calls not allowed
| help: consider using `drop` function: `drop(x)`

error: aborting due to previous error

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5 changes: 4 additions & 1 deletion src/test/ui/explicit/explicit-call-to-dtor.stderr
Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,10 @@ error[E0040]: explicit use of destructor method
--> $DIR/explicit-call-to-dtor.rs:13:7
|
LL | x.drop();
| ^^^^ explicit destructor calls not allowed
| ^^^^
| |
| explicit destructor calls not allowed
| help: consider using `drop` function: `drop(x)`

error: aborting due to previous error

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5 changes: 4 additions & 1 deletion src/test/ui/explicit/explicit-call-to-supertrait-dtor.stderr
Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,10 @@ error[E0040]: explicit use of destructor method
--> $DIR/explicit-call-to-supertrait-dtor.rs:17:14
|
LL | self.drop();
| ^^^^ explicit destructor calls not allowed
| ^^^^
| |
| explicit destructor calls not allowed
| help: consider using `drop` function: `drop(self)`

error: aborting due to previous error

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5 changes: 4 additions & 1 deletion src/test/ui/illegal-ufcs-drop.stderr
Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,10 @@ error[E0040]: explicit use of destructor method
--> $DIR/illegal-ufcs-drop.rs:8:5
|
LL | Drop::drop(&mut Foo)
| ^^^^^^^^^^ explicit destructor calls not allowed
| ^^^^^^^^^^
| |
| explicit destructor calls not allowed
| help: consider using `drop` function

error: aborting due to previous error

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