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rewrite ensure_drop_params_and_item_params_correspond

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This commit is contained in:
lcnr 2022-03-23 10:06:29 +01:00
parent f3f68324cc
commit 5ac973426e
6 changed files with 71 additions and 126 deletions
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99
compiler/rustc_typeck/src/check/dropck.rs
View file

@ -2,17 +2,13 @@ use crate::check::regionck::RegionCtxt;
use crate::hir;
use crate::hir::def_id::{DefId, LocalDefId};
use rustc_errors::{struct_span_err, ErrorGuaranteed};
use rustc_infer::infer::outlives::env::OutlivesEnvironment;
use rustc_infer::infer::{InferOk, RegionckMode, TyCtxtInferExt};
use rustc_infer::traits::TraitEngineExt as _;
use rustc_middle::ty::error::TypeError;
use rustc_middle::ty::relate::{Relate, RelateResult, TypeRelation};
use rustc_middle::ty::subst::{Subst, SubstsRef};
use rustc_middle::ty::{self, EarlyBinder, Predicate, Ty, TyCtxt};
use rustc_middle::ty::subst::SubstsRef;
use rustc_middle::ty::{self, Predicate, Ty, TyCtxt};
use rustc_span::Span;
use rustc_trait_selection::traits::error_reporting::InferCtxtExt;
use rustc_trait_selection::traits::query::dropck_outlives::AtExt;
use rustc_trait_selection::traits::{ObligationCause, TraitEngine, TraitEngineExt};
use rustc_trait_selection::traits::ObligationCause;
/// This function confirms that the `Drop` implementation identified by
/// `drop_impl_did` is not any more specialized than the type it is
@ -39,8 +35,8 @@ pub fn check_drop_impl(tcx: TyCtxt<'_>, drop_impl_did: DefId) -> Result<(), Erro
ensure_drop_params_and_item_params_correspond(
tcx,
drop_impl_did.expect_local(),
dtor_self_type,
adt_def.did(),
self_to_impl_substs,
)?;
ensure_drop_predicates_are_implied_by_item_defn(
@ -67,75 +63,34 @@ pub fn check_drop_impl(tcx: TyCtxt<'_>, drop_impl_did: DefId) -> Result<(), Erro
fn ensure_drop_params_and_item_params_correspond<'tcx>(
tcx: TyCtxt<'tcx>,
drop_impl_did: LocalDefId,
drop_impl_ty: Ty<'tcx>,
self_type_did: DefId,
drop_impl_substs: SubstsRef<'tcx>,
) -> Result<(), ErrorGuaranteed> {
let drop_impl_hir_id = tcx.hir().local_def_id_to_hir_id(drop_impl_did);
let Err(arg) = tcx.uses_unique_generic_params(drop_impl_substs, false) else {
return Ok(())
};
// check that the impl type can be made to match the trait type.
tcx.infer_ctxt().enter(|ref infcx| {
let impl_param_env = tcx.param_env(self_type_did);
let tcx = infcx.tcx;
let mut fulfillment_cx = <dyn TraitEngine<'_>>::new(tcx);
let named_type = tcx.type_of(self_type_did);
let drop_impl_span = tcx.def_span(drop_impl_did);
let fresh_impl_substs =
infcx.fresh_substs_for_item(drop_impl_span, drop_impl_did.to_def_id());
let fresh_impl_self_ty = EarlyBinder(drop_impl_ty).subst(tcx, fresh_impl_substs);
let cause = &ObligationCause::misc(drop_impl_span, drop_impl_hir_id);
match infcx.at(cause, impl_param_env).eq(named_type, fresh_impl_self_ty) {
Ok(InferOk { obligations, .. }) => {
fulfillment_cx.register_predicate_obligations(infcx, obligations);
}
Err(_) => {
let item_span = tcx.def_span(self_type_did);
let self_descr = tcx.def_kind(self_type_did).descr(self_type_did);
let reported = struct_span_err!(
tcx.sess,
drop_impl_span,
E0366,
"`Drop` impls cannot be specialized"
)
.span_note(
item_span,
&format!(
"use the same sequence of generic type, lifetime and const parameters \
as the {self_descr} definition",
),
)
.emit();
return Err(reported);
}
let drop_impl_span = tcx.def_span(drop_impl_did);
let item_span = tcx.def_span(self_type_did);
let self_descr = tcx.def_kind(self_type_did).descr(self_type_did);
let mut err =
struct_span_err!(tcx.sess, drop_impl_span, E0366, "`Drop` impls cannot be specialized");
match arg {
ty::util::NotUniqueParam::DuplicateParam(arg) => {
err.note(&format!("`{arg}` is mentioned multiple times"))
}
let errors = fulfillment_cx.select_all_or_error(&infcx);
if !errors.is_empty() {
// this could be reached when we get lazy normalization
let reported = infcx.report_fulfillment_errors(&errors, None, false);
return Err(reported);
ty::util::NotUniqueParam::NotParam(arg) => {
err.note(&format!("`{arg}` is not a generic parameter"))
}
// NB. It seems a bit... suspicious to use an empty param-env
// here. The correct thing, I imagine, would be
// `OutlivesEnvironment::new(impl_param_env)`, which would
// allow region solving to take any `a: 'b` relations on the
// impl into account. But I could not create a test case where
// it did the wrong thing, so I chose to preserve existing
// behavior, since it ought to be simply more
// conservative. -nmatsakis
let outlives_env = OutlivesEnvironment::new(ty::ParamEnv::empty());
infcx.resolve_regions_and_report_errors(
drop_impl_did.to_def_id(),
&outlives_env,
RegionckMode::default(),
);
Ok(())
})
};
err.span_note(
item_span,
&format!(
"use the same sequence of generic type, lifetime and const parameters \
as the {self_descr} definition",
),
);
Err(err.emit())
}
/// Confirms that every predicate imposed by dtor_predicates is

