mikros/rust
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Rollup merge of #62228 - varkor:must_use-trait-in-box, r=Centril

Browse Source 
Extend the #[must_use] lint to boxed types

Fixes https://github.com/rust-lang/rust/issues/55506#issuecomment-506940181 (cc @Nemo157).

This should have been included as part of https://github.com/rust-lang/rust/pull/55663, but was overlooked.
This commit is contained in:
Mazdak Farrokhzad 2019-06-30 21:57:27 +02:00 committed by GitHub
commit c779f4e89c
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
7 changed files with 67 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
src/librustc_lint/unused.rs
View File

@ -48,7 +48,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedResults {
}
let ty = cx.tables.expr_ty(&expr);
let type_permits_lack_of_use = check_must_use_ty(cx, ty, &expr, s.span, "");
let type_permits_lack_of_use = check_must_use_ty(cx, ty, &expr, s.span, "", "");
let mut fn_warned = false;
let mut op_warned = false;
@ -133,6 +133,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedResults {
ty: Ty<'tcx>,
expr: &hir::Expr,
span: Span,
descr_pre_path: &str,
descr_post_path: &str,
) -> bool {
if ty.is_unit() || cx.tcx.is_ty_uninhabited_from(
@ -142,14 +143,22 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedResults {
}
match ty.sty {
ty::Adt(def, _) => check_must_use_def(cx, def.did, span, "", descr_post_path),
ty::Adt(..) if ty.is_box() => {
let boxed_ty = ty.boxed_ty();
let descr_pre_path = &format!("{}boxed ", descr_pre_path);
check_must_use_ty(cx, boxed_ty, expr, span, descr_pre_path, descr_post_path)
}
ty::Adt(def, _) => {
check_must_use_def(cx, def.did, span, descr_pre_path, descr_post_path)
}
ty::Opaque(def, _) => {
let mut has_emitted = false;
for (predicate, _) in &cx.tcx.predicates_of(def).predicates {
if let ty::Predicate::Trait(ref poly_trait_predicate) = predicate {
let trait_ref = poly_trait_predicate.skip_binder().trait_ref;
let def_id = trait_ref.def_id;
if check_must_use_def(cx, def_id, span, "implementer of ", "") {
let descr_pre = &format!("{}implementer of ", descr_pre_path);
if check_must_use_def(cx, def_id, span, descr_pre, descr_post_path) {
has_emitted = true;
break;
}
@ -162,7 +171,8 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedResults {
for predicate in binder.skip_binder().iter() {
if let ty::ExistentialPredicate::Trait(ref trait_ref) = predicate {
let def_id = trait_ref.def_id;
if check_must_use_def(cx, def_id, span, "", " trait object") {
let descr_post = &format!(" trait object{}", descr_post_path);
if check_must_use_def(cx, def_id, span, descr_pre_path, descr_post) {
has_emitted = true;
break;
}
@ -181,7 +191,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedResults {
for (i, ty) in tys.iter().map(|k| k.expect_ty()).enumerate() {
let descr_post_path = &format!(" in tuple element {}", i);
let span = *spans.get(i).unwrap_or(&span);
if check_must_use_ty(cx, ty, expr, span, descr_post_path) {
if check_must_use_ty(cx, ty, expr, span, descr_pre_path, descr_post_path) {
has_emitted = true;
}
}

4
src/libstd/panicking.rs
View File

@ -103,7 +103,9 @@ pub fn set_hook(hook: Box<dyn Fn(&PanicInfo<'_>) + 'static + Sync + Send>) {
HOOK_LOCK.write_unlock();
if let Hook::Custom(ptr) = old_hook {
Box::from_raw(ptr);
#[allow(unused_must_use)] {
Box::from_raw(ptr);
}
}
}
}

4
src/test/run-pass/issues/issue-30530.rs
View File

@ -12,7 +12,9 @@ pub enum Handler {
}
fn main() {
take(Handler::Default, Box::new(main));
#[allow(unused_must_use)] {
take(Handler::Default, Box::new(main));
}
}
#[inline(never)]

2
src/test/run-pass/panics/panic-handler-flail-wildly.rs
View File

@ -1,5 +1,7 @@
// run-pass
#![allow(stable_features)]
#![allow(unused_must_use)]
// ignore-emscripten no threads support

17
src/test/ui/lint/must_use-trait.rs
View File

@ -17,6 +17,23 @@ fn get_critical() -> impl NotSoCritical + Critical + DecidedlyUnimportant {
Anon {}
}
fn get_boxed_critical() -> Box<dyn Critical> {
Box::new(Anon {})
}
fn get_nested_boxed_critical() -> Box<Box<dyn Critical>> {
Box::new(Box::new(Anon {}))
}
fn get_critical_tuple() -> (u32, Box<dyn Critical>, impl Critical, ()) {
(0, get_boxed_critical(), get_critical(), ())
}
fn main() {
get_critical(); //~ ERROR unused implementer of `Critical` that must be used
get_boxed_critical(); //~ ERROR unused boxed `Critical` trait object that must be used
get_nested_boxed_critical();
//~^ ERROR unused boxed boxed `Critical` trait object that must be used
get_critical_tuple(); //~ ERROR unused boxed `Critical` trait object in tuple element 1
//~^ ERROR unused implementer of `Critical` in tuple element 2
}

28
src/test/ui/lint/must_use-trait.stderr
View File

@ -1,5 +1,5 @@
error: unused implementer of `Critical` that must be used
--> $DIR/must_use-trait.rs:21:5
--> $DIR/must_use-trait.rs:33:5
|
LL | get_critical();
| ^^^^^^^^^^^^^^^
@ -10,5 +10,29 @@ note: lint level defined here
LL | #![deny(unused_must_use)]
| ^^^^^^^^^^^^^^^
error: aborting due to previous error
error: unused boxed `Critical` trait object that must be used
--> $DIR/must_use-trait.rs:34:5
|
LL | get_boxed_critical();
| ^^^^^^^^^^^^^^^^^^^^^
error: unused boxed boxed `Critical` trait object that must be used
--> $DIR/must_use-trait.rs:35:5
|
LL | get_nested_boxed_critical();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error: unused boxed `Critical` trait object in tuple element 1 that must be used
--> $DIR/must_use-trait.rs:37:5
|
LL | get_critical_tuple();
| ^^^^^^^^^^^^^^^^^^^^^
error: unused implementer of `Critical` in tuple element 2 that must be used
--> $DIR/must_use-trait.rs:37:5
|
LL | get_critical_tuple();
| ^^^^^^^^^^^^^^^^^^^^^
error: aborting due to 5 previous errors

2
src/tools/miri

@ -1 +1 @@
Subproject commit 945f007c0d305c3ec069b5e5d911ef783f6d70e7
Subproject commit 72b2e1045d642c517347c421b1db92e34c22a70d