18
compiler/rustc_typeck/src/coherence/orphan.rs
View file

@ -383,20 +383,13 @@ fn lint_auto_trait_impls(tcx: TyCtxt<'_>, trait_def_id: DefId, impls: &[LocalDef
tcx.hir().local_def_id_to_hir_id(impl_def_id),
tcx.def_span(impl_def_id),
|err| {
let item_span = tcx.def_span(self_type_did);
let self_descr = tcx.def_kind(self_type_did).descr(self_type_did);
let mut err = err.build(&format!(
"cross-crate traits with a default impl, like `{}`, \
should not be specialized",
tcx.def_path_str(trait_def_id),
));
let item_span = tcx.def_span(self_type_did);
let self_descr = tcx.def_kind(self_type_did).descr(self_type_did);
err.span_note(
item_span,
&format!(
"try using the same sequence of generic parameters as the {} definition",
self_descr,
),
);
match arg {
ty::util::NotUniqueParam::DuplicateParam(arg) => {
err.note(&format!("`{}` is mentioned multiple times", arg));
@ -405,6 +398,13 @@ fn lint_auto_trait_impls(tcx: TyCtxt<'_>, trait_def_id: DefId, impls: &[LocalDef
err.note(&format!("`{}` is not a generic parameter", arg));
}
}
err.span_note(
item_span,
&format!(
"try using the same sequence of generic parameters as the {} definition",
self_descr,
),
);
err.emit();
},
);

10
src/test/ui/auto-traits/suspicious-impls-lint.stderr
View file

@ -11,12 +11,12 @@ LL | #![deny(suspicious_auto_trait_impls)]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^
= warning: this will change its meaning in a future release!
= note: for more information, see issue #93367 <https://github.com/rust-lang/rust/issues/93367>
= note: `&T` is not a generic parameter
note: try using the same sequence of generic parameters as the struct definition
--> $DIR/suspicious-impls-lint.rs:8:1
|
LL | struct MayImplementSendErr<T>(T);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
= note: `&T` is not a generic parameter
error: cross-crate traits with a default impl, like `Send`, should not be specialized
--> $DIR/suspicious-impls-lint.rs:21:1
@ -26,12 +26,12 @@ LL | unsafe impl Send for ContainsVec<i32> {}
|
= warning: this will change its meaning in a future release!
= note: for more information, see issue #93367 <https://github.com/rust-lang/rust/issues/93367>
= note: `i32` is not a generic parameter
note: try using the same sequence of generic parameters as the struct definition
--> $DIR/suspicious-impls-lint.rs:20:1
|
LL | struct ContainsVec<T>(Vec<T>);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
= note: `i32` is not a generic parameter
error: cross-crate traits with a default impl, like `Send`, should not be specialized
--> $DIR/suspicious-impls-lint.rs:32:1
@ -41,12 +41,12 @@ LL | unsafe impl<T: Send> Send for TwoParamsSame<T, T> {}
|
= warning: this will change its meaning in a future release!
= note: for more information, see issue #93367 <https://github.com/rust-lang/rust/issues/93367>
= note: `T` is mentioned multiple times
note: try using the same sequence of generic parameters as the struct definition
--> $DIR/suspicious-impls-lint.rs:31:1
|
LL | struct TwoParamsSame<T, U>(T, U);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
= note: `T` is mentioned multiple times
error: cross-crate traits with a default impl, like `Send`, should not be specialized
--> $DIR/suspicious-impls-lint.rs:40:1
@ -56,12 +56,12 @@ LL | unsafe impl<T> Send for WithPhantomDataSend<*const T, i8> {}
|
= warning: this will change its meaning in a future release!
= note: for more information, see issue #93367 <https://github.com/rust-lang/rust/issues/93367>
= note: `*const T` is not a generic parameter
note: try using the same sequence of generic parameters as the struct definition
--> $DIR/suspicious-impls-lint.rs:39:1
|
LL | pub struct WithPhantomDataSend<T, U>(PhantomData<T>, U);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
= note: `*const T` is not a generic parameter
error: cross-crate traits with a default impl, like `Sync`, should not be specialized
--> $DIR/suspicious-impls-lint.rs:46:1
@ -71,12 +71,12 @@ LL | unsafe impl<T> Sync for WithLifetime<'static, Vec<T>> {}
|
= warning: this will change its meaning in a future release!
= note: for more information, see issue #93367 <https://github.com/rust-lang/rust/issues/93367>
= note: `Vec<T>` is not a generic parameter
note: try using the same sequence of generic parameters as the struct definition
--> $DIR/suspicious-impls-lint.rs:44:1
|
LL | pub struct WithLifetime<'a, T>(&'a (), T);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
= note: `Vec<T>` is not a generic parameter
error: aborting due to 5 previous errors

1
src/test/ui/dropck/issue-38868.stderr
View file

@ -8,6 +8,7 @@ LL | | }
LL | | }
| |_^
|
= note: `i32` is not a generic parameter
note: use the same sequence of generic type, lifetime and const parameters as the struct definition
--> $DIR/issue-38868.rs:1:1
|

6
src/test/ui/dropck/reject-specialized-drops-8142.rs
View file

@ -32,9 +32,7 @@ impl<'al,'adds_bnd> Drop for L<'al,'adds_bnd> where 'adds_bnd:'al { // RE
impl<'ml> Drop for M<'ml> { fn drop(&mut self) { } } // ACCEPT
impl Drop for N<'static> { fn drop(&mut self) { } } // REJECT
//~^ ERROR mismatched types
//~| expected struct `N<'n>`
//~| found struct `N<'static>`
//~^ ERROR `Drop` impls cannot be specialized
impl<COkNoBound> Drop for O<COkNoBound> { fn drop(&mut self) { } } // ACCEPT
@ -57,7 +55,7 @@ impl<One> Drop for V<One,One> { fn drop(&mut self) { } } // REJECT
//~^ ERROR `Drop` impls cannot be specialized
impl<'lw> Drop for W<'lw,'lw> { fn drop(&mut self) { } } // REJECT
//~^ ERROR cannot infer an appropriate lifetime for lifetime parameter `'lw`
//~^ ERROR `Drop` impls cannot be specialized
impl Drop for X<3> { fn drop(&mut self) { } } // REJECT
//~^ ERROR `Drop` impls cannot be specialized

63
src/test/ui/dropck/reject-specialized-drops-8142.stderr
View file

@ -22,27 +22,26 @@ note: the implementor must specify the same requirement
LL | struct L<'l1,'l2> { x: &'l1 i8, y: &'l2 u8 }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error[E0308]: mismatched types
error[E0366]: `Drop` impls cannot be specialized
--> $DIR/reject-specialized-drops-8142.rs:34:1
|
LL | impl Drop for N<'static> { fn drop(&mut self) { } } // REJECT
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ lifetime mismatch
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: expected struct `N<'n>`
found struct `N<'static>`
note: the lifetime `'n` as defined here...
--> $DIR/reject-specialized-drops-8142.rs:7:10
= note: `'static` is not a generic parameter
note: use the same sequence of generic type, lifetime and const parameters as the struct definition
--> $DIR/reject-specialized-drops-8142.rs:7:1
|
LL | struct N<'n> { x: &'n i8 }
| ^^
= note: ...does not necessarily outlive the static lifetime
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
error[E0366]: `Drop` impls cannot be specialized
--> $DIR/reject-specialized-drops-8142.rs:41:1
--> $DIR/reject-specialized-drops-8142.rs:39:1
|
LL | impl Drop for P<i8> { fn drop(&mut self) { } } // REJECT
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: `i8` is not a generic parameter
note: use the same sequence of generic type, lifetime and const parameters as the struct definition
--> $DIR/reject-specialized-drops-8142.rs:9:1
|
@ -50,7 +49,7 @@ LL | struct P<Tp> { x: *const Tp }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error[E0367]: `Drop` impl requires `AddsBnd: Bound` but the struct it is implemented for does not
--> $DIR/reject-specialized-drops-8142.rs:44:14
--> $DIR/reject-specialized-drops-8142.rs:42:14
|
LL | impl<AddsBnd:Bound> Drop for Q<AddsBnd> { fn drop(&mut self) { } } // REJECT
| ^^^^^
@ -62,7 +61,7 @@ LL | struct Q<Tq> { x: *const Tq }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error[E0367]: `Drop` impl requires `AddsRBnd: 'rbnd` but the struct it is implemented for does not
--> $DIR/reject-specialized-drops-8142.rs:47:21
--> $DIR/reject-specialized-drops-8142.rs:45:21
|
LL | impl<'rbnd,AddsRBnd:'rbnd> Drop for R<AddsRBnd> { fn drop(&mut self) { } } // REJECT
| ^^^^^
@ -74,47 +73,38 @@ LL | struct R<Tr> { x: *const Tr }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error[E0366]: `Drop` impls cannot be specialized
--> $DIR/reject-specialized-drops-8142.rs:56:1
--> $DIR/reject-specialized-drops-8142.rs:54:1
|
LL | impl<One> Drop for V<One,One> { fn drop(&mut self) { } } // REJECT
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: `One` is mentioned multiple times
note: use the same sequence of generic type, lifetime and const parameters as the struct definition
--> $DIR/reject-specialized-drops-8142.rs:15:1
|
LL | struct V<Tva, Tvb> { x: *const Tva, y: *const Tvb }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error[E0495]: cannot infer an appropriate lifetime for lifetime parameter `'lw` due to conflicting requirements
--> $DIR/reject-specialized-drops-8142.rs:59:1
error[E0366]: `Drop` impls cannot be specialized
--> $DIR/reject-specialized-drops-8142.rs:57:1
|
LL | impl<'lw> Drop for W<'lw,'lw> { fn drop(&mut self) { } } // REJECT
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
note: first, the lifetime cannot outlive the lifetime `'l1` as defined here...
--> $DIR/reject-specialized-drops-8142.rs:16:10
= note: `'lw` is mentioned multiple times
note: use the same sequence of generic type, lifetime and const parameters as the struct definition
--> $DIR/reject-specialized-drops-8142.rs:16:1
|
LL | struct W<'l1, 'l2> { x: &'l1 i8, y: &'l2 u8 }
| ^^^
note: ...but the lifetime must also be valid for the lifetime `'l2` as defined here...
--> $DIR/reject-specialized-drops-8142.rs:16:15
|
LL | struct W<'l1, 'l2> { x: &'l1 i8, y: &'l2 u8 }
| ^^^
note: ...so that the types are compatible
--> $DIR/reject-specialized-drops-8142.rs:59:1
|
LL | impl<'lw> Drop for W<'lw,'lw> { fn drop(&mut self) { } } // REJECT
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
= note: expected `W<'l1, 'l2>`
found `W<'_, '_>`
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error[E0366]: `Drop` impls cannot be specialized
--> $DIR/reject-specialized-drops-8142.rs:62:1
--> $DIR/reject-specialized-drops-8142.rs:60:1
|
LL | impl Drop for X<3> { fn drop(&mut self) { } } // REJECT
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: `3_usize` is not a generic parameter
note: use the same sequence of generic type, lifetime and const parameters as the struct definition
--> $DIR/reject-specialized-drops-8142.rs:17:1
|
@ -122,11 +112,12 @@ LL | struct X<const Ca: usize>;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
error[E0366]: `Drop` impls cannot be specialized
--> $DIR/reject-specialized-drops-8142.rs:65:1
--> $DIR/reject-specialized-drops-8142.rs:63:1
|
LL | impl<const Ca: usize> Drop for Y<Ca, Ca> { fn drop(&mut self) { } } // REJECT
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: `Ca` is mentioned multiple times
note: use the same sequence of generic type, lifetime and const parameters as the struct definition
--> $DIR/reject-specialized-drops-8142.rs:18:1
|
@ -134,7 +125,7 @@ LL | struct Y<const Ca: usize, const Cb: usize>;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error[E0367]: `Drop` impl requires `AddsBnd: Bound` but the enum it is implemented for does not
--> $DIR/reject-specialized-drops-8142.rs:68:14
--> $DIR/reject-specialized-drops-8142.rs:66:14
|
LL | impl<AddsBnd:Bound> Drop for Enum<AddsBnd> { fn drop(&mut self) { } } // REJECT
| ^^^^^
@ -146,7 +137,7 @@ LL | enum Enum<T> { Variant(T) }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^
error[E0367]: `Drop` impl requires `AddsBnd: Bound` but the struct it is implemented for does not
--> $DIR/reject-specialized-drops-8142.rs:71:14
--> $DIR/reject-specialized-drops-8142.rs:69:14
|
LL | impl<AddsBnd:Bound> Drop for TupleStruct<AddsBnd> { fn drop(&mut self) { } } // REJECT
| ^^^^^
@ -158,7 +149,7 @@ LL | struct TupleStruct<T>(T);
| ^^^^^^^^^^^^^^^^^^^^^^^^^
error[E0367]: `Drop` impl requires `AddsBnd: Bound` but the union it is implemented for does not
--> $DIR/reject-specialized-drops-8142.rs:74:21
--> $DIR/reject-specialized-drops-8142.rs:72:21
|
LL | impl<AddsBnd:Copy + Bound> Drop for Union<AddsBnd> { fn drop(&mut self) { } } // REJECT
| ^^^^^
@ -171,5 +162,5 @@ LL | union Union<T: Copy> { f: T }
error: aborting due to 13 previous errors
Some errors have detailed explanations: E0308, E0366, E0367, E0495.
For more information about an error, try `rustc --explain E0308`.
Some errors have detailed explanations: E0366, E0367.
For more information about an error, try `rustc --explain E0366`